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UNIVERSITY OF CALIFORNIA SCRIPPS INSTITUTION OF OCEANOGRAPHY
CONTRIBUTIONS 1960
This volume contains contributions from the Scripps Institution of Oceanography which appeared during 1960 in publications other than Bulletins of the Scripps Institution of Oceanography.
THE LIBRARY UNIVERSITY OF CALIFORNIA SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA, CALIFORNIA
June 1961
PHOTOLITHOPRINTED BY CUSHING - MALLOY, INC. ANN ARBOR, MICHIGAN, UNITED STATES OF AMERICA 1961
Contrib, Number
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
UNIVERSITY OF CALIFORNIA SCRIPPS INSTITUTION OF OCEANOGRAPHY CONTRIBUTIONS, NEW SERIES
vn 1960
NUMERICAL INDEX
INMAN, DOUGLAS L. and JEAN H. FILLOUX. Beach cycles related to tide and local wind wave regime. Journal of Geology,
Wa) 0G, DOsce Mah 1960, DD Se Dao des: ois5 th: bhiis peel venus ye om, 6 900 reels
NORDSTROM, SVANTE G. and THEODORE R. FOLSOM. Suggestion for eliminating pressure effects on protected re-
versing thermometers. Deep-Sea Research, v. 6, 1960. p. 169...
McGOWAN, JOHN A. The relationship of the distribution of the planktonic worm, Poeobius meseres Heath, to the water masses of the North Pacific. Deep-Sea Research, v. 6, 1960.
IPOD ee Se seve a rdibne. bane 6 are SRD Re Sects UAE te: Cees
DAWSON, E. YALE, MICHAEL NEUSHUL and ROBERT D. WILDMAN. Seaweeds associated with kelp beds along southern California and northwestern Mexico. Pacific Naturalist, v. 1,
Bae, nT Cn ts L9G0s DOK LKB Lo ii ict ce Hs pe eich e ee db ceceneye
LAL, DEVENDRA, EDWARD D. GOLDBERG and MINORU KOIDE. Cosmic-ray-produced silicon-32 in nature. Science,
v. 131, no. 3397, February 5, 1960. pp. 332-337. ............
RODEN, GUNNAR I. and GORDON W. GROVES. On the statistical prediction of ocean temperatures. Journal of Geo-
physical Research, v. 65, no. 1, January 1960. pp. 249-263 .....
LAL, DEVENDRA and DAVID R. SCHINK. Low background thin-wall flow counters for measuring beta activity of solids. Review of Scientific Instruments, v. 31, no. 4, April 1960.
Oe OS ee ee Se ee mee ee gee a ee ee
ROBINSON, MARGARET K. Indian Ocean vertical temper-
ature sections. Deep-Sea Research, v. 6, 1960. pp. 249-258.....
TALLING, JACK F. Comparative laboratory and field studies of photosynthesis by a marine planktonic diatom. Limnology
and Oceanography, v. 5, no. 1, January 1960. pp. 62-77........
LASKER, REUBEN. Utilization of organic carbon by a ma- rine crustacean: analysis with carbon-14. Science, v. 131,
nowes01, mpril 15, 1960. pp: 1098-1100 .. ee ee ee
FISHER, ROBERT L. and ROBERT M. NORRIS. Bathymetry and geology of Sala y Gomez, Southeast Pacific. Geological
Society of America, Bulletin, v. 71, April 1960. pp. 497-502.....
v
11
13
29
Contrib.
Number
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
UCHIO, TAKAYASU.: Ecology of living benthonic Foraminifera from the San Diego, California, area. Cushman Foundation for Foraminiferal Research, Special pokleation: No. 5, April 20,
1960. pps Lata areesce tenets cette, Gite errs tebierve: os ONS th fell oteblowlst eens (nemo iettoige
TYLER, JOHN E. Radiance distribution as a function of depth in an underwater environment.. Scripps Institution of Ocean- ography of the University of California, La Jolla, California,
Bulletin, v. 7, no. 5, March 18, 1960. pp. 363-412 ...........
SCHOLANDER, PER F. Oxygen transport through hemoglobin solutions. Science, v. 131, no. 3400, February 26, 1960.
PD. 885-590) wrists SOC Ree ie ee ies) «atte de Ped uel tye) aoe ete
VAN DORN, WILLIAM G. A new long-period wave recorder. Journal of Geophysical Research, v. 65, no. 3, March 1960.
pp. 1007s1Ol2a3 e.g CRA Shes Co ARE eee
GOLDBERG, EDWARD D. and ROBERT H. PARKER. Phosphatized wood from the Pacific sea floor. Geological
Society of America, Bulletin, v. 71, May 1960. pp. 631-632 .....
EWING, GIFFORD C. and EDWARD D. McALISTER. On the thermal boundary layer of the ocean. Science, v. 131, no. 3410,
May’ 6, 1960." pp. TST4-13TG thoes: ota aie) stature bere cane owes
WOOSTER, WARREN S. and GORDON H. VOLKMANN. In- dications of deep Pacific circulation from the distribution of properties at five kilometers, Journal of Geophysical Re-
search, v. 65, no. 4, April 1960. pp. 1239-1249 .............
JOHNSON, MARTIN W. Production and distribution of larvae of the spiny lobster, Panulirus interruptus (Randall) with rec- ords on P. gracilis Streets. Scripps Institution of Oceanog- raphy of the University of California, La Jolla, California, Bulletin, v. 7, no. 6, May 23, 1960. pp. 413-462
HUBBS, CARL L., GEORGE S. BIEN and HANS E. SUESS. La Jolla natural radiocarbon measurements. American Jour- nal of Science Radiocarbon Supplement, v. 2, 1960. pp. 197-
223 1. 6 Sets Li Sealy Biscae wid oa? a Aenean oak Retctagneuie tae) Mame
VAN ANDEL, TJEERD H. and DAVID M. POOLE. Sources of recent sediments in the northern Gulf of Mexico. Journal of Sedimentary Petrology, v. 30, no. 1, March 1960. pp. 91-
122
MILLER, ROBERT RUSH and CARL L. HUBBS. The spiny- rayed cyprinid fishes (Plagopterini) of the Colorado River system. Museum of Zoology, University of Michigan, Mis- cellaneous Publications, No. 115, July 5, 1960. pp. 1-39
ARTHUR, ROBERT S. A review of the calculation of ocean currents at the equator, Deep-Sea Research, v. 6, 1960. pp. 287-297
* Not available for exchange,
vi
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9 © © 9, 6° e 6 e's 6 8 6 6) OU be le eRe) em 68 eee elie eh SUG Cel al wisn iain) fe
Page Number
177
259
265
271
273
275
287
Contrib. Number
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
KNAUSS, JOHN A. Measurements of the Cromwell Current. Deep-Sea Research, v. 6, 1960. pp. 265-286
ROSENBLATT, RICHARD H. The Atlantic species of the blennioid fish genus Enneanectes. Academy of Natural Sci- ences of Philadélphia, Proceedings, v. 112, no. 1, June 17, 1960. pp. 1-23
BODEN, BRIAN P., ELIZABETH M. KAMPA and JAMES M. SNODGRASS. Underwater daylight measurements in the Bay of Biscay. Marine Biological Association of the United Kingdom, Journal, v. 39, 1960. pp. 227-238
LANKFORD, ROBERT R. and FRANCIS P. SHEPARD. Facies interpretations in Mississippi Delta borings. Journal
of Geology, v. 68, no. 4, July 1960. pp. 408-426.............
PHLEGER, FRED B. Ecology and distribution of recent Foraminifera, The Johns Hopkins Press, Baltimore, pp. viii, 1-297
RUDNICK, PHILIP. Small signal detection in the DIMUS array. Acoustical Society of America, Journal, v. 32, no. 7,
MARS oD: LO 08 Vili 22 tore <5 ils ue ite. swan eee enon Gino Geiss Suske
ANDERSON, VICTOR C. Digital array phasing. Acoustical Society of America, Journal, v. 32, no. 7, July 1960. pp. 867-
RS oe eee a i re ot ee ee pe
BALECH, ENRIQUE. The changes in the phytoplankton popu- lation off the California coast. California Cooperative Oceanic Fisheries Investigations, Reports v. 7, January 1, 1958-June
Dery Meee VR MeL aoe is ph he te orale Hue UG RTA ele ehalts alas: a
BERNER, LEO D. Unusual features in the distribution of pelagic tunicates in 1957 and 1958. California Cooperative Oceanic Fisheries Investigations, Reports v. 7, January 1,
19pe—sune 90; 1999. pps 193-1395 eee ii eke abl s pie 5 She Ne 0 oh e ue
BRINTON, EDWARD. Changes in the distribution of euphau- siid crustaceans in the region of the California Current. California Cooperative Oceanic Fisheries Investigations,
Reports v. 7, January 1, 1958-June 30, 1959. pp. 137-146......
HUBBS, CARL L. Quaternary paleoclimatology of the Pacific coast of North America. California Cooperative Oceanic Fisheries Investigations, Reports v. 7, January 1, 1958-June
ol aN C2 ip be as ee rr
JOHNSON, MARTIN W. The offshore drift of larvae of the California spiny lobster Panulirus interruptus. California Cooperative Oceanic Fisheries Investigations, Reports v. 7,
January 1, 1006-June 30, 1959. pp. 147-161"... ... 1... ee ee
* Not available for exchange.
vii
O fe) 6. CVS) Saf 10) lye Sie 6, oT D>
oe 6 2S RO eS Oe OB NT OR! SO Ry et SSS) Buel ie We erey wa
Ore. Che (ote oC bert wp, ae weer ecs ie \s
ae e218 & eeeye bo OS 6 we) ee) es 0 ¥ we ele Beier ae 8 tt io e' 2 8
Page Number
403
425
451
465
487
‘495
499
505
509
519
527
Contrib. Number
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
REID, JOSEPH L., JR. Oceanography of the northeastern Pa-
cific Ocean during the last ten years. California Cooperative Oceanic Fisheries Investigations, Reports v. 7, January 1, 1958- June SOVL959 pp cal 90 etic Oo cacans sheer yaqrans N. saudenauee he PE Sapeeer eae hae
WOOSTER, WARREN S&S. El Nivio. California Cooperative Oceanic Fisheries Investigations, Reports v. 7, January 1, 1958- June’ 305-1959.- pp. 43-45:..00. cs 6 RY. Oy. Sis: UR eterna ucr.
ROBINSON, MARGARET K. Statistical evidence indicating no long-term climatic change in the deep waters of the North and South Pacific Oceans. Journal of Geophysical Research, v. 65, no,'7, July 1960.q pps 209 Ts2U 16s g see, cs Pe > ele el
RASMUSSEN, ROBERT A. Low frequency wave filters em- ploying thermistors. Review of Scientific Instruments, v. 31, no. :7, July/1960, pple 15 lhc rg ature om s FE ees Shete emetaeee «
ECKART, CARL. Variation principles of hydrodynamics. Physics of Fluids, v. 3, no. 3, May-June 1960. pp. 421-427.......
ECKART, CARL H. Hydrodynamics of oceans and atmos- pheres. Pergamon Press, New York, pp. xi, 1-290 ............
PHLEGER, FRED B. Foraminiferal populations in Laguna ~
Madre, Texas. Science Reports, Tohoku University, Sendai,
Japan, Second Series (Geology), Special Volume, No. 4
(Hanzawa Memorial Volume), March 1960. pp. 83-91...........
PARKER, FRANCES L. Living planktonic Foraminifera from
the equatorial and southeast Pacific. Science Reports, Tohoku University, Sendai, Japan, Second Series (Geology), Special
Volume, No. 4 (Hanzawa Memorial Volume), March 1960.
PP. 11-826. ohn: io) slop Gig a Seapets Hae Decal ig Peete? RTs Se CRU ren y
MASON, RONALD G. Geophysical investigations of the sea floor. Liverpool and Manchester Geological Journal, v. 2, part'3,7 1960 pp.*389-41 0 Re aes, 2 ene ee nc etine ooeeatrte nna
ZOBELL, CLAUDE E. Marine poilution problems in the
southern California area. Transactions of the Second Seminar
on Biological Problems in Water Pollution, April 20-24, 1959.
DPS UTT= 18S Se a ie eee ere ee ee ee
SHUMWAY, GEORGE A. Sound speed and absorption studies
of marine sediments by a resonance method--Parts I and II. Geophysics, v, 25, nos. 2 and 3, April and June, 1960. Part I,
pp. 45f-4675 Part Il, pp, G50<OS2 40". ences ee eee ee ee ee
MENARD, HENRY W. Possible pre-Pleistocene deep-sea fans off central California. Geological Society of America, Bulletin, v. 71, August 1960) pp. t27letatG 0. 7 ee
O’hEOCHA, COLM and FRANCIS T. HAXO. Some atypical algal chromoproteins, Biochimica et Biophysica Acta, v. 41, 1960. pp. 516-520
Oe Me He Bye B66 (0 ney Te Le Ve eye ere eet Ven lenle awe lle” Gig el ele
* Not available for exchange.
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Page Number
Contrib, Number
1187
1188 1189 1190
1191
1192 1193
1194
1195
1196
1197
1198
1199
1200
1201
LEIGHTON, DAVID L. An abalone lacking respiratory aper-
tures. The Veliger, v. 3, no. 2, October 1960. p. 48..........
KEELING, CHARLES D. The concentration and isotopic abun- dances of carbon dioxide in the atmosphere. Tellus, v. 12, no, 2, June 1960. pp. 200-203
SCHAEFER, MILNER B. New research required in support of radioactive waste disposal. Proceedings of the Scientific Conference on the Disposal of Radio-active Wastes, Monaco, November 16-21, 1959. pp. 265-282
MENARD, HENRY W. Consolidated slabs on the floor of the
Eastern Pacific. Deep-Sea Research, v. 7, 1960. pp. 35-41.....
KNAUSS, JOHN A. Observations of irregular motion in the
open ocean. Deep-Sea Research, v. 7, 1960. pp. 68-69........
FILLOUX, JEAN H. and GORDON W. GROVES. A seasonal mean sea-level indicator. Deep-Sea Research, v. 7, 1960.
POMPE ER Ayiponl > «ise niibs ail o1e558 SOE We SOR. KEE.
JENNINGS, FEENAN D. and RICHARD A. SCHWARTZLOSE. Measurements of the California Current in March 1958. Deep-
pee Hegearch, v..15:1960.; Dp.42—4'pieeni since wiatatic vee acdeeers «
ISAACS, JOHN D. and GEORGE B. SCHICK. Deep-sea free
instrument vehicle. Deep-Sea Research, v. 7, 1960. pp. 61-67...
JANNASCH, HOLGER W. and GALEN E. JONES. Caulobacter sp. in sea water. Limnology and Oceanography, v. 5, no. 4,
Deiban sve “pp esoaaes 2; Polen? ieee ree os,
BARTHOLOMEW, GEORGE A. and CARL L. HUBBS. Popu- lation growth and seasonal movements of the northern elephant seal, Mireunga angustirostris. Mammalia, v. 24, no. 3, Septem-
ELIOT ID ONO ae cee. ies eins Bc cote wate thee ec eee 8
CRAIG, HARMON. The thermodynamics of sea water. National Academy of Sciences, Proceedings, v. 46, no, 9, September 1960.
Pe RN eMC IEE gates) ios ce Mgtlemhive Iwicw ssh ee ve eos louse, wi 'el a seive
ISAACS, JOHN D. and JOHN E. TYLER. On the observation of unresolved surface features of a planet. Astronomical So- ciety of the Pacific, Publications, v. 72, no. 426, June 1960.
EE relies a hak, wa mo e006 6. Gp oe’ b eQiiensl eee» visible ty G27
SHOR, GEORGE G., JR. Crustal structure of the Hawaiian Ridge near Gardner Pinnacles. Seismological Society of Amer-
ica, Bulletin, v. 50, no. 4, October 1960. pp. 563-573 .........
HAXO, FRANCIS T. The wavelength dependence of photosyn- thesis and the role of accessory pigments. In “Comparative Biochemistry of Photoreactive Systems,” edited by Mary Belle
Allen, New York, Academic Press 1960. pp. 339-360 .........
FOX, DENIS L. Pigments of plant origin in animal phyla. In “Comparative Biochemistry of Photoreactive Systems,” edited
by Mary Belle Allen, New York, Academic Press 1960. pp. 11-31.
ix
aw whew e.e he, 9 6. aye ere Be) Wee @ Bye aw ela,
oe RP whe Cw ere Bea er erie «6 6. se e
Page
Number
713
717
725
745
755
757
769
775
783
785
799
805
815
827
851
Contrib. Number
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
SHEPARD, FRANCIS P. Sediment environments of the north- west Gulf of Mexico. Eclogae geologicae Helvetiae, v. 51, no. 3,
December:1959= pp 598-6O8i fens soho celts, era fetld se uedebemedede «ls
FOLSOM, THEODORE R., GOVINDARAJU J. MOHANRAO and PERRIN WINCHELL. Fall-out caesium in surface sea water off the California coast (1959-60) by gamma-ray measurements.
Nature, v. 187, no. 4736, August 6, 1960. pp. 480-482 ...... Reeve
RODEN, GUNNAR I. On the nonseasonal variations in sea level along the west coast of North America. Journal of Geophysical
Research, v. 65, no. 9, September 1960. pp. 2809-2826 .........
GOLDBERG, EDWARD D. Chemists and the oceans. Chymia,
V5. 65:4960.+ pps246261.19 055 co ele anaes ies! eh Rs ST ee
VAN DORN, WILLIAM G. A low-frequency microbarograph. Journal of Geophysical Research, v. 65, no. 11, November 1960.
PDs 3693 - SO 9G 9 oS telicew dutacse rae ue Wie Pra Se coho hepa ee a eas Dench BememTS. <.c
MENARD, HENRY W. The East Pacific Rise. Science, v. 132,
no. 3441, December 9, 1960. pp. 1737-1746 ........0.2..000...
SHEPARD, FRANCIS P. Mississippi Delta: marginal environ- ments, sediments, and growth. In “Recent Sediments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American Association of
Petroleum. Geologists, 1960. ~ppo..56-Sier. sc Pe tea ew erates
SHEPARD, FRANCIS P. Rise of sea level along northwest Gulf of Mexico. In “Recent Sediments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American Association of Petroleum Geologists,
ee ad 9) aC Sa 5 ane Rarer eau et Car uO aCe ment racaciie keecwo TE eT C
SHEPARD, FRANCIS P. Gulf Coast barriers. In “Recent Sedi- ments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American Association of Petroleum Geologists, 1960. pp. 197-220
SHEPARD, FRANCIS P. and DAVID G. MOORE, Bays of central Texas coast. In “Recent Sediments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American Association of Petroleum
Geologists, 1960;*pps TLi-152e oe ee eee ee ee.
VAN ANDEL, TJEERD H. Sources and dispersion of Holocene sediments, northern Gulf of Mexico. In “Recent Sediments, north- west Gulf of Mexico, 1951-1958,” edited by F. P, Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American Association of Petroleum Geologists, 1960. pp. 34-55
* Not available for exchange.
oe ee ee © we
or 81S Ce G16) 0 6 6s Lew ere epee « 6
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873
885
891
910
929
935
Contrib, Number
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
VAN ANDEL, TJEERD H. and JOSEPH R. CURRAY. Regional aspects of modern sedimentation in northern Gulf of Mexico and similar basins, and paleographic significance. In “Recent Sedi- ments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American
Association of Petroleum Geologists, 1960. pp. 345-364.......
CURRAY, JOSEPH R. Sediments and history of Holocene transgression, continental shelf, northwest Gulf of Mexico. In “Recent Sediments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American Association of Petroleum Geologists, 1960.
EE ART Od eR ede ee Os POPPIN ADs POS. i Pees
THOMAS, WILLIAM H. and ERNEST G. SIMMONS. Phyto- plankton production in the Mississippi Delta. In “Recent Sedi- ments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B, Phleger, and T. H. van Andel, Tulsa, American
Association of Petroleum Geologists, 1960. pp. 103-116........
PHLEGER, FRED B. Recent sedimentology, northwest Gulf of Mexico; retrospect and prospect. In “Recent Sediments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American Associa-
tion of Petroleum Geologists, 1960. pp. 365-367.............
PHLEGER, FRED B. Sedimentary patterns of microfaunas in northern Gulf of Mexico. In “Recent Sediments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American Association of
Petroleum Geologists, 1960. pp. 267-301 ee a cae were
PARKER, ROBERT H. Ecology and distributional patterns of marine macro-invertebrates, northern Gulf of Mexico. In “Re- cent Sediments, northwest Gulf of Mexico, 1951-1958,” edited by F. P. Shepard, F. B. Phleger, and T. H. van Andel, Tulsa, American Association of Petroleum Geologists, 1960. pp. 302-
Ee ee ee BP il te peer eter an, ale ict dare eke ea
BOWMAN, THOMAS E. The pelagic amphipod genus Para- themisto (Hyperiidea : Hyperiidae) in the North Pacific and ad- jacent Arctic Ocean. United States National Museum, Proceed-
ieee D112, 1034205 1060, “pp, 343-992... oo.
REID, JOSEPH L., JR. Pacific Ocean. In “McGraw-Hill
Encyclopedia of Science and Technology,” 1960. pp. 483-488.....
HUBBS, CARL L. and ROBERT RUSH MILLER. Potamarius, a new genus of Ariid catfishes from the fresh waters of Middle
America. Copeia, no. 2, June 29, 1960. pp. 101-112 ..........
WISEMAN, JOHN D. H. and WILLIAM R. RIEDEL. Tertiary sediments from the floor of the Indian Ocean. Deep-Sea Re-
Search, v. 7, no. 3, December 1960. pp. 215-217. ............
* Not available for exchange,
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Page Number
Contrib,
Number
1223
1224
1225
1226
1227
RICHARDS, ADRIAN F. Rates of marine erosion of tephra and lava at Isla San Benedicto, Mexico. International Geological Congress, XXI Session, Norden, 1960, Report, Part X, Subma-
rine Geology. pp. 59- 64 NOEL GEE IEE ESRF OREES age ashi, spelen Pore rye
FAIRBRIDGE, RHODES W. and HARRIS B. STEWART, JR. Alexa Bank, a drowned atoll on the Melanesian Border Plateau,
Deep-Sea Research, v. 7, no. 2, October 1960. pp. 100-116 .....
SHOR, GEORGE G., JR. and RUSSELL W. RAITT. Seismic studies in the southern California Continental Borderland, Congreso Geologico Internacional, XXa Sesidn, Mexico City,
1956. Seccidn IX, Geofisica Aplicada, v. 2, 1958. pp. 243-259 ...
FOX, DENIS L. Perspectives in marine biochemistry. New York Academy of Sciences, Annals, v. 90, article 3, November
17, 1960. pps GLTSO2T Beers |, wi-<) Aiea s Wy sini Do Dag REAR ar GeO ei <
FOX, DENIS L. and FRANCIS T. HAXO. Pigments and algal commensalism in the blue oceanic siphonophore Velella lata, International Congress of Zoology, 15th, London, 16-23 July
1958, Proceedings. Section 3, Marine Zoology. pp. 280-282.....
xii
Page Number
1021
1029
1053
UNIVERSITY OF CALIFORNIA SCRIPPS INSTITUTION OF OCEANOGRAPHY CONTRIBUTIONS, NEW SERIES
‘a 1960 A
AUTHOR INDEX
ANDERSON, VICTOR C.
Eee TE DUMAIOE Socks Revrdiets o sMaalt dyieil« dow. ote bees wl
ARTHUR, ROBERT S.
A review of the calculation of ocean currents at the equator.....
BALECH, ENRIQUE The changes in the phytoplankton population off the California
Ae eRe Sa ME TL Pa ek Avec pa aras Shim) ohare PERG Tol SMO ne oko
BARTHOLOMEW, GEORGE A. (with Carl L. Hubbs) Population growth and seasonal move-
ments of the northern elephant seal, Mivounga angustirostris. . .
BERNER, LEO D. Unusual features in the distribution of pelagic tunicates in
LTS ie 2 7 pega me ie 2 ae a ti rl a ea Ae Sahl
BIEN, GEORGE S. (with Carl L. Hubbs and Hans E. Suess) La Jolla natural radio-
Se MARSA POTN EMRE ois i Gas. by a Soe har eye tea oa Ser ueret pecetet ete
BODEN, BRIAN P. (with Elizabeth M. Kampa and James M. Snodgrass) Underwater
daylight measurements in the Bay of Biscay..............
BOWMAN, THOMAS E. The pelagic amphipod genus Parathemisto (Hyperiidea:
Hyperiidae) in the North Pacific and adjacent Arctic Ocean....
BRINTON, EDWARD Changes in the distribution of euphausiid crustaceans in the re-
Peet iee MEMMAROT II CULTCNC. cs 5's t's 2 ss oe eto es we we 8
CRAIG, HARMON
The thermodynamics of sea water .......-.-.seesevceveves
CURRAY, JOSEPH R. (with Tjeerd H. Van Andel) Regional aspects of modern sedimen- tation in northern Gulf of Mexico and similar basins, and
paleographic significance. ....... 2-2 ce sever eee ccs cnes
Sediments and history of Holocene transgression, continental
shelf, northwest Gulf of Mexico.............2-ee se eeeee
* Not available for exchange.
xiii
Contrib, Number
1169
1196
1170
1158
1164
1219
1171
1197
1213
1214
Page Number
495
391
499
785
505
287
451
945
509
DAWSON, E. YALE (with Michael Neushul and Robert D. Wildman) Seaweeds as- sociated with kelp beds along southern California and north-
western MEXICO ee aera acelle hateg etiotee (otis Belraieetcstne
ECKART, CARL H.
Hydrodynamics of oceans and atmospheres........ EAA tive jl Variation principles of hydrodynamics............2.6-..-2e0%
EWING, GIFFORD C. (with Edward D. McAlister) On the thermal boundary layer of
REP OCCAN 5. shes awe diss, eins wllsiceia! oekci ai eMae shoal omens cliew eras
FAIRBRIDGE, RHODES W. (with Harris B. Stewart, Jr.) Alexa Bank, a drowned atoll on
the Melanesian Border Plateau. ..........cccccccceecses
FILLOUX, JEAN H. (with Douglas L. Inman) Beach cycles related to tide and local
WING) Wave LeOClMG | cation ks koi ucceditaiaen spon aueme wes yfoiar sien ae: ge dns (with Gordon W. Groves) A seasonal mean sea-level indicator...
FISHER, ROBERT L. (with Robert M. Norris) Bathymetry and geology of Sala y
Gonjez. Southeast, Pacific... «:,ssnsncexbns siedais tendlae sie, aan ee im oe
FOLSOM, THEODORE R. (with Govindaraju J. Mohanrao and Perrin Winchell) Fallout caesium in surface sea water off the California coast (1959-
60) by gamma-ray measurementS..........000000 eevee
(with Svante G. Nordstrom) Suggestion for eliminating pres-
sure effects on protected reversing thermometers..........
FOX, DENIS L.
Perspectives in marine biochemistry.................e00.
(with Francis T. Haxo) Pigments and algal commensalism in
the blue oceanic siphonophore Velella lata............... Pigments of plant origin in animal phyla..................
GOLDBERG, EDWARD D.
Chemists: and the oceans: ie. ee ee Ric eee eee
(with Devendra Lal and Minoru Koide) Cosmic-ray-produced
silicon =32 in ‘natures so lisand hd Wi eehes es ee ide he eee
(with Robert H. Parker) Phosphatized wood from the Pacific
SCA LOOK es oye kee ee ee oy Sse ee an ele aes a a
GROVES, GORDON W. (with Gunnar I. Roden) On the statistical prediction of ocean temperatures (with Jean H. Filloux) A seasonal mean sea-level indicator
HAXO, FRANCIS T. ‘(with Denis L. Fox) Pigments and algal commensalism in the blue oceanic siphonophore Velella lata (with Colm O’hEocha) Some atypical algal chromoproteins The wavelength dependence of photosynthesis and the role of accessory pigments
* Not available for exchange.
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Contrib. Number
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HUBBS, CARL L. (with George A. Bartholomew) Population growth and seasonal movements of the northern elephant seal, Mirounga angusti-
MOORES. cc atarg ra eae Cee AS VS SRE,
(with Robert Rush Miller) Potamarius, a new genus of Ariid catfishes from thé fresh waters of Middle America
America (with George S. Bien and Hans E. Suess) La Jolla natural
TeMIOGATPON MOGBSUPEMIENtS.”. sk ks eal otha elu y ctew ee thee
(with Robert Rush Miller) The spiny-rayed cyprinid fishes
(Plagopterini) of the Colorado River system .............
INMAN, DOUGLAS L. (with Jean H. Filloux) Beach cycles related to tide and local
Sen WOO RONG is ome. s so ee ep ess OS oe al ee
ISAACS, JOHN D.
(with George B. Schick) Deep-sea free instrument vehicle.....
(with John E, Tyler) On the observation of unresolved surface
UU RUN TREO oo os os Ab ew sal sre yd here mrthan ly waa be toy ahr 4
JANNASCH, HOLGER W.
(with Galen E. Jones) Caulobacter sp. in sea water..........
JENNINGS, FEENAN D. (with Richard A. Schwartzlose) Measurements of the California
Pe NUM ATC NCL OOD. 3g co tacs cool neat ar a aioe te le certn eg oak eGo
JOHNSON, MARTIN W. The offshore drift of larvae of the California spiny lobster
PEST US SOLELY UP TUS tes SRO HES 2 SR PRR ee rere. 2
Production and distribution of larvae of the spiny lobster, Panulirus interruptus (Randall) with records on P. gracilis
REM = bo ae hc fe. of ohcattohie nonin de’ dj lelav ike u'es Gem <cocse ear ARS
JONES, GALEN E.
(with Holger W. Jannasch) Caulobacter sp. in sea water.......
KAMPA, ELIZABETH M. (with Brian P. Boden and James M. Snodgrass) Underwater
daylight measurements in the Bay of Biscay .............
KEELING, CHARLES D. The concentration and isotopic abundances of carbon dioxide
PEI EICODNOUG 6.1.98 Hp ee CN Eels Seals Se ee wk ee
KNAUSS, JOHN A.
Measurements of the Cromwell Current.............-2002- Observations of irregular motion in the open ocean..........
KOIDE, MINORU (with Devendra Lal and Edward D, Goldberg) Cosmic-ray-
proguced silicon-32-in natures... ee ee es
* Not available for exchange.
XV
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<_ ASS ROAD ES Oe SS ROS bP Se Bee GS: Oe We he. 6 AOR Tree
Contrib,
Number
1196 1221 1172 1158
1160
1139
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1157 1195 1164 1188 1162
1191
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LAL, DEVENDRA (with Edward D. Goldberg and Minoru Koide) Cosmic-ray-
produced silicon=32 in nature.) ics sp ccc Ss fegeliaiels ‘a:'s 0 site e) wien» Be
(with David R. Schink) Low background thin-wall flow counters
for measuring beta activity of solids ................26-
LANKFORD, ROBERT R. (with Francis P. Shepard) Facies interpretations in Missis-
SippieMeltayooOniInGS se ano cd culal clue tery ce see oie om the te: oiasmce claeais Se
LASKER, REUBEN Utilization of organic carbon by a marine crustacean: analysis
with-carbon]145, od si £d.n, «. opener areas aati epee ete ker oes
LEIGHTON, DAVID L.
An abalone lacking respiratory apertures ...............-.
McALISTER, EDWARD D. (with Gifford C. Ewing) On the thermal boundary layer of the
McGOWAN, JOHN A. The relationship of the distribution of the planktonic worm, Poeobius meseres Heath, to the water masses of the North
Pacitie ee er, esos sos chore a een a eae cy perme
MASON, RONALD G.
Geophysical investigations of the sea floor................
MENARD, HENRY W.
Consolidated slabs on the floor of the Eastern Pacific ........ The Hast: Pacific’ RiS@ esos: siistivte tebtpa dee So aa view ere re ey MER Possible pre-Pleistocene deep-sea fans off central California. . .
MILLER, ROBERT RUSH (with Carl L. Hubbs) Potamarius, a new genus of Ariid cat-
fishes from the fresh waters of Middle America ..........
(with Carl L. Hubbs) The spiny-rayed cyprinid fishes (Plago-
pterini) of the Colorado River system .................
MOHANRAO, GOVINDARAJU J. (with Theodore R. Folsom and Perrin Winchell) Fall-out
caesium in surface sea water off the California coast (1959-
60) by gamma-ray measurements
MOORE, DAVID G. (with Francis P. Shepard) Bays of central Texas coast
NEUSHUL, MICHAEL (with E, Yale Dawson and Robert D. Wildman) Seaweeds as- sociated with kelp beds along southern California and north- western Mexico NORDSTROM, SVANTE G. (with Theodore R, Folsom) Suggestion for eliminating pres- sure effects on protected reversing thermometers
* Not available for exchange.
Xvi
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© 6 © Oe 8 © @ 60 6) @ Se es) 'S Sy ee ele! ea el es erel en) feute
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Contrib, Number
1165
1148
1187
1155
1141
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1190 1207 1185
1221
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1211
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Contrib,
Number NORRIS, ROBERT M. (with Robert L. Fisher) Bathymetry and geology of Sala y Gomez, eg oe ee ee er ee ope 1149 O’hEOCHA, COLM (with Francis T. Haxo), Some atypical algal chromoproteins..... 1186
PARKER, FRANCES L. Living planktonic Foraminifera from the equatorial and south- ee aren dee RG SA PAI Se ore. FS as RN a, 1181
PARKER, ROBERT H. Ecology and distributional patterns of marine macro-inverte-
rates, aoTthérn: Gulfio€ Marico .0cisk 6 ve sya A Lares rene 1218 (with Edward D. Goldberg) Phosphatized wood from the Pacific
rae sia oy os: 4-6 0 a SUR Rh ohn ROA WIR eke le 1154
PHLEGER, FRED B.
Ecology and distribution of recent Foraminifera............. 1166 Foraminiferal populations in Laguna Madre, Texas........... 1180 Recent sedimentology, northwest Gulf of Mexico; restospect and
iA te es 5a 8) che ete ane el chars! Sie Wie te oe a taker e es 1216 Sedimentary patterns of microfaunas in northern Gulf of
cig as As on 5 ale oooh Dems SUS or oI Oa Soe 1217
POOLE, DAVID M. (with Tjeerd H. Van Andel) Sources of recent sediments in the ne E Se TH BAKICON i, oor 5 uw bias, pies bt pie GaPaad asi De 1159
RAITT, RUSSELL W. (with George G. Shor, Jr.) Seismic studies in the southern
Setiternia Continental Borderland, ».10\. js) silage 65 ee Oe 1225 RASMUSSEN, ROBERT A. Low frequency wave filters employing thermistors........... i Wah Ay
REID, JOSEPH L., JR. Oceanography of the northeastern Pacific Ocean during the last Pe UMEAE ES oso 2) . a:Whs enrol eV 5d dual’ elie Ue sole AR SRAMN GS AMS eth <O ah Sfp) EIDE Ne 1174 CAN IM tis cinch eos apc A tee: sie! en abde scale ae) Re wre sua sapie site 1220
RICHARDS, ADRIAN F., Rates of marine erosion of tephra and lava at Isla San Bene- SORES INICRICO PT oho 1c” afttife)ai/sui (atte ete deel arishs) epetaTar@le «) sfareie of 1223
RIEDEL, WILLIAM R. (with John D. H. Wiseman) Tertiary sediments from the floor
RnR ICL TATU IC CAN ee, 5. Gris th afielis, <tc top Bite) 0 fs) Sree ry fe, oe Sh aMels) @ 0 oes 1222 ROBINSON, MARGARET K. Indian Ocean vertical temperature sections................ 1146 Statistical evidence indicating no long-term climatic change in the deep waters of the North and South Pacific Oceans....... 1176
* Not available for exchange.
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705
607
315
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581
543 995
1021
1017
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Contrib. Page Number Number
RODEN, GUNNAR I. On the nonseasonal variations in sea level along the west coast
of North Arieniga CP ee crt aie ates ua dponene ee a tareeee : 1204 891 (with Gordon W. Groves) On the statistical prediction of ocean: temperaturess geil: stale te arentike Ros feel elnolfemes astretatta apt 1144 119 ROSENBLATT, RICHARD H. The Atlantic species of the blennioid fish genus Enneanectes.... 1163 425 RUDNICK, PHILIP Small signal detection in the DIMUS array...........--246- 1167 487
SCHAEFER, MILNER B. New research required in support of radioactive waste dis-
OSA. hate rler chee ee ae en ee Eee Ieee lees eo Leora 1189 =6725 SCHICK, GEORGE B. (with John D. Isaacs) Deep-sea free instrument vehicle....... 1194 775
SCHINK, DAVID R. (with Lal Devendra) Low background thin-wall flow counters
forsmeasuring beta, activity of solids! @-. 37... ... <1. sie tenes 1145 135 SCHOLANDER, PER F. Oxygen transport through hemoglobin solutions............. = 1152" > 259
SCHWARTZLOSE, RICHARD A. (with Feenan D. Jennings) Measurements of the California
Current in; Mareh) 1958 575% jcatetotabatcbateretn abe tel eateter a ane, & 1193 769 SHEPARD, FRANCIS P. (with David G. Moore) Bays of central Texas coast.......... 1211 * (with Robert R. Lankford) Facies interpretations in Missis-
Sippi: Delta borings: ie) ishe: o -sweneheneasgons) vaeiel Wain cee ee ane 1165 465 Gulf Coast: barriers. (09% 2). nade hiicun at's tacepleeeee Mees eeeaaeh © leneRee. 1210 * Mississippi Delta: marginal environments, sediments, and
STOWE oh 58 eel RE Aa RU Oe aL tia ool eed ore ce tenromre eles heen 1208 * Rise of sea level along northwest Gulf of Mexico............ 1209" > 2-* Sediment environments of the northwest Gulf of Mexico....... 1202 §=873
SHOR, GEORGE G., JR. Crustal structure of the Hawaiian Ridge near Gardner Pin-
MACLOB sco ech PL EEE re ee ec ee, ae eet acer oe 1199 =©815 (with Russell W. Raitt) Seismic studies in the southern California Continental Borderland..¢ 2% «2 osmosis 1225 1053
SHUMWAY, GEORGE A. Sound speed and absorption studies of marine sediments by a resonance method--Parts-I and I] .3)) .. .. . 2... « ame suenenene i 1184 653
SIMMONS, ERNEST G. (with William H. Thomas) Phytoplankton production in the Mississippi. Delta..o.). sr oo im ree oe ne ae 1215 “3
SNODGRASS, JAMES M. (with Brian P, Boden and Elizabeth M. Kampa) Underwater daylight measurements in the Bay of Biscay............. 1164 451
* Not available for exchange.
Xviii
STEWART, HARRIS B., JR. (with Rhodes W. Fairbridge) Alexa Bank, a drowned atoll on the Melanesian Border Plateau.............. $
SUESS, HANS E. (with Carl L. Hubbs and George S. Bien) La Jolla natural RAGRGIRT DOD MOABUT OMNES ie 055 hs Gx kai onto dla & vere ROU 1158 287
TALLING, JACK F. Comparative laboratory and field studies of photosynthesis ary @ eee PimnRtomiG Gistors. os. i eevee dle as es 1147 149
THOMAS, WILLIAM H. (with Ernest G. Simmons) Phytoplankton production in the Be Ae Sr Er Reh ae ae a kee ee 1215 *
TYLER, JOHN E., (with John D. Isaacs) On the observation of unresolved sur-
og a a er i ae mn re eee 1198 805 Radiance distribution as a function of depth in an underwater ee EM ies aia asin. sw ea, Pk RON Rae pTAate eo LW ace 1151 cr
UCHIO, TAKAYASU Ecology of living benthonic Foraminifera from the San Diego, oR eT E OR Srnec laminin ste a) Cabo: wud’ orate’ Stroh guar oe as L150 = E77
VAN ANDEL, TJEERD H. (with Joseph R, Curray) Regional aspects of modern sedi- mentation in northern Gulf of Mexico and similar basins,
Me mse PSIG HAPTIT CANCE oc Spent 6 x eval hope ek sce Se 1213 * Sources and dispersion of Holocene sediments, northern
SEIN gd as as vary oo nity i x 6 Aiko lp gags eRe es 1212 * (with David M. Poole) Sources of recent sediments in the
SERRE MARS UR ATS E KSPR ACID oe oy alg Ges). ole! e's 0 eries Waele: 0: 0 lelteriaca 7 11595 3h5
VAN DORN, WILLIAM G.
Poligw=troquency miCTODATORTADN . sic. sw de ss vies ce se sale es 1206 929 Anew long-period wave Tecorder, 5... fo. ce we ce Ho eae eee 1153 265
VOLKMANN, GORDON H. (with Warren S. Wooster) Indications of deep Pacific circula- tion from the distribution of properties at five kilometers... . 1156 275
WILDMAN, ROBERT D. (with E, Yale Dawson and Michael Neushul) Seaweeds as- sociated with kelp beds along southern California and SET ALTRI CRA COt ele area 0 rie ls. 0 6), oe spdie std o 6 ovale e 8 ee 6 1142 29
WINCHELL, PERRIN (with Theodore R. Folsom and Govindaraju J. Mohanrao) Fall-out caesium in surface sea water off the California coast (1959-60) by gamma-ray measurements............ 1203 885
WISEMAN, JOHN D. H. (with William R. Riedel) Tertiary sediments from the floor Tne RCAC oe a. inl sod) oi es 0 6 0 0 0 0 8 8 8 ee 222), LOVT
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WOOSTER, WARREN §.
El NRO 5 hist. 9 8 VEEP SO OCT EE Ge, & IGE) ISNT (with Gordon H. Volkmann) Indications of deep Pacific circula- tion from the distribution of properties at five kilometers. . . . 1156 275 ZOoBELL, CLAUDE E. r Marine pollution problems in the southern California area. .... 1183 645
Reprinted for private circulation from THE JOURNAL OF GEOLOGY
Vol. 68, No. 2, March 1960
Copyright 1960 by the University of Chicago PRINTED IN U.S.A.
BEACH CYCLES RELATED TO TIDE AND LOCAL WIND WAVE REGIME}
DOUGLAS L. INMAN AND JEAN FILLOUX Scripps Institution of Oceanography, La Jolla, California
ABSTRACT
Along portions of the northwestern coast of the Gulf of California the beaches exhibit a fortnightly cycle of erosion and deposition which is related to the combined effects of the tides and the waves generated by the daily ‘“‘sea breeze.” In this area the higher waters of spring tide occur during the early afternoon when the ‘“‘sea-breeze”’ regime is strongest. This coincidence of maximum wave intensity during the times of highest water causes the position of the beach berm to follow the elevation of the envelope of the higher
high waters in a fortnightly cycle. A record of the beach cycle is preserved within the beach face by the bands of heavy minerals that are
concentrated by wave action at the level of each high water.
INTRODUCTION on the shore and by the tidal fluctuations
‘ : that cause periodic changes in sea level. An The configuration of the beach profile is eee toatitton yn the wave - determined principally by waves that break {i qq) regime, or a systematic reoccurrence between the wave and tidal regimes will produce a periodic change or cycle in the configuration of the beach. It is well known
1Contribution from the Scripps Institution of Oceanography of the University of California, new series. Manuscript received September 25, 1959.
Contributions ‘am the Scripps Institution of Oceanography, N Reproduced by Permission graphy, New Series, 1139 rr
226
that a beach cycle related to the seasonal variation in the character and direction of approach of the waves occurs along many coast lines (Shepard, 1950). In general, the beaches build seaward during the small waves of summer and are cut back by high winter storm waves. There are also shorter cycles of beach cut and fill associated with spring and neap tides, although the wave regime, which is usually more important in the ocean, frequently masks the effect of tide on the more exposed portions of the beach face.
An interesting and often very steady wave regime is created by the “sea breeze”’ which blows onshore during the warm por- tion of the day. The sea breeze is caused by unequal heating of the air over land and water. During the day when the land is warmer than the sea a pressure gradient which causes an onshore breeze is produced near the coast. The sea-breeze regime is usually best developed in latitudes of 20° to 35° where permanent large-scale circulations such as the trades are less prevalent. The sea breeze commonly sets in during the fore- noon and continues into early evening, reaching a maximum velocity during the afternoon. The sea-breeze wave regime, which frequently exhibits an annual and even a semi-annual cycle of intensity, may combine with the tidal periodicity to pro- duce a beach cycle unique to the particular combination of tides and waves. Such cycles exist along any shore when the sea-breeze regime is effective, although they are often masked by the occurrence of other waves.
WINDS, WAVES, AND TIDES AT ESTRELLA BEACH
A daily sea-breeze cycle is characteristic of part of the year in the vicinity of San Felipe along the northeastern coast of the Gulf of California, Mexico. The effect of the sea-breeze waves on the beach profile was observed at Estrella Beach, approximately " ten nautical miles southeast of the town of San Felipe during the six-day period from May 21 through May 26, 1959. This area is an excellent laboratory for studying the
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GEOLOGICAL NOTES
effect of the sea-breeze wave regime and its relation to the tidal cycle. The reason is that the area is protected from open ocean waves by the peninsula of Baja California, thus assuring that the waves are of local origin; and the area has a large tidal range so that the effect of the diurnal cycle of wave in- tensity is easily separated and observed on the beach profile. Also, the area is protected from the northwest winds by a mountain range of 5,000—10,000-ft. elevation, thus favoring the development of a strong sea- breeze regime (fig. 1).
The tidal regime at Estrella Beach is such that the higher high waters of spring tide occur during the early afternoon when the sea-breeze circulation is strongest. This co- incidence of maximum wave intensity dur- ing the times of highest water causes the beach to exhibit a fortnightly cycle which is dependent upon the elevation of the en- velope of the higher high waters. Also, the highest spring tides exhibit a semi-annual cycle such that the highest waters occur near the times of the winter and summer solstice. The reoccurrence of higher high spring wa- ters during the same portion of the day is characteristic of areas where the solar con- stituents of the tide are significant—a situ- ation which casual inspection indicates is al- most general. However, the relation between maximum sea-breeze intensity and the oc- currence of higher high water may vary any- where from full coincidence, as is the case at Estrella.Beach, to perfect opposition.
In the vicinity of Estrella Beach the tide has a pronounced diurnal inequality with a maximum diurnal range of about 23 ft. dur- ing spring tides. At the time of observations the lower low water directly preceded the oc- currence of higher high water, and the height of the higher high water exceeded that of the lower high water by about 5 ft. (fig. 2).
During the observations of May, 1959, the sea breeze in the vicinity of Estrella Beach was usually first observed about 0900, blowing from the northeast (60°) with a velocity of about 6 knots. The direction of approach of the winds rotated in a clockwise direction until about 1400, when the breeze
GEOLOGICAL NOTES
reached a maximum velocity of about 15 knots, blowing from the east-southeast (115°). After about 1600 the breeze died rapidly, reaching a calm by 1800. A similar cycle was repeated each day (table 1).
The sea breeze generated waves which on the average reached a maxifnum significant wave height of about 2 ft. with a period of 3 to 4 seconds. The highest waves observed were about 23 ft. high and were generated by a 23-knot sea breeze on May 22, which
115°
227
face and terminates in an outer bar at a depth of about 10 ft. below mean sea level. Offshore from the bar the sandy bottom has a seaward slope of about 1:20 out to depths of about 30 ft., where the slope becomes gentle. The beach is composed of coarse to medium quartz sand which is derived prin- cipally from the extensive fans that slope down from the mountains to the west. The sand on the beach face is a well-sorted coarse sand with a medium diameter of about 700
114°
H- K 4 q Ss; w Ke; ~ Tz 9;
“S ¢SAN FELIPE y= ESTRELLA
a ELEVATIONS OVER = 5000 feet
15°
BEACH
NAUTICAL MILES
114°
Fic. 1.—Location map giving position of the beach profiles shown in figs. 2 and 3
coincided with the time of higher high wa- ter of spring tide.
BEACH CYCLES
The foreshore profile at Estrella Beach is characterized by a relatively steep beach face, which terminates abruptly on a broad low tide terrace (fig. 2). The pronounced discontinuity at the toe of the beach face and the wide low-tide terrace are typical of coast lines where the tidal range is large compared with the wave height. The beach face has a slope of 1:7 and rises about 25 ft. above the low-tide terrace, which extends 4,500 ft. seaward from the toe of the beach
microns. The sand on the low-tide terrace is coarse and poorly sorted, while the outer bar is composed of fine sand.
Because a brief still-stand in the water level occurs at high and low waters, the energy of the wave action becomes con- centrated at these levels. The extreme levels represented by the higher high waters and lower low waters of the spring tides are represented, respectively, by the higher berm crest on the beach face and by the bar at the seaward edge of the low-tide terrace. Near each high water level the waves tend to form a miniature beach or step, complete with berm crest, face, and terrace. The ma-
(3)
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(4)
GEOLOGICAL NOTES
terial excavated by the breaking waves is partly carried seaward to form the terrace and partly carried on shore to the level of the maximum run-up to form the crest of the transient beach profile. The extent to which the beach is modified depends upon the intensity of the wave Action and the level of the water. The beach face is con- tinually modified and re-sorted by the action of waves superimposed on the rhythmic fluc- tuations of the tide. The effect of the waves is most dramatic when the water level is near the crest of the beach, because the beach frequently has a slight backslope so that there is no sand above to fill the ex- cavation caused by the waves. The waves
229
elevation of 11.4 ft. MSL. The combination of highest water and the 23-ft. high sea- breeze waves which overtopped the crest of the berm caused a pronounced terracing centered around the high water level. The waves produced an erosion extending over a horizontal distance of 50 ft. and caused an excavation up to 2 ft. deep under the previ- ous berm crest. A comparison of the profiles for these days shows that the sand eroded from the upper beach face was distributed in a layer averaging 0.4 ft. thick over the lower 90 ft. of the beach face, extending from 9 ft. above mean sea level to 5 {t. below, where the two profiles merge (fig. 3).
The profiles on the two days following
TABLE 1 TYPICAL DAILY WIND AND WAVE CONDITIONS, MAY 21-26, 1959 Winp Data Wave Data Direction Velocity Height Period
Hour (degrees) (knots) (feet) (seconds) Breaker Angle
Do. c suc Calm LOW: ac See, Me she no PO as <i on 330 3 EW: fo. . bk eR me hos ec Sere seem, 330 3 LO ee ae Sh cor iene
SSeS 60 6 3 13 5° open S RO te ae 110 10 1 3 5° open N a 115 15 z 4 15° open N LT at eg 110 10 2 44 20° open N re Calm 1} 5 15° open N ~ ae Calm OW, i eee a. Fe ee 1: eet Calm LOWAP (eek ee A coe ae ee
are less effective in modifying the mid-sec- tions of the beach face, and the berm crest formed there is less obvious because it tends to merge with the general seaward slope of the beach face.
The combined effect of the sea-breeze waves and the tide in modifying the beach is shown by the comparisons of the beach profile on five consecutive days (fig. 3). The first profile, that of May 21, 1959, shows the beach configuration resulting from the waves and high water on the day preceding the highest spring water. The high water level on this day was about 11.0 ft. above mean sea level, and the profile shows a slight concavity or terrace at that level, with a pronounced berm thrown up to a height of 12.6 ft. above MSL by the run-up of the waves. On the following day, May 22, the high water level reached its maximum spring
highest spring water (May 23 and 24) show a progressive migration of the sands from the lower foreshore face back to the upper, until about two-thirds of the total eroded volume has been replaced. Also by the sec- ond day (May 24) the beach in the vicinity of high water level had built out so that the slope of the beach is again approaching its maximum equilibrium steepness of about 1:7 or 8.3°. The water level on succeeding days (May 25) was too low to aid in further berm building, and the action of the waves merely resulted in a slight concavity or ter- race near the high water level. The elevation of the small terrace tends to follow the en- velope of the higher high water level.
As the tidal range continues to decrease with the approach of the neap tides, the water level becomes more concentrated around mean sea level, and the waves ex-
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230
pend their energy near the mid-portion of the beach. However, the occurrence of high water is no longer in phase with the time of occurrence of the maximum sea breeze dur- ing neap tides, so that the energy of the waves is not concentrated at a position of still-stand but is distributed over a wider section of beach; hence the waves tend to produce less striking changes in the beach profiles during neap tides. With the ap- proach of the succeeding spring tides, the relation between the maximum sea-breeze intensity and the occurrence of higher high water again approaches full coincidence and
PM 2i MAY 1959
PM 22 MAY PM 23 MAY PM 24 MAY PM 25MAY pM22 MAY
IN FEET
HEIGHT
DISTANCE IN
PM23 MAY-
FEET
GEOLOGICAL NOTES
the beach cycle approaches completion. The cycle is completed when the sea-breeze waves, riding on the envelope of the rising tide, finally overtop the highest berm and thus produce the maximum terracing on the upper beach face, which heralds the begin- ning of a new cycle.
HEAVY MINERAL BANDS IN THE BEACH FACE
The quartz sand in the vicinity of Estrella Beach contains about 5 per cent heavy min- erals, principally of the amphibole and py- roxene groups, with some olivine. These heavy minerals have a specific gravity aver-
PROFILE 25 MAY
HEAVY MINERAL CONCENTRATES
HIGHER HIGH WATER LEVEL
FE IG. 3.—Comparison of beach profiles on five consecutive days at Estrella Beach. Each survey was made following the occurrence of higher high water. A photograph of the heavy mineral band formed on May 22,
1959, is shown in plate 1.
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INMAN AND FILLOUx, PLATE 1
Stl
JOURNAL oF GEOLOGY, VOLUME 68
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GEOLOGICAL NOTES
aging about 3.2 as compared with 2.65 for quartz. In addition to being more dense than quartz, the heavy minerals are somewhat smaller and are mostly dark in color. The heavy and light minerals are easily distin- guished from each other in the,field on the basis of their color and size. ~
The smaller heavy minerals settle with approximately the same velocity as the quartz particles; however, the heavy and light minerals behave in a very different manner when moved as bed load. Because of their smaller size and higher density, the heavy minerals naturally migrate deeper into the beach face whenever the sand is stirred or when one layer of sand rolls or slides over another. Also, the larger, lighter quartz grains are more easily rolled or placed in suspension and are thus more easi- ly transported. As a result of their greater susceptibility to transport, the quartz par- ticles are moved back and forth with the cycles of erosion and deposition, while the heavy minerals become concentrated in bands within the beach face (Inman, 1953, p. 37). The relative positions of the bands of heavy minerals provide a record of the beach cycles that is preserved within the beach face. The thickness of the heavy mineral band is a measure of the amount and intensity of erosion.
The nature and distribution of the heavy mineral bands formed at Estrella Beach and their relation to the beach cycles are shown
231
in figure 3 and plate 1. The widest and most extensive band of heavy minerals formed on May 22 as a result of the extensive terracing when the waves overtopped and eroded the berm. Portions of this band were buried and preserved by the deposition associated with the subsiding lower tides. The heavy min- eral band formed on May 23 was com- paratively thin because the waves accom- panying this tide resulted predominantly in accretion. The heavy concentrate marking the still-stand for the high water of May 24 was undercut and caused to merge with that of May 25 because they occurred on the steeper portions of the beach face. Follow- ing the terracing and formation of a heavy mineral band on the steeper portion of the beach face, the run-up of the waves riding on the receding tide covers the lower por- tion with sand so that the bands dip sea- ward and into the beach face, as illustrated by the concentration of May 25 (fig. 3).
ACKNOWLEDGMENTS.—This study was spon- sored by the Office of Naval Research and by the American Petroleum Institute, Project 51, under contract with the University of Califor- nia. The writers express their appreciation to F. P. Shepard and R. S. Arthur for their sug- gestions and careful reading of the manuscript; to Paul Fleischer, Earl Murray, Wendell Gay- man, and the other members of the Oceanogra- phy 223 class for their aid in the field; and to Helene Flanders for assistance in the labora-
tory.
REFERENCES CITED
Inman, D.L., 1953 Areal and seasonal variations in beach and nearshore sediments at La Jolla, Cali- fornia: Beach Erosion Board, Corps of Engineers, Tech. Memo. 39.
SHeparp, F. P., 1950, Beach cycles in Southern California: Beach Erosion Board, Corps of Engi- neers, Tech. Memo, 20.
PLATE 1
Photograph of heavy mineral bands in the beach face at Estrella Beach. Refer to fig. 3. Scale is 6 ft. long; the right end is 50 ft. from survey “‘O”’;| eft end is down slope and toward the Gulf. Lower heavy min-
eral bands repesent previous beach cycles.
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Deep-Sea Research, 1960, Vol. 6, p. 169 Pergamon Press Ltd., London. Printed in Great Britain
INSTRUMENTAL NOTE
ve
ey Suggestion for eliminating pressure effects on protected reversing thermometers
(Received 22 June 1959)
Ir was pointed out recently (FoLsom et al., 1959) that present day reversing thermometers appear to be not entirely * protected ’ from the effects of external hydrostatic pressure, and that a correction for the error due to pressure should be considered whenever very precise measurements are to be made at great sea depths. Reasons were given for expecting an average modern protected thermometer. to indicate temperatures too high by about 0-002°C for each 1000 m increase in depth ; and it was shown that certain instruments, those overfilled with mercury and those designed with too small an air volume below the cork, could deviate because of pressure by as much as 0-008°C per 1000 m depth change.
The rate of change of apparent temperature with depth varies with the depth ; it is greatest for large depths. Its numerical magnitude depends upon difficult-to-measure details of construction, and it would be difficult to compute for any completed thermometer. Rather elaborate equipment would be required to determine this correction in the laboratory ; however, it might be determined or compensated for at sea by making two successive casts with instruments transposed as to depth. The latter procedure would result also in a precise measurement of the temperature gradient ; it is perhaps only in gradient determinations in very deep water that individual reversing thermometers must be corrected for pressure effects.
It is apparent that some slight changes in the construction of the protected thermometers would diminish the pressure error by at least one order of magnitude, making it insignificant for all oceano- graphic purposes. In the present instrument, the sea pressure is able to increase the pressure in the small volume of air confined below the cork by an appreciable fraction, because the mercury displaced by the decrease in the whole lower portion of the external shell crowds into this small air space. Obviously, means should be sought for increasing the ratio of the volume confining air to the deform- able volume. It is clear that a gas communication through the cork would provide a suitable means, because of the large space above the cork. A simple, open tube through the cork might be sufficient; and the pouring of mercury through this opening when the instrument was upset should not lead to serious new objections. Of course, the present brass fittings would have to be replaced by fittings resistant to mercury.
A much neater solution would be afforded should the maker pierce the present cork with a tube capped at the lower end, or filled with ordinary sintered glass of a pore-size allowing air to pass readily but permitting no mercury passage under the pressures involved here. It would appear that this would add only a few minutes more construction time and might even facilitate the overall manufacture and calibration since it would decrease the likelihood of a slow change in calibration due to diffusion of confined air through the cork.
Scripps Institution of Oceanography S. G. Norpstrom* University of California T. R. Fotsom La Jolla, California
REFERENCE
Fotsom T. R., JENNINGS F. D. and ScHwartz.ose R. A. (1959) Effect of pressure upon the ‘ protected ’ oceanographic reversing thermometer. Deep-Sea Res. 5, 306.
*Helsinki, Finland. UNESCO Fellow to Scripps Institution of Oceanography 1958-59.
Printed in Great Britain by The Salisbury Press Ltd., Publicity House, Wilton Road, Salisbury, Wilts. (20256) tributions from the Scripps Institution of Oceanography, New Series, , 1.1/,0 Reproduced by Permission 169
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Deep-Sea Research, 1960, Vol. 6, pp. 125 to 189, Pergamon Press Ltd., London. Printed in Great Britain
The relationship of the distribution of the planktonic worm, Poeobius meseres Heath, to the water masses of the North Pacific . A:
JOHN A. McGowan
(Received 5 January 1959)
Abstract—The distribution of a planktonic worm, Poeobius meseres HEATH, was determined from an examination of over 1800 quantitative plankton tows taken in the North and South Pacific. This distribution is compared with the distribution of water masses, as defined by temperature-salinity curves. Since the water mass concept involves a three dimensional unit of the ocean, its use in describing the environment of an animal whose distribution is also three dimensional, is preferable to the method ef comparing plankton distributions with horizontal isotherms or isohalines.
The distribution of Poeobius coincides, for the most part, with that of the Subarctic water mass and the transition region of Subarctic water, the California Current. However, a few specimens were found in the eastern tropical Pacific. A satisfactory explanation for its restricted presence in this latter area is not possible at this time, but there is some evidence to indicate that this southern segment of the population is not endemic but has been carried in from the north. If this is true, then the occurrence of Poeobius here must be accounted for in considering the sources of the Intermediate water of the area.
INTRODUCTION
THE environment of most oceanic, zooplanktonic species is generally described in terms of the temperature and salinity ranges to which the animals seem limited. But because zooplankton is distributed three-dimensionally it is frequently difficult to relate the overall horizontal distributions of species to the horizontal distributions of temperature or salinity limits. However, with the development of the water mass concept (HELLAND-HANSEN 1916, SVERDRUP ef al., 1942) it has become possible to relate the distributions of species to that of water masses. It is the purpose of this paper to present the distribution of a pelagic organism, Poeobius meseres HEATH (1930), and to compare it with the distribution of a water mass.
Poeobius meseres, a small, transparent, planktonic animal ranging in length up to 27 mm, was originally described by HEATH (1930) from Monterey Bay, California. He obtained specimens from a plankton sample taken from a depth of approximately 350 m. HEATH suggested that Poeobius was “ a connecting link between the Annelida and the Echiuroida.” Although Remane (see PICKFORD, 1947) considered it to be an echiuroid, FisHER (1946) excluded it from that Phylum. PickrorD (1947), after an intensive study of the anatomy and histology of Poeobius, came to the conclusion that it was an aberrant Polychaete. Both HEATH and PICKFORD were concerned primarily wth the phylogenetic status of this strange worm, and virtually nothing is known of its ecology and life history. The only information available on the distribution of Poeobius is the statement by PicKForD (1947) that “ Pelagic in habit, it has been taken from moderate depths off the coasts of California and in Alaskan waters,” the report by BoGoroy (1955) of its occurrence in the North-west Pacific (position not given) and HARTMAN’s (1955) report that ‘* Poeobius meseres is known only from the northern Pacific,”
125 : Cunttibutlans trom the Scripps Institution of Oceanography, New Series, 1141. Reproduced by Permission
——, G ~S
126
JoHN A. MCGOWAN
During the analysis of over 1800 plankton samples taken in the Pacific by the Scripps Institution of Oceanography, the occurrence of Poeobius was recorded. These observations were then compared with hydrographic data which had been taken at the same time and place. This comparison revealed that the distribution of Poeobius generally coincided with the distribution of the Subarctic Water Mass.
METHODS
The plankton samples used in this study came from several different cruises and expeditions (Fig. 1, Table 1). The routine sampling done by the California Co-operative Oceanic Fisheries Investigations (C.C.O.F.I.), served as a model for all of these cruises
Table 1. Plankton samples used in this study
Expeditions
Number of tows
Scripps Institution Date Depth of tows of Oceanography (m) 6 0-100 Mid-Pacific 1950 12 0-1000 or greater 55 0-140 Northern 1951 21 trawls Holiday (not used in this study) 203 0-300 Shellback 1952 15 trawls 0-1000 or greater Capricorn 1953 35 0-140; 0-400; 0-1000 143 0-150 135 150-300 38 300-450 Trans-Pacific 1953 12 450-600 16 0-1000 4 trawls 0-2000 or greater Troll 1955 85 0-300 EQUAPAC 1956 89 0-280 14 0-25 iy 25-50 14 50-75 PAS 1954 13 75-100 20 100-300 10 300-500 12 500-700 1950 to 532 CCOFI 1954 (used in this study) 0-140 CCOFI 1950 8 0-400 162 0-140 Nor-Pac 1955 30 140-280 20 0-700 162 0-140 30 140-280 Downwind 1957 20 0-560 12 0-700 or greater Tage (Hopkins 1951- Marine Sta.) 1952 8 0-700 or greater
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The relationship of the distribution of the planktonic worm, Pocobius meseres Heath 27
and expeditions (AHLSTROM, 1954). The vertical distribution of Poeobius was determined, for the most part, from the results of hauls made with an opening- closing net, one metre in diameter, adapted from that described by Leavitt (1935, 1938). This net may be towed obliquely and opened and closed at any desired depth. Occasionally a number of these nets were used in series along a cable, thus sampling several strata simulfatieously (Fig. 2).
ies
- NORPAC + EQUA PAC
* TRANSPAC p ‘ aah Pe
« TROLL D
" ‘ ---- CCOFI-AREA NORTHERN
+ SHELLBACK °
© CAPRICORN HOLIDAY
Fig. 1. Scripps expeditions in the North Pacific. Quantitative plankton hauls were taken on every station shown.
DISTRIBUTION
(1) Geographic distribution
The greatest density of Poeobius was found in the North Pacific in the region of the Oyashio and Subarctic current. Although DALes (1957) did not find it in the surface waters (0-70 m) of the California Current, it does occur at intermediate depths (400 m or greater) in this current and also in the eastern-most part of the tropical Pacific but in greatly decreased numbers (Fig. 3). It is probably present in the Gulf of Alaska but few samples have been taken from that region. Poeobius did not occur in any of the 298 plankton hauls taken from the upper 700 m of the
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JOHN A. McGOWAN
128
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The relationship of the distribution of the planktonic worm, Poeobius meseres Heath 129
Eastern or Western North Pacific Central waters, nor did JoHNSON (1956) record it as being present in the Beaufort or Chukchi seas. It apparently does not exist in any other oceans of the world.
Fig. 3. The geographical distribution of Poeobius. The numbers of organisms per 1000 m® of water
filtered by the net are shown for three strata: A, 150-300m; B, 300-450; C, 450-1600 m. By
increasing the depth of tow, the range is extended to the south in the eastern Pacific, and the abundance of Poeobius decreases.
(ID) Vertical distribution
The opening-closing net tows taken on the Trans-Pacific Expedition show that in its area of greatest abundance in the Oyashio and Subarctic current, Poeobius is most commonly found at depths ranging from 150 to 300 m (Table 2 and Fig. 6). Although no systematic use of the opening-closing net has been made in the California Current, the area has been intensively sampled with open, quantitative, one-metre nets towed at various depths (U.S. Fish and Wildlife Service, 1954). In the northern part of this region (Tables 1 and 3), Poeobius was found only in those tows that went to a depth of 400 m or more ; in the southern part, which was covered by the Pelagic
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130 JoHn A. McGowan
Area Studies (P.A.S.) survey (Fig. 1), Poeobius was found only at depths of 700m - or more. South of 20° N in the eastern tropical Pacific* it was found, with one
Table 2. Selected Trans-Pacific Expedition opening-closing series, showing depth and
temperature range of Poeobius
Depth of tow Numbers Temperature Station (m) per 1000 m3 range (°C) 25 A 0-150 0 3°5-11:2 B 150-300 170 4-0-4-3 ¢ 300-450 5 3:7-4-:0 D 450-600 5 3-4-3-7 40 A 0-150 0 1-4-9-1 B 150-300 179 3:25-3-6 GC 300-450 120 3:3-3-6 D 450-600 0 3-1-3-3 42 A 0-150 0 0-6-9-2 B 150-300 AS 0:9-3-6 & 300-450 29 3-4-3°6 D 450-600 0 3-1-3-4 46 A 0-150 0 0-7-9-9 B 150-300 135 3-1-3-35 (© 300-450 28 3:2-3-4 D 450-600 17 3-0-3-25 48 A 0-25 0 9:2-9-7 B 25-100 0 1-3-9-3 C 35-115 0 1-3-7-0 D 140-320 40 1-7-3 6 S9 A 0-150 0 5:6-14-65 B 150-300 0 4-1-5-55 (& 300-450 0 3°8-4-1 D 450-600 3 3-55-3-8
exception, only in trawls that reached depths of 1000 m or more (Fig. 3). The exception was the capture of two individuals at a depth of 300 m near Shellback Station 207 (Table 3). Wooster and CROMWELL (1958, p. 178) have pointed out that this area near the northern boundary of the Equatorial Countercurrent is characterized by very shallow thermoclines.
Relationship of Poeobius distribution to water masses
The water in the top 1000 m north of 45° N in the Pacific has been called the Subarctic Water Mass (SVERDRUP et a/., 1942, p. 712). It is generally believed that this water originates mostly from the Oyashio with some slight mixing with water from the Kuroshio Extension. As this Subarctic water approaches the North American continent it splits, some moving northward to form the Gulf of Alaska Gyre, the rest moving southward as the California Current. The temperature-salinity relationship gradually changes as the water moves south and by the time the California Current begins to turn south-west at about 25° N latitude, becoming part of the North
* WoosTeR and CROMWELL (1958) have defined this area as ‘ the region lying between the Tropic
of Cancer (23° 27’ N) and the Tropic of Capricorn (23° 27’ S) and extending westward from the coast of Central and South America to 130° W. ;
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The relationship of the distribution of the planktonic worm, Poeobius meseres Heath K3 1
Equatorial Current (Reid et al., 1958), mixing has considerably altered its properties. Ninety-seven per cent of all Poeobius caught were in hauls taken in the area of the
Table 3. All Poeobius records excepting the Trans-Pacific Expedition, the Norpac Expedition, and those reported by PICKFORD (1947)
ry . Depth of Numbers of Water Cruise Position Date haul organisms filtered Station (m) caught by net (m*) CCOFI 5201 25° 00’N 1-52 0-147 1 444 137-40 113° 25-5’W CCOFI 5004 40° 04’N 4-50 0-421 1 1668 47-55 124° 55’°W CCOFI 5004 37° 17’N 4-50 0-423 3 1945 60-70 124° 21’W IN. H. 53° 34-:5’N 8-51 0-1200 several — 155° 00’W Tage 248-B Monterey Bay 9-52 0-740 ee 4721 Tage 242-B Monterey Bay 3-52 0-910 12 4904 Tage 144-B Monterey Bay 12-51 0-980 3 4941 PAS 120-90 26° 12’N 4-54 0-900 1 209 118° 30’W PAS 130-150 22° 30'N 4-54 0-700 1 2160 121° 15’W PAS 140-180 19° 40’N 4-54 0-700 2 3475 122° 15’W SB 186-187 1°. 1-S’°N 8-52 0-938 2 — 91° 45-7"W SB 108-109 4° 04'S 7-52 0-1640 1 — 2 82° 14°W SB 207 12° 13-:5’N 8-52 0-300 2 — 106° 07’W SB 101-102 06° 58’S 7-52 0-1463 D —_ 88° 35’W
Subarctic Water Mass (Fig. 4). Temperature-salinity curves based on data taken at these stations where the depth of Poeobius capture was known, fell generally within the range of curves characteristic of this water mass (Fig. 5). Those few curves which fell outside this range were from stations on the edge of the Poeobius distribution, and even these curves indicate the presence of a certain amount of Subarctic water. Further evidence that Poeobius resides primarily in Subarctic Water is the finding, based on the results of the Trans-Pacific Expedition, that Poeobius disappeared abruptly from the plankton when the relatively sharp physical boundaries were crossed from Subarctic to Central waters (Figs. 6 and 7). On the other hand, in the areas where there is a gradual change of properties from the Subarctic Water to the California Current, the numbers of Poeobius decreased gradually (Fig. 3).
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132 Joun A. McGowan
There is some reason to believe that Poeobius might occur in the Intermediate Water of the eastern and western north-central Pacific. UDA (1938), SVERDRUP ef al. (1942, p. 716) and others have described a convergence zone at about 41° N ,between 150° and 160° E, where mixed Oyashio and Kuroshio water sinks and spreads out
4
fi z WP hs he sisi MMI ea Ay,
ye aed ay?
fe}
Fig. 4. All known records of Poeobius. Circles indicate net tows that reached a depth of 400 m or
more, triangles indicate tows that reached a depth of 700m or more. Those circles and triangles
shown in solid black indicate stations where Poeobius were captured. Open circl2s and triangles
indicate that no Poeobius were found at that station. The hatched portion of the chart is the boundary area of Subarctic and Transition Region water (SvERDRUP ef al., 1942, p. 740).
in a clockwise circulation over most of the North Pacific at depths ranging from 200 to 900 m. Although. the shallower strata (0-300 m) of this area have been fairly well sampled (Fig. 1), only 21, widely spaced tows reached a depth of 700 m or more in the eastern half of this region (Fig. 4). Poeobius was not found in any of these tows. If it is assumed that the animal would be randomly distributed at low densities the failure to find it in these tows can be used to set an upper 95 per cent contene ‘level of 1 animal per 11,548 m® of water for its density in this region (FISHER and YATES, 1938, p.1). This may be compared with an average density of 1 animal per 17 m® in the Subarctic Water Mass.
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The relationship of the distribution of the planktonic worm, Poeobius meseres Heath je 3)
If there were no further records of Poeobius, its distribution could be simply related to that of the Subarctic Water Mass. However, seven individuals were found in the Intermediate Water of the eastern equatorial Pacific. There is little doubt that some mixing does occur between this water mass and the southern portion of the California Current, but this does not seem sufficient to account for the numbers of Poeobius caught bere. The source of the Intermediate water of the eastern tropical
TEMP °C
2) =.
29 3 SUB-ARCTIC WATER ble
34 35 SALINITY (%oe)
Fig. 5. Temperature-salinity curves from stations where Poeobius was taken on the Trans-Pacific
Expedition, compared with SverDRup’s Subarctic and Western North Pacific water. Station numbers
are indicated on the fine lines. Only that segment of the curve within the depth range of Poeobius is plotted.
Pacific is not really known, but SVERDRUP suggests that it is ‘‘ formed off the coast of South America by the gradual transformation of Subantarctic water ’’ (SVERDRUP et al., 1942, p. 706). If this is true, the presence of Poeobius might indicate that it is an antitropical species (HuBBS, 1952) as are several other pelagic organisms in the Pacific Ocean. However, plankton samples taken on the Scripps Downwind Expedition (Fig. 1) and reports of the Dana (Wesenburg-Lund, personal communication) and Discovery expeditions (Monro, 1936) indicate that it is not present in either the Central Water or the Subantarctic water of the South Pacific, and TEBBLE (1958) did not find it in the Antarctic or Subantarctic waters of the South Atlantic. It seems therefore that this explanation cannot be used to account for the occurrence of Poeobius in the eastern tropical Pacific.
Another possible explanation for the presence of Poeobius in this area is that these seven individuals represent a second and hitherto undescribed species with different ecological requirements. There are however, only slight morphological bases for this
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134
JoHN A. MCGOWAN
DEPTH (m)
STATION NO.
4 #1 #6 we 19°20 2) 22 23 24 25 NORTH
ee fe p 23 |s © 9253 ¢170
33 43 95
1280 ee STATION NO. EAST 26 27 26 29 30 3) 32_33_ 34 35 36 37 38 39 40 4) _ 42_~—S 43), 44 WEST
DEPTH (m)
300 120 29
450
@ CENTRE OF STRATUM FISHED
¢
RANGE IN WHICH POEQBIUS WERE CAUGHT
Trans-Pacific sampling programme, Stations 1 to 44, showing the vertical distribution of
Fig. 6. Poeobius. The numbers to the right of the vertical bars indicate the numbers of organisms per 1000 m?. The specimens from the deepest tows on Stations 25 and 42 might have come from the shallower
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depths.
135
The relationship of the distribution of the planktonic worm, Poeobius meseres Heath
STATION NO,
WORTH 45 46 47 48 #49 50 51 52 53 54 NS N6 117 124 125 SOUTH
120 12) 122 123
ne 19
DEPTH (m)
STATION NO. Eas? 55 S56 57 S56 S59 6O 61 62 63
STATION NO. NORTH 64 65 66 67 68 9 70 SOUTH
DEPTH (m) DEPTH (m)
1000
@ CENTRE OF STRATUM FISHED
RANGE IN WHICH POEOBIUS WERE CAUGHT
Fig. 7. The Trans-Pacific Expedition sampling programme, Stations 45 to 70 and 115 to 125, showing the vertical distribution of Poeobius. The specimens from the deepest tows on Stations 49 and 59 might have come from the shallower depths.
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136 Joun A. McGowANn
suggestion. All specimens from this area were rather larger than the average of those collected in pure Subarctic water, but despite the large size of these animals, their gonads were either missing or greatly reduced in size (Table 4). These differences do not necessarily indicate that they represent a new species for the resorption of gonads and other internal organs is a well known phenomenon in invertebrates living under unfavourable conditions. One might, therefore, expect to find such a condition in Poeobius that had been carried out of their normal environment. If this explanation is correct and the Poeobius in this area are sterile expatriates from the north, our ideas on the sources of the Intermediate water of the eastern tropical Pacific will have to be reconsidered.
DISCUSSION
Few attempts have been made to relate the entire distribution of a pelagic planktonic organism to the distribution of water mass*. RUSSELL (1935 and 1939), FRASER (1939 and 1952), Pierce (1939) and others have shown that the distributions of chaetognaths and certain other organisms in the vicinity of the British Isles are related to the movements of waters from different sources and according to FRASER (1952) ‘“‘ it has now been established that the various species of Chaetognatha are associated each with a more or less specific hydrographical environment, making the group one of the foremost of the biological indicators.”” JOHNSON (1956) has shown that copepods also may be used as an aid in tracing the water movements in the Chukchi and Beaufort seas. It should be pointed out, however, that most of the species considered by these authors are more widely distributed than the limited areas they have investigated and that until all of the boundaries of their distributions are well known, it will be difficult to define in physical terms the regimen to which they are limited, or to show whether or not their overall ranges coincide with the concept of a physical water mass. HAFFNER’s (1952) study on Chauliodus is perhaps more extensive, but because he does not have accurate data on depth of capture, it is not certain that his species are really limited to the depth ranges to which he asssign them. Further, his technique of using a single temperature-salinity measurement at the presumed depth of capture is probably not sufficient to identify a water mass, for SVERDRUP et al. (1942, p. 143) have pointed out that this may be done only in exceptional cases and that a T-S curve is ‘usually required to define a water mass.
TEBBLE (1958) has reported that certain pelagic polychaetes in the South Atlantic and Antarctic oceans are limited to particular water masses, but at the time of this writing his detailed information has not been published. In a recent study on the chaetognaths of the Antarctic regions, DAvip (1958) has shown that the boundaries of the ranges of some specimens do, indeed, coincide with hydrographic boundaries and that some of these species are endemic to the Antarctic water.
While T-S relationships are used to identify water masses, this does not necessarily mean that the organisms limited to these water masses are limited by temperature and salinity alone. Water having characteristics that would fit certain points of the Subarctic T-S curve may be found in many parts of the world, and yet, so far as is known at present, Poeobius meseres occurs only in Pacific Subarctic water or in waters ‘which may have Subarctic components. There are many possible explanations but until more is known of the biology of the animal, they can only bz considered
* As defined by SveRDRupP et al. (1942, p. 143).
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The relationship of the distribution of the planktonic worm, Poeobius meseres Heath 137
Table 4. Size and gonad condition of Poeobius from the Subarctic and Eastern Equatorial regions
Station Zone Size of specimens Month Condition of Gonads een ere a eee een 18 mm ovary large 2mm P 20 mm ovary large 2 mm TP 40B Subarctic 11 mm Aug. ovary large 2 mm 15 mm ovary large 2 mm 17 mm ovary large 2-3 mm 9mm ovary large 2 mm 12 mm ovary large 2 mm 10 mm ovary large 2mm 9mm ovary large 2 mm TP 36C Subarctic 16mm Aug. specimen opaque 15mm ovary large 2 mm 10 mm = 10 mm ovary large 2 mm 10 mm specimen damaged 13 mm ovary large 3 mm 18 mm ovary large 2 mm TP 41B Subarctic 16mm Aug. ovary 1-5 mm 13 mm ovary 1:75 mm 13 mm ovary | mm 12 mm ovary ruptured, eggs diffuse in body cavity TP 47D Oyashio 18 mm Sept. ovary 1 mm 19mm Ovary ruptured, eggs diffuse in body cavity 6mm body opaque 13 mm body wall ruptured 9 mm ovary 1:25 mm TP 25B Subarctic 14mm Aug. body opaque 10 mm ovary 1:25 mm 65 mm body opaque e 10 mm body opaque 16mm ovary large 2-5 mm 10 mm ovary large 2:5 mm 8 mm ovary 1-5 mm 12 mm ovary ruptured TP 66E Oyashio 12mm Sept. ovary large 3 mm 15mm ovary large 2 mm 16mm ovary large 2°5 mm 12mm entire posterior half is Ovary Eastern 21 mm viscera degenerate, SB 101-2 Tropical Aug. gonads missing Pacific 20 mm viscera degenerate, gonads missing SB 108-9 EB TY 10 mm July much of viscera missing, gonads missing 10 mm viscera partially gone, SB 207 | ang BP) Ao Aug. gonads missing 15 mm ovary present 1-5 mm 10 mm gonads missing SB 186-7 | Ag i 10 mm July gonads missing
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138 JoHN A. MCGOWAN
theoretical. One factor which may be of importance is the higher productivity and ° standing crop of the Subarctic, California Current, and eastern tropical Pacific areas (Hotes, 1958) compared with that of the Central and Equatorial Pacific water masses (STEEMANN-NIELSEN, 1957). Thus the southward extension of the range of Poeobius from the Subarctic water mass to the California Current to the eastern tropical Pacific may have a simple relationship to the availability of food.
From the foregoing discussion it appears that water masses, as defined by hydrographers, may also exist as biological entities. The water mass concept, which defines a three-dimensional unit of the ocean, thus provides us with an opportunity to compare plankton distributions with that of circumscribed volumes of water, each of which has a unique set of physical properties.
Acknowledgements—The author wishes to thank Mr. JoHN Knauss for his suggestions and assistance. Drs. WARREN WOoSTER and E. W. FAGER also gave valuable help. This study was done under the direction of Professor M. W. JoHNsON, Scripps Institution of Oceanography. Dr. Eric BARHAM, working under the Office of Naval Research Contract N6onr 25127, provided the information
on the Monterey Bay Poeodius catches.
Scripps Institution of Oceanography California, U.S.A.
Contribution from the Scripps Institution of Oceanography, New Series.
REFERENCES
AHLSTROM E. H. (1954) Distribution and abundance of egg and larval populations of the Pacific sardine. Fish and Wildlife Service, Fishery Bull. 93, (56), 83-140.
Bocorov B. G. (1955) Regularities of plankton distribution in the North-West Pacific. Proc. UNESCO Symp. Phys. Oceanogr. Tokyo, 1955. pp. 260-276.
ae rea P. (1957) Pelagic polychaetes of the Pacific ocean. Scripps Inst. Oceanog. Bull. 7 (2), 99-168.
Davw P. M. (1958) The distribution of the Chaetognatha of the Southern ocean. ‘Discovery’ Rep. 29, 199-228.
FisHER R. A. and Yates F. (1938) Statistical Tables for Biological, Agricultural and Medical Research. Oliver and Boyd.
ae K. (1946) Echiuroid worms of the North Pacific Ocean. Proc. U.S. Nat. Mus. 96,
15-292.
FRASER J. H. (1939) The distribution of Chaetognatha in Scottish waters in 1937. J. Cons. Int. Explor. Mer., 14, 25-34.
FRASER J. H. (1952) The Chaetognatha and other zooplankton of the Scottish area and their value as biological indications of hydrological conditions. Scottish Home Department, Marine Research (2), 1-52.
ee E. (1952) Zoogeography of the bathypelagic fish Chauliodus. System. Zool. 1,
HARTMAN O. (1955) Endemism in the North Pacific with emphasis on the distribution of marine annelids, and descriptions of new or little known species. Essays in the Natural Sciences in Honor of Captain Allan Hancock pp. 39-61. University of South California Press, Los Angeles.
HEATH H. (1930) A connecting link between the Annelida and the Echiuroidea (Gephyrea armata). J. Morph. Physiol. 49, 223-249.
Teo B. (1916) Nogen hydrografiske metoder. Forh. Skand. Naturf. Mote
’ Howes R. W. (1958) Surface chlorophyll “A,” surface production, and zooplankton volumes in the eastern Pacific ocean. Cons. Int. Explor. Mer, Rapp. Proc.-Verb. 144 109-116.
Husss C. L. (1952) Antitropical distribution of fishes and other organisms. Proc. 7th Pacif. Sci. Congr. Pacif. Sci, Assoc., 3, Meteorology and Oceanography 324-330.
The relationship of the distribution of the planktonic worm, Poeobius meseres Heath 139
JOHNSON M. W. (1956) The plankton of the Beaufort and Chukchi Sea areas of the Arctic and its relation to the hydrography. Arctic Inst. N. Amer. Tech. Pap. No. 1.
Leavitt B. B. (1935) A quantitative study of the vertical distribution of the large zooplankton in deep water. Biol. Bull. 68 (1), 115-130.
Leavitr B. B. (1938) The quantitative vertical distribution of macrozooplankton in the Atlantic Ocean basin. Biol. Bull. 74 (3), 376-394.
Monro C. C. A. (1936) Polychaete worms (II). ‘Discovery’ Rep. 12, 59-198.
Pickrorp G. E. (1947) Histological and histochemical observations upon an aberrant annelid Poeobius meseres Heath. J. Morph. 80 (3), 287-319.
Pierce E. L. and Orton J. H. (1939) Sagitta as an indication of water movements in the Irish Sea. Nature, Lond. 144, p. 784.
Rei J. L., RoDEN G. I. and Wy .ute J. G. (1958) Studies on the California Current system. Progr. Rep. Calif. Oceanic Fish. Invest., 1 July 1956-1 Jan. 1958, 27-57.
RussELL F. S. (1935) On the value of certain plankton animals as indicators of water move- ments in the English Channel and North Sea. Mar. Biol. Ass. 20, 309-332.
RussELL F. S. (1939) Hydrographical and biological conditions in the North Sea as indicated by plankton organisms. J. Cons. Int. Explor. Mer. 14, 171-192.
STEEMANN-NIELSEN E. and JENSEN E. A. (1957) Primary oceanic production, the auto- trophic production of organic matter in the oceans. ‘Galathea’ Rep. 1, 49-136.
SVERDRUP H. U., JOHNSON M. W. and FLEMING R. H. (1942) The Oceans, Prentice-Hall, New York.
TeEBBLE N. (1958, July) Distribution of Pelagic Polychaetes in the South Atlantic Ocean. Nature, Lond. 182 (4629), 166-167.
Uba M. (1938) Hydrographical fluctuation in the north-eastern sea region adjacent to Japan of North Pacific Ocean. Jap. Imp. Fisheries Exp. Sta. J. (9), 64-85 (English Abstract).
Zooplankton volumes off the Pacific Coast, 1949-50. Special Scientific Report: Fisheries No. 125. U.S. Fish and Wildlife Service (1954).
Wooster W. S. and Cromwe i T. (1958) An oceanographic description of the Eastern Tropical Pacific. Scripps Inst. Oceanogr. Bull. 7 (3), 169-282.
Printed in Great Britain by The Salisbury Press Ltd,, Publicity House, Wilton Road, Salisbury, Wilts. (20253)
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PACIFIC NATURALIST
CONTRIBUTIONS FROM THE Beaudette Foundation for Biological Research
VoL. 1, No. 14 Marcu 11, 1960
SEAWEEDS ASSOCIATED WITH KELP BEDS ALONG SOUTHERN CALIFORNIA AND NORTHWESTERN MEXICO
By E. Yate Dawson, MicHaeL NEusHUL AND RosBert D. WILDMAN
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Box 482, R.F.D. 1 SOLVANG, CALIFORNIA
Figure 1. Distribution of kelp beds along the coast of southern California and north- western Mexico.
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SEAWEEDS ASSOCIATED WITH KELP BEDS ALONG SOUTHERN CALIFORNIA AND NORTHWESTERN MEXICO"
By E. Yate Dawson’, MIcHAEL NeEusHUL’, AND Ropert D. WiLDMAN*
1. INTRODUCTION
One of the ptincipal benthic marine plant communities of California is that dominated by the largest known marine alga, the giant bladder kelp, Macrocystis pyrifera. We have attempted to survey, through a portion of its range, the floristic composition of this community and to distinguish, record and characterize its prominent plants. We present here some of the results of our observations that may be useful to future investigators of various disciplines who wish to gain a general knowledge of these plants in connection with their research problems within this highly productive marine environment.
Increasing interest in the intelligent use and conservation of our marine resources has caused much attention to be focused during recent years on the near-shore marine plant communities. The development of sport fishing as a recreational asset of the nation has brought about increased interest in marine plant resources and, in particular, the Macrocystis association. Commercial interest in this remarkable plant has also grown, and a sizeable industry has developed that harvests as much as 100,000 tons of Macrocystis annually from California alone.
In accord with the growing attention given to the Macrocystis com- munity, a need has been felt for a better understanding of the types of plants that comprise it.> Many biologists interested in kelp beds have found it difficult to deal intelligently with their research problems in the absence of a ready means of identifying by name the plants with which
1These studies were aided by Contract NR104-520 between the office of Naval Research, Department of the Navy, and the Beaudette Foundation for Biological Research. A por- tion of the publication costs were also defrayed by Mr. Harold A. Fitzgerald. The field collections forming the basis of this work were made largely by M. Neushul while working for the Scripps Institution of Oceanography’s Institute of Marine Resources Kelp Investigation Program under agreement K-1 with the California Department of Fish and Game. These collections were incidental to other aspects of the planned field program and were released for study. at the Beaudette Foundation. Contribution from the Scripps Institution of Oceanography, New Series
2Beaudette Foundation for Biological Research, Solvang, California.
3National Science Foundation Post-doctoral Fellow, University of London, Queen Mary College, London, England.
4Department of Botany, University of California, Berkeley, California. ‘
5Only two reports of underwater work with SCUBA along our coast have given any account of the plant communities. The first of these lists 17 species at La Jolla, Cali- fornia, and the second briefly describes the general composition in profile of the benthic flora at La Jolla: Limbaugh, Conrad. 1955. Fish life in the kelp beds and the effects of kelp harvesting. Univ. of Calif. Inst. of Marine Resources. Multilith 55-9. 155 pp. 9 Sept. 1955. Aleem, A.A. 1956. A quantitative study of the benthic communities in- habiting the kelp beds off the California coast. . . . pp. 149-151 in, Second International Seaweed Symposium. 220 pp. Pergamon Press, London.
fontributions from the Scripps Institution of Oceanography, New Series, ,11/, 2 Reproduced by Permission
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4 Paciric NATURALIST VoL. 1, No. 14
they are concerned. It is for this reason that the major emphasis in the present work has been placed on the presentation of extensive illustrations of the prevalent plants and of a key to aid in their identification.
Through the generosity of the late Dr. Gilbert Morgan Smith, we have been permitted to draw heavily upon the excellent illustrations from his book, The Marine Algae of the Monterey Peninsula. We also thank Dr. H. E. Jaques and the William C. Brown Company, publishers of the Pictured-Key Nature Series, for permission to use illustrations from E. Y. Dawson’s How to Know the Seaweeds. Illustrations from other sources are acknowledged in the captions.
2. SCOPE AND LIMITATIONS
Macrocystis is a plant of cool to cold waters. It is abundant in the southern hemisphere where its distribution is circumpolar in the sub- antarctic regions. Under the influence of the cold Humbolt current it extends northward along the coast of western South America to within six degrees of the equator. In the northern hemisphere it occurs only along the western coast of North America, where it occupies a position of dominance over the benthic vegetation of hundreds of miles of coast. The present report is limited geographically to only a portion of this North American range where kelp beds have been studied in relative detail, namely, along the coast of Southern California and Pacific Baja California (Text fig. 1). ,
Within this restricted range the physical limitations imposed upon the present study have been such that our knowledge of the Macrocystis community remains fragmentary compared to a corresponding community of terrestrial plants. Inasmuch as a thorough description of the problems relating to these physical limitations would occupy an inordinate amount of space here, we present the following few comments only as an indication of some of the more prominent factors to which the prospective botanist- diver must become oriented because of the way in which they restrict his effective investigation of this underwater environment.
Until recent years the investigation of the vegetation of the sea floor has been confined to the use of shipboard devices, mainly the biological dredge whose blind scrapings have yielded disconnected fragments of the flora. Now we have self-contained underwater breathing apparatus, scuBA, a field research tool upon which increasing emphasis is being placed. This emphasis is certainly deserved, but it is often placed without taking into full account the limitations of the equipment as well as those of the environment itself. It must be kept in mind that the observations, collections and measurements upon which such a study as the present one is based are made by botanists working under water in a foreign environ- ment where they are subject to severe restrictions.
The most restricting factor is that of time. On land one can examine the flora of an area quite leisurely on foot or from an automobile, while
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1960 DAWSON ET AL: SEAWEEDS 5
studies of kelp beds can only be made effectively by descending from boats which are not only expensive and time-consuming to operate, but are also subject to the uncertainties of weather and the state of the sea. Even when adequate ship time is available the diver is limited by the capacity of his SCUBA outfit and, more especially, by his own physiology, to very brief periods of underwater observation.
Because of the hazards and difficulties of work under water the diver finds himself forced to spend a major part of his available time and energy on shore or shipboard in attending to the preparation, care and operation of his equipment. During the execution of a dive, safety precautions and the mandatory presence of a companion hamper orderly observations, for one must continually be aware, because of possible equipment failure, of the condition and position of the other diver, with whom little but visual communication is possible.
The most prevalent handicap underwater is poor visibility. The diver’s view of the ocean floor, already restricted by the “blinder effect” of the face plate, is often further limited by darkness or by suspended matter in the water. Thus, under a dense kelp canopy light is commonly reduced to a minute fraction of its surface value, and in the presence of heavy plankton blooms or of sediment in the water the diver may find himself surrounded by an impenetrable gray fog in which successful work is impossible.
More subtle is the effect of the water and suspended matter on the selective removal of parts of the spectrum, to the extent that the colors of various plants become deceiving or absent. Many of the plants which appear brilliantly red in sunlight are dull gray or nearly black at those depths to which red light does not penetrate. As a result of these light and color restrictions, the novice collects only those things that he can readily see, and misses many of the smaller, often abundant and important plants. These more obscure elements of the vegetation can best be collected by bringing loose rocks and shells to the surface where certain plants borne on them can then be seen.
One of the most frustrating handicaps of the marine botanist is his inability to determine readily from the surface the places on the bottom desirable for his work. This is not so true in kelp beds themselves, where the fronds rising to the surface often indicate the presence of a favorable rocky bottom, but otherwise, one often finds it necessary to engage in time- consuming exploration. A general survey of the sea floor over a large area requires repeated dives in many places to locate areas suitable for effective work.
Finally, within the kelp community, the very aspect of the submarine forest with its bewildering array of interesting and beautiful plants and animals, attracting the diver away at every hand from any attempts he may make at methodical investigation, reduces the actual effectiveness of his underwater time and his ability to recall later many details within the
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6 Paciric NATURALIST VoL. 1, No. 14
scope of his observations. This difficulty can partially be overcome by planning the dive prior to descent and making notations on plastic sheets while underwater.
Despite all of these limitations, a total of some 85 hours of underwater work, during some 240 dives on the part of the junior authors in the kelp beds of Southern California and Northwestern Mexico, has yielded suffi- cient material to provide for a presentation that. we feel may be useful to future investigators of this region.
3. THE Keep Bep
The giant kelp, Macrocystis pyrifera, grows attached to the ocean floor by a large, root-like holdfast from which arise numerous branches, called stipes. These are floated to the sea surface by many pear-shaped, gas-filled floats borne along their length. On each float is a lanceolate blade. A single stipe with its floats and blades is called a frond. Many fronds, growing from a branching system at the base of the plant rise to the surface in a tangled bundle. Upon reaching the surface they spread slightly and the blades float out to form a layer of vegetation called the canopy. From below, this canopy appears as a vast, golden-brown roof supported by many pillars. (Plate 10)
Groups of Macrocystis plants growing together are called beds. These can cover considerable areas of the sea surface. In California alone they occupy approximately 100 square miles of near-shore waters, forming narrow patches in depths of 20 to 60 feet or more along the greater part of the coast and the islands. The major beds vary from an area of a quarter of a square mile to about 13 square miles.
A kelp bed may be compared in some respects to a terrestrial forest. Like the trunks of trees the tangled stipe bundles “support” the light- modifying canopy beneath which there is often deep shade. In open areas on the bottom there may be “glades” of smaller, bottom plants, while within the dense kelp groves the bottom supports only a few shade-tolerant species. The obvious stratification present in many terrestrial forests is, however, almost absent in this submarine forest, for, except for the kelp stipe bundles, the region between the surface canopy and the bottom is usually relatively free of macroscopic vegetation. In some areas, however, young Macrocystis plants, or the large, bush-like fruiting portions of Halidrys and Cystoseira, supported yi their many small floats, extend up into this mid-water zone.
To those whose experience with kelp beds has been confined to observations only of the surface, all the beds look very much alike, but divers having seen Macrocystis in a number of localities state that no two beds have quite the same aspect. These differences, indeed, are so pro- nounced from place to place that one finds it diffictlt to diagram a generalized kelp bed. We have chosen, nevertheless, as representative of the kelp communities most frequently encountered in our area, the kelp
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1960 DAWSON ET AL: SEAWEEDS if
bed at La Jolla, California (Fig. 2). Some comparative notes on two dissimilar beds in Baja California are also given below.
It should be pointed out here, in advance of the comments on temperature to follow, that the kelp beds within the range of this study do not change gradually in species composition as one proceeds from north to south. Dye"to frequent sharp variations in coastal water tempera- tures, plants common in northern areas reappear at “cold spots” farther south, while certain species characteristic of warm areas, such as Padina durvillaei and Amphiroa zonata, occur intermittently in those southern kelp beds subject to higher temperatures. At Sacramento Reef, a marked low temperature area, northern forms such as Calliarthron cheilosporioides, Gigartina binghamiae and Botryoglossum farlowianum reach the southern limits of their distribution. At La Jolla, California, too, a few plants such as Agarum fimbriatum and Demarestia tabacoides reach their southern limits, although the flora as a whole is representative of the northwestern Baja California region. Thus, within the La Jolla bed can be found most of the species encountered in the more southern kelp beds.
A. The “typical” kelp bed at La Jolla, California Text fig. 2 As shown in the diagram, the inner kelp bed boundary is usually at
a depth of approximately 30 feet and is bounded by the feather boa kelp, Egregia laevigata, which extends on into shallow water. On the outer
EGREGIA ¥ MACROCYSTIS PELAGOPHYCUS EISENIA 7Y* PTERYGOPHORA
LAMINARIA ume
Figure. 2. Diagrammatic cross section of the kelp bed at La Jolla, California. The more conspicuous large brown algae are shown. Smaller plants forming the bottom growth were observed and collected at points A through G. The genera represented are as follows: A. Agarum, Cystoseira, Desmarestia, Eisenia, Laminaria, Leptocladia, Litho- thamnium, Pelagophycus, Plocamium, Pterygophora, and Rhodymenia, B. Corallina, Cystoseira, Desmarestia, Macrocystis, Pterygophora, and Rhodymenia. C. Botryocladia, Codium, Lithothamnium, Macrocystis, Pterygophora, and Zonaria. In the dense shade at point D. Drouetia, Rhodymenia and Macrocystis. E. Corallina, Cystoseira, Desmarestia, Eisenia, Laminaria, Leptocladia, Pterygophora, and Rhodymenta. F. Botryocladia, Callo- phyllis, Dictyopteris, Macrocystis, Nienburgia, Plocamium, Rhodoglossum, Sciadophycus. G. Car popeltis, Chaetomorpha, Cladophora, Dictyopteris, Ectocarpus, Egregia, Eisenia, Gelidium, Gigartina, Gracilaria, Grateloupia, Pachydictyon and Pterocladia. The hoti- zontal scale is greatly compressed, the total distance covered by the transect being slightly over one statute mile.
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8 Paciric NATURALIST VoL. 1, No. 14
edge the bull kelp, Pelagophycus porra, is commonly found. Both of these plants occasionally grow intermixed with the Macrocystis, but, generally speaking, only scattered individuals are present within the bed itself.
The undergrowth present in a kelp bed may be divided generally into those species which are stalked and tree-like and those that lie along the bottom. Of the larger and more conspicuous stalked forms, the southern sea palm, Eisenia arborea, and the similarly stalked kelp, Pterygophora californica, form what may be called an intermediate layer of vegetation, for their heavy, erect stipes commonly hold the fronds well off the bottom and above the mixed growth of smaller plants there. This tree-like vegeta- tion is usually sparse except in open patches or “glades” in the kelp bed.
Several other large kelps with broad, leathery fronds, such as Laminaria, Agarum and Desmarestia, are frequent to occasional in the kelp beds. In the case of Laminaria farlowii the individual broad blades may reach lengths up to 15 feet, and lie out along the bottom like large, undulate strips of leather.
The red algae comprise the greatest number of species in the kelp bed bottom community and are often present in a bewildering array of forms. The most. ubiquitous of these are the jointed coralline algae which grow even in the deep shade of the canopy. Crustose forms of coralline algae occur as pink layers on the bottom rocks and often cement together pebbles, shells, and sand to form nodules or even areas of rough “pave- ment.” The variety of animal and plant life that may exist on and within such a coralline algal crust is amazing, and the microscopic examination of a single collection can easily provide one with an afternoon’s occupation.
The plants of the bottom community vary greatly in size, and many of the smaller, filamentous or delicate forms remain invisible to the diver except on days of most brilliant sunlight and clear water. The changes in the aspect of the bottom upon the occasion of such favorable illumination are remarkable, for many plants and animals appear that cannot be seen at all under light of different spectral quality.
Some species present within a kelp bed, and most of those inhabiting the inner margins, extend shoreward into the lowest intertidal zone. Others are strictly shade forms that extend toward the other extreme into the lesser known deep zones where light limits the distribution of attached plants. Among those plants that fall into the former category (the common intertidal species) Eisenia, Cystoseira, Plocamium, Zonaria, Dictyopteris, Codium, Lithothamnium and Corallina are perhaps the most conspicuous. Those plants that exist normally at the lowermost limits of plant distribu- tion are exemplified by Drouetia rotata and Phyllophora clevelandii, which also extend up into the kelp beds but confine themselves to areas of densest shade. Only a few species appear to be found growing almost exclusively with Macrocystis. Laminaria farlowii is such an alga, found beneath the Macrocystis canopy itself, but rarely extending either inshore or to the lower limits of plant distribution: with depth.
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1960 DAWSON ET AL: SEAWEEDS 9
B. The Kelp Bed at Sacramento Reef, Baja California
The Magyocystis association at this locality presents such a dissimilar aspect to the “typical” situation in the La Jolla area that some observations made during an investigation in August, 1957, are presented. The kelp canopy here was unysually open, and seneaih it a rugged bottom of many pinnacles and dep crevasses provided great variability in depth over short distances. The average depth of the pinnacle tops was 40 to 50 feet. The abundance of animals in the area was conspicuous. Many large, colonial tunicates formed crests along the rocks. These animals were often covered by heavy turfs of the minute filamentous red alga Antithamnion. Encrusting bryozoans were present on many algae. The more luxuriant plant growth was confined to the slopes or tops of pinnacles where grazing activity of the numerous sea urchins present in the channels and lower areas was apparently not as great. Many young Macrocystis plants were observed, also confined to the tops of pinnacles. This limitation prevented the formation of dense groves, and the resulting open nature of the area allowed the establishment of an interesting and diverse bottom flora. Desmarestia munda, large foliaceous Gigartina binghamiae, Eisenia arborea, Botryocladia pseudodichotoma and Botryoglossum farlowianum grew among the Macrocystis on tops of the rocks, while vegetative Halidrys dioica, heavily encrusted with bryozoans, and grazed Plocamium pacifi- cum, Nienburgia andersoniana and Rhodymena arborescens grew along the sides of the rocks. Apparently immune to the voracious sea urchins, Corallina officinalis, Callicrthron cheilosporioides and various encrusting corallines extended down into the crevasses.
C. The Kelp Bed at Isla Asuncion, Baja California.
This bed is representative of the southernmost Macrocystis associations on this coast, in which a number of warm-water species invade the flora and present a somewhat different aspect than the association of plants characteristic of the beds farther north. The comments are from obser- vations made during the summer of 1957.
Around Isla Asuncién a heavy kelp canopy was found between the island and Punta Asuncién as well as on the west side of the island. Scattered Macrocystis clumps were observed throughout the area although they were not always visible from the surface. The dense bed between the island and the point was characterized by a heavy canopy which reduced the light on the bottom at a depth of nine meters to less than one per-cent of that present immediately beneath the water surface. The bottom was quite irregular, with clumps of rocks alternating with sand- or shell-filled basins. Coralline algae such as Corallina officinalis and Amphiroa zonata grew, along with the prostrate Peyssonelia rubra var. orientalis and Codium setchellii, under the kelp canopy where some light penetrated. These were gradually replaced along the margins of the
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10 Paciric NATURALIST VoL. 1, No. 14
sand clearings which were bordered by the ubiquitous Eisenia arborea. Desmarestia munda and Cystoseira, the latter with epiphytic Pterochondria pygmaea, were also present. In open areas where abundant light pene- trated, a luxuriant growth of Codium cuneatum, Padina durvillaei, Phyllo- spadix torreyi, Colpomenia sinuosa and Gelidium, cartilagineum occurred with the flat brown algae Taonia lennebackerae and Dictyota binghamiae.
In the dense bed on the west side of the island Macrocystis formed very dense groves, and the bottom at a depth of 40 feet was quite dark except in areas where sand troughs passed through the otherwise rocky, ridged substrate. In such more lighted places Eisenia arborea, Codium cuneatum, Codium hubbsii and Halicystis ovalis grew, while under the increasing shade of the overhead canopy these were replaced by the coralline algae, Amphiora zonata and Corallina officinalis and by Carpo- peltis bushiae, Acrosorium uncinatum, Botryocladia pseudodichotoma and Rhodymenia arborescens. The Rhodymenia persisted farthest into the dark gloom beneath the closely spaced Macrocystis stipe bundles, until in some areas no bottom plants at all could be found.
4. Factors AFFECTING THE PRESENCE AND COMPOSITION OF A Ketpe Bep CoMMUNITY
Along undisturbed portions of our coasts the Macrocystis community is distributed according to several limiting factors in the environment, some of the most obviously important being those of substrate, temperature and light. Probably the most markedly limiting of these is substrate. In occasional localities along southern California Macrocystis has been, observed to form pure stands on sandy bottoms in the virtual absence of other algae. In such places, young plants generally begin growth on worm tubes, their holdfasts spreading widely and penetrating the sand slightly. Anchorage is apparently provided by the accumulation of heavy material within the holdfast. Rocky bottoms, however, especially those constantly swept free of sediment by currents, provide favorable attachment for multitudes of plants, and it is here that the kelp community may find optimum conditions for growth in accord with the factors of temperature and light.
Temperature in the sea markedly influences the geographic distri- bution of the marine plants by governing, among many things, both the rates of the metabolic processes and the solubility of their metabolic gases. These influences are especially well demonstrated along the coasts of southern California and northwestern Mexico where sea water tempera- tures vary so markedly with coastal geography and where Macrocystis and its associated algae are such effective indicators of this variation.
It has been pointed out that Macrocystis is a plant of cool waters. The coast with which we are dealing is a cool water coast, not only because of the general southward drift of water from the north, but because of
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1960 DAWSON ET AL: SEAWEEDS a
extensive coastal upwelling of cold, subsurface water as the result of wind-created currents. Coastal configuration, with respect to the direction of the wind, governs the intensity of the cold water upwelling and the consequent temperatures of near-shore waters. We find that along north- western Baja California strong upwelling occurs all along the coast south to Bahia Vizcaino,..but is especially intense south of such headlands as Punta Banda, Punta Baja and Cabo Colnett where low temperatures favorable to the Macrocystis community are present. Bays and estuaries such as Bahia de Todos Santos and Bahia de San Quintin are separated from the open sea and, hence, show little influence of upwelling. Such locations are characterized by species of warmer areas. The huge warm water eddy which occurs in the Vizcaino Bay, where upwelling is essen- tially absent, accounts for high temperatures there and the absence of Macrocystis, while at Punta Eugenio and immediately southward, with the reappearance of intense upwelling the kelp beds appear again and continue on south to Punta San Hipdlito or beyond.
In Fig. 1, one sees the general distribution of the kelp bed community. Macrocystis has been reported as far south of Punta San Hipédlito as Isla Magdalena where it may possibly occur sporadically in areas of maximum upwelling such as off Punta Hughes. This area between Punta San Hipdlito and Isla Magdalena is, accordingly, one of transition from the cool-water flora of the Californias to the warm water flora of the Mexican tropics.
It is interesting to note that at Alijos Rocks, 180 miles west of Isla Magdalena, a Macrocystis community occurs in waters of higher tempera- ture than are normal throughout its coastal range. This seems to be due to conditions of extreme agitation and aeration which would appear to compensate somewhat for the higher temperature by providing greater supersaturation of the water with O, and CO,. At deeper levels, below this highly aerated zone, such characteristic Macrocystis community plants as Phyllospadix, Egregia, and Cystoseira are largely replaced by species of tropical affinities.
Light is another critical factor governing the structure and composition of the Macrocystis community. The effect of shade on the bottom com- munity is often quite striking.
An “ideal” kelp bed, in terms of light modification, was studied on the west side of Cedros Island in Baja California in August 1957. It had a well-developed, continuous, dense surface layer of fronds. The Macrocystis plants were evenly distributed over a smooth rock bottom bordered by sand. Penetration of light was measured in an open area adjacent to the bed where 5% of the surface light reached the bottom at a depth of 51 feet. Within the bed the attenuation of light due to the water, plus the effect of the Macrocystis plants, reduced the available light on the bottom below the canopy to less than 0.1% of that measured immediately below the surface in open water.
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Ue Paciric NATURALIST VoL. 1, No. 14
The bottom flora in the above described area consisted only of a few plants, these being relatively undeveloped. Leptocladia, Cystoseira, Prionitis, Bossiella, Acrosorium, and Lithothamnium were found. At the same depth in a bed at the San Benitos islands, where an open canopy was formed by scattered Macrocystis plants, 28 species were collected. Similarly striking differences in bottom plant abundance and diversity can also be found in different parts of a single kelp bed.
Biological activity, in particular that of herbiverous and encrusting animals, it is of great importance in the modification of kelp bed composition and structure although our present knowledge of: their specific effects is limited. The overall importance of this factor was recently demonstrated when a grounded tanker released crude oil into a small bay on the Baja California coast, killing nearly all of the animals, including the major herbivores such as the sea urchins and abalone. The great increase and luxuriance of plant growth that followed upon the removal of grazing pressure, dramatically demonstrated the important part played by these animals in the regulation of the plant association. Attempts to cultivate Macrocystis plants in the sea have also demonstrated the importance of animal activity in the establishment and growth of transplants, for grazing damage often results in their complete destruction during certain periods of the year.
5. COLLECTION AND PRESERVATION OF MATERIALS
Marine biologists working with kelp bed plants should keep in mind the great value of preserving identified voucher specimens, both in support of field observations and in connection with any experimental work which, for purposes of obtaining reproducible results, may require precise identi- fication of the organism. Preparation of specimens is relatively easy and should not be neglected.
For most general collecting, the diver will find that a heavy gauge perforated plastic bag of the type used in vascula by terrestrial botanists will serve well under water. An effective underwater collecting kit has been devised, however, which permits several collections to be made and kept separate in accord with field notes which can be made during a dive. This consists of a wire rack to which is attached a series of small bags made of fine nylon netting. The bags are closed by overlapping pieces of netting, but permit specimens to be thrust in through the slit.
Specimens may be kept in the laboratory for considerable periods in dilute formalin (about 2%) in five gallon tins. Dry specimens can easily be prepared by spreading specimens out in water in a sink, slipping a sheet of good rag-content paper under them, draining and pressing in an ordinary plant press, using cloth or waxed paper to prevent specimens from sticking to other than their backing sheets. (For full directions for mounting, labeling, sectioning, etc., see Dawson, 1956, How to Know the Seaweeds. )
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1960 DAWSON ET AL: SEAWEEDS 13
6. UsE OF THE ILLUSTRATIONS AND Keys
The difficulties of identifying marine plants have been widely acknowledged by marine biologists not trained in algology. In most cases this has been due to the unavailability of local floristic works which permit ready recognition by illustration and avoid the problems of examining internal Structures. The few well-illustrated floras which are available for the most part treat rather extensive geographic areas, include the intertidal zone, and generally contain such numerous species of diverse habitats that the algologically untrained worker finds them of little use. Inasmuch as there is no single treatment of the algal flora of southern California and northwestern Mexico, workers in this area have been particularly handicapped. They have used almost exclusively G. M. Smith’s Marine Algae of the Monterey Peninsula, California, which is excellent for the region north of Point Conception, but lacks many common and widespread species found within our southern area.
We have felt that a most useful tool for a worker in the kelp areas south of Point Conception would be a fully illustrated manual of the larger, conspicuous, sublittoral forms, selected as a result of our experience with the region to include only those that one is likely to encounter with reasonable frequency in an extensive diving program. By this reduction in the total number of plants involved, we believe that recognition of the species through the use of the illustrations and keys will be practical and relatively easy. In a large majority of cases no microscopic exami- nations need be made, and in those instances in which internal structures must be relied upon for positive identification, figures have been provided which will enable one to make comparisons by means of a hand section cut with an ordinary razor blade.
Terminology has been kept as simple as possible, and such technical terms as are used may be understood from the illustrations.
Inasmuch as the green, brown and red colors of the larger plants growing in sublittoral waters are in almost all cases readily distinguish- able (either in sunlight or artificial light)® we have employed this simple color breakdown in the key as an aid to ready identification.
KEY TO THE COLOR GROUPS
Plants distinctly green in color throughout ............::scccseseeseeeees Green Algae and Surf Grass, Key I. (text p. 26) Plants distinctly brown in color throughout .........::..:000+ Brown Algae,
Key II. (text p. 30)
Plants in principal parts reddish, pinkish or purplish (sometimes densely so and requiring that they be held up against a strong light to reveal the redness), the spores always
Re cst sage oc tvavetassaposeoseghaneviSis Red Algae, Key III. (text p. 38) ®It has not been possible to use successfully such a color breakdown in keys which
include intertidal algae, for in intertidal habitats variations in masking pigments often cause confusing color differences that complicate the problem of recognition on this basis.
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14 Paciric NATURALIST Vou. 1, No. 14
I. Key To GREEN ALGAE AND SuRF Grass‘ 1. Plants consisting of a single, ovoid cell 1g to 3%
INCh Mit si aMeL!ST ©The: cceacvys ce sees ae Nes sateseesededsesscuend Halicystis ovalis 1. Plants consisting of more complex StructuTe ...........scseseeeeeecreeeesenee RY Zo, RANTS SPOR vwesansdigpaneomivarenes sea eee ot 2 cL Ree UN NEN SE dees, 3 2. Plants with slender, elongate parts, not SPONGY ..........:esceseeseees B) 3. Plants prostrate, low, cushion-shaped .......c.cccsceseeseseseseeseeeeseteeseees 4 geo Plavitsverect;! branched? iii... cee. .. Codium cuneatum 4. Plants consisting of utricles with pitted end (walls Morris iereeatinns desiirancaes Codium hubbsii 4. Plants consisting of utricles with smooth, non-pitted walls ........:.ccssseeseees Codium setchellii 5. Plants two feet long or more, with long, slender leaves vusdicssim -pspcivopissedenpe stumnen-toterds Phyllospadix torreyi 5. Plants usually less than 6 inches long, the branches of a single row of large Cells .........:ccsccccssesseseesseseeeee 6 6. Plants branched, erect, tufted ........ Cladophora graminea 6. Plants unbranched, twining ................ Chaetomor pha torta
Il. Key To THE Brown ALGAE
1. Plants with hollow, float structures ................:ccccssssccssssnccecceseesenees z Plants without hollow, float structures ..............cccssccsssssseccecssseeeseees 7 2. Plants with a single large bulb between the long stipe and the broad blades ........ Pelagophycus porra 2. Plants with several to many float structures .............:cceeeeees 3 3. Plants with small float structures joined in series .............:ccesee 4 3. Plants with small or large individually separate floats ................ 5 4. Series of float structures, cylindrical, bead-like Bo. hs wcteneeerae ame Cystoseira osmundacea 4. Series of float structures flat ............0.... Halidrys dioica 5. Floats less than 14 inch in diameter, not bearing a leaf-like part ................ Sargassum agardhianum 5. Floats about 1 inch long or more, bearing a FGat KE Part <.:.-.00.:-veecunctetsn sees ehsncndees ture pees eee eee a eee as 6 6. “Leaves” and floats borne on either side of a flat. axis ......cseeseeaeess.snedastee ce ete Egregia laevigata 6. Leafy parts borne alternately along a cylindrical axis -...ci;24h;aeeeiaeeean Macrocystis pyrifera
"In the annotated list that follows the key, the species are arranged, for convenient reference, alphabetically by genus and species under each color group. The figures making up the plates are arranged in approximate phylogenetic order.
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1960 DAWSON ET AL: SEAWEEDS 15
7. Plants hollow, sac-like or bubble-like or convoluted v.ccccceccsescsesees 8 7. Plants differentiated into variously modified holdfast, stipe and blade parts ........s.ccccccscsssssscssssssssvsesessesessesseecesees 10
8. Plants sac-like, flattened or expanded, Te edd yl ee a RAE AoE E> Ail 9 8. Plants bfibble-like and smooth or undulate and convoluted, epiphytic or on solid P| RORY Es Ae OE CT RY eae Colpomenia sinuwosa 9. Plants commonly epiphytic on Halidrys, flat SE SIT iin AUE RON. Scania Colpomenia rigida 9. Plants commonly epiphytic on Cystoseira, more or less inflated, flabby ........0....0.... Coilodesme californica 10. Plants consisting of a single, unbranched blade (which, however, may become lacerated ................00+: 11 10. Plants variously branched and divided ..........cccceteeeeeee 17 1l. Blades with veins or midrib (sometimes only a aiftuse medial ‘thickening ) 1.5.4, junceueeeoed ih aren jatearsienssctaees 12 S17.” Geeees rwrthout midribspr veing.:.c02). AAS AS eh cds 14 12. Blades with opposite veins from a slender median vein ..............000 Desmarestia tabacoides 12. Blades with a single broad midrib ax medial thickening soo00o:.tat... adane.tel ibs ad. lala. 13 13. Blades roughly corrugated, developing performations, the stipe fringed ..........0..... Agarum fimbriatum 13. Blades smooth, marginally undulate, without perforations, stipe smooth .............000 juvenile Egregia laevigata 14. Plants large, 3-15 feet long, with leathery. blades. ..s:..65:2 Satie. 1.3 Laminaria farlowii 14. Plants small, less than one foot long, smooth, thin .........:cccccsseeseseesseeeeeeeed lest ee ntasaaders 15 15. Blades with small lobes along the DR OE RMF bo anne as 040oeon puts need juvenile Eisenia arborea 16> Blades smooth. throughout 4.123. men atlases. 16 16. Blades expanding gradually above the stipe, developing a longitudinal median slit above the stipe .... juvenile Macrocystis pyrifera 16. Blades expanding abruptly above the stipe,
not developing a slit ..............+ juvenile Laminaria farlowii iv? Plants tieedikes with’ heavy stalks .........:....sccecccecsseecesssetieeceeveceteoes 18 17. -Plants consisting mainly of flat blades «................sccsssssessesenseseneses 19
16
Paciric NATURALIST Vout. 1, No. 14
12 19,
pale
21.
2o1
23.
25. 29!
18. Stalk forked at the top, bearing two
bunches of drooping, strap-like
LAGS asacctsrtsvteneietes-osesees ene params geet pecched Eisenia arborea 18. Stalk bearing pinnate branches
at the top and ending in a
| SLE a Fis ser RR cine en Bee a Bioeng californica Plants) with: midribs orbveinsa...cci-ccteatieeeens sree eee eee ee 25 Blantsswithout:midtibs. OF VeinS:.c..c.cs-csessrescuceescesssncceseee ea aeeeeaeeee ences 20 20. Plants dichotomously branched, not markedly
broaderin»upper than in lower. partsiv,.......skartnossseestesahtenes Pall 20. Plants having more or less fan-shaped parts,
not. dichotomously .branched. :..wisls..... cst Week, meee 23 Blades with small teeth along the MAL SING. banaegdoatRS ee eRe AEE, eee Dictyota binghamiae Blades. with. smooth) margin§ js..5en0uad,, xls wnigav..4iiseeckestoctees 22
22. Plants usually dark brown, the Hihidhes
usually over 3¢ inch bacedh margins
more than 3 cells thick ................ Pachydictyon coriaceum 22. Plants usually light brown, the branches
usually less than 34 inch wide;
margins only 3 cells thick ...........0+ Dictyota flabellata Plants broadly fan-shaped, 2-4 inches wide or more, with rolled margins .............c.eee Padina durvillaei Plants not broadly fan-shaped, without rolled margins %............... 24
24. Terminal branches fan-shaped, but small,
about 14 inch broad; whole plant of
clumping? form... Rates ee aie ee Zonaria farlowii 24. Terminal parts not distinctly fan-
shaped except in young plants, the
whole plant lacerate, thin,
Plat on accent vat ciecadelaie aera eee Taonia lennebackerae Plants dichotomously branched ............ Dictyopteris zonarioides Plants pinnately branched, with opposite veins .........ccc:cccsseeeees 26 26. Flat blades 1 to 4 inches broad ............ Desmarestia munda 26. Flat blades 14 to 14 inch broad; branching
abundant anne ae ican ee Desmarestia herbacea
Ill. Key to THE RED ALGAE Plants. calcareousss:, sche ee calcareous group, see No. 80 Plants firm or fleshy, not caleareaug 32. sccunensseree teeta eee 2
1960 DAWSON ET AL: SEAWEEDS 17 2. Plants prostrate, forming flat, rounded, or lobed crusts more or less closely adherent td rds 6 fags atti ion. .dhee eked bveaniieaiid... 3 2. Plants erect or at least major parts free PRE OI Bb ey wcoiyag jas: oedapegiogesvsoonmeng bp A sony etooivsanss 4 3. Plants closely adherent, firm, somewhat BIE HATG PA LSE Bisecties secivven cs Peyssonelia rubra var. orientalis 3. Plants loosely adherent, membranous, Gelichte;: flexible \.uditviasi...ch). knw Amplisiphonia pacifica 4. Principal and conspicuous parts easily recognized as being distinctly and dais flat, or distinctly cylindrical, as am OFS OLE... 5 4. Principal individual parts of plants bat) compressed or a little or narrowly flattened, as @ , not more than about 4 times as broad as thick, as , sometimes the branching so arranged that the whole plant appears to be flat and finely dissected, but the indivi- dual parts only compressed or somewhat TL SOSA Pe keg en 5 ed AIRE ae AES RP SI 62 5. Principal parts of plants distinctly flat, with more or less membranous or thick leafy parts SUIMERG UNAS YOU. WSK ges che steerscses tng uskh rponedas -aahinnesenss 6 5. Principal parts of plants distinctly or nearly cylindrical, either coarse and obviously so, or some- times filamentous and almost microscopic (use a hand Jens on-more delicate omnes) iva.....00.cccocbdedsessvindavaceorevadsstbeccecees 45 6. Plants primarily peltate, parasol-shaped ...........cccseeeeeeeees ii 6. Plants variously branched and attached, but Oi are late i255... Ait ee ed. Sars. 8 Saat een 8 7. Blade rotate, the margin smooth .............0:0008 Drouetia rotata 7. Blade with star-like points which later form secondary attachments .............:00 Sciadophycus stellatus 8. Plants growing entangled and with frequent hook-like branches ............ Acrosorium uncinatum 8. Plants attached by some kind of basal holdfasts, WIEEOUP OOK-Like bYqnchies sh Hee EN ee seceensees 9 9. Blades with more or less conspicuous lines or veins (easily visible with no more than a SB-power hand lens) .....0.......escsscsessceseesessseessesessnensseseessseseneseneseneaes 10 9. Blades without conspicuous ribs OF VeINS «........eeeeteee TA eve 16
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18 PaciFric NATURALIST Vou. 1, No. 14
10. Blades with essentially smooth margins .......ccseeeeeeeeeees ll
10. Blades with toothed, lobed or crisped margins ..............00+ 12 11. Blades dichotomous, with a single, discontinuous
central 'rib-lite: 17 givseno creme Mbransehe eyes Stenogramme interrupta
(fetnale plants) 1l. Blades broad, fan-shaped, with many. anastomosing
WRCERLD sll src ONS, GN es ce Mat ssa ipa teaes Polyneura latissima 12. Blades with teeth along the margins> ..........ccseseeeeeereeeeees 13 12. Blades with small separate or densely crisped lobes. ‘along margins) ...poscis1ces-conuesesdenrseoamensedebeconenaces 14 13. Plants large (5-30 cm.) abundantly branched) ..tanccostecdtemeasn Sa | eink sg Nienburgia andersoniana
13. Plants small (under 4 cm.) simple or sparsely branched) li .chosis esses. aceovalic Anisocladella pacifica
14. Blades with relatively few, small, marginals lobesisac. ait, 22aiiokew... Cryptopleura violacea. 14. Blades with crisped margins consisting of densely crowded, small lobe- ke outerowths ieee Ae. aes meen cabives tesorscetastaketevartarhantanzs 15 15. Blades narrow, less than 1 cm. broad, the plants commonly under 10 cm. high; SPIPNY LG. ccaritens deco ios ceaete et neameeeh, heres aeeant Cryptopleura crispa 15. Blades broader, more than 1 cm. wide, the plants commonly 20 cm. tall or more; usually not epiphytic ............ iret Botryoglossum farlowianum 16. Plants with irregular teeth along the WHAT OVS. <..0cosssuscxvequncuseinnccetadiiesesdetase Leptocladia binghamiae 16. Plants with margins of blades smooth or with rounded protuberances, lobes, rufflés ‘or. papillae, but s10t- teeth .:...<..c2is... Soe. Mielec. skeen 17 17. Plants small, usually less than 2 cm. in height or expanse, usually epiphyBG suave .sgit quence mete lage eeealete 18 17. Plants larger, 3-60 cm. tall, usually not ppl yen’ oes c2..2.s Sue cca gaaneea ies td Saas ta ee Eat Ra a2 18. Plants always epiphytic on Phy llos pada. v.steiss aed as tedidnceaatel Smithora naiadum 18. Plants, when epiphytic, not on Phyllospadisi cma; cas wpensccn micah en tad ee eee cs 19 19. Plants with distinct midrib and lateral veins when viewed with moderate magnification ........ Branchioglossum undulatum 19. Plants without any midrib ............... Lespeyi blend munlerssnvcenldoge ee ee 20
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1960
DAWSON ET AL: SEAWEEDS
19
Zi;
21.
23.
23.
25. ri
aie yA
29.
29.
20. Plants broadly round-lobed rather than distinctly branched, one cell thick ............ Myriogramme caespitosa 20. Plants widely branched, the segments
strap-shaped, many cells thick ...........ccccccccssssessssscsescereeeesesees 21
Cystocarps bearing several crown-like points;
tetrasporangta borne embedded in the
TNA SA io csscetesvivtevestesovsevinceevenis Fauchea laciniata (small plants)
Cystocarps rostrate but not coronate;
tetrasporangia borne in open cavities
G0, SER RMU Sis bekcespesvisiseo’th biel. tmarsaienitod Binghamia forkii
22. Plants simple or very little branched ........0.cccccesescceseeeeeeees
22. Plants conspicuously and frequently branched ................6+
Surface of broad blades covered with rough papillations Or Poinked Ouubgrowihs ......16. Ae ROAAS ARITA ARG AINol nde
Surface of blades essentially smooth ............cccscccssscssssesescsestessseseseese 24. Blades very broad, 10-50 cm. a Rp BBE S dc corey genes mae et ae Gigartina binghamiae
24. Blades narrower, mostly under 7 cm. wide, SIMO sar. S0VaassavsanssucensrarTotanachitsseaeeh Grateloupia howeii
Blades very broad, rounded ...............4. Cryptonemia obovata Blades elongated, much longer than Wide ............ccccsceesseseeeeeeeeeeeeees 26. Plants purplish in color; apices tapered and
generally pointed .............:cesee Grateloupia schizophylla (non-proliferous. plants)
26. Plants rose-red; apices rounded ...... Cry ptonemia angustata Plants distinctly dichotomously branched ............:.::csssesseeeeeseeeeeseees Plants irregularly alternately, flabellately or pinnately branched, but not distinctly dichotomous ...............0+ 28. Plants with prominent marginal
AUER TO WEB coxnesen-sghoea ses igin iain UB SbaBy Se od Gigartina volans 28. Plants without prominent marginal outgrowths ................... Ultimate branches commonly becoming congested ; interior of thallus densely stuffed with filamentous RAITT ces cen raniict cesinincagnciiap assert Carpopeltis bushiae Ultimate branches not becoming congested; interior of thallus of large, relatively thin-walled cells .........:::cseseeeeneeeees 30. Upper segments expanded to over 2 cm. wide;
plants to 16 cm. high ......... Phyllophora clevelandii
30. Upper segments exceeding 1.5 cm. wide ........:ceeseeees
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Paciric NATURALIST Vou. 1, No.
14
3l.
ol.
33.
33.
Be
39.
37.
37.
39.
39.
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Tetrasporangia scattered through the cortex, without specialized sori or Other structures ..........csccsceees Gracilaria cunninghamii (in part)
Tetrasporangia borne in special sori or on special branchlets «.......0.....2:s0osensse-censoncrsesenestansMpecanennsnedtentedonenasndeesatens 32. Plants attached by a heavy conical hold.
ASE ss Rhea ond it nennsinnncdnonms nas Rhodymenia arborescens 32. Plants attached by a small disc holdfast
and often by accessory: stoloms: cvs goed. c:idsahacsee-goptestserboten-- Stolons associated with primary holdfast; tetrasporangial sori on special leaflets ...........:ccccecsesseeteeteeteeneeeeees Attachment only by primary holdfast, without stolons; tetrasporangia borne in irregular sori on middle blade surfaces ..............:0:006+ Stenogramme interrupta
34. Terminal segments attenuated or
narrowed below tip ........scccsssereseees Rhodymenia attenuata 34. Terminal segments rounded, not attenuate .........cceeeeeees Tetrasporangia borne in small terminal sori; plants small, usually under 5 cm. | Ge ae ae et eM a DST DS 8 SR Rhodymenia californica Tetrasporangia borne in special leaflets; plants larger, usually, over, Gvem, tall... sc.-.....astateaiiet ewer t-stnvaaties
36. Stipe simple, short, with few stolons;
tetrasporangial leaflets from uppermost
SEPMERE WIATOINS wid der scecrannecsn cee Rhodymenia pacifica 36. Stipe short, sometimes branched, usually
with conspicuous stolons; tetrasporangial
leaflets from older segments .... Rhodymenia palmettiformis Plants with prominent marginal outgrowths, proliferations or piniiaé SES GUet ee eee eee: Plants with essentially entire segments and without prominent marginal outgrowths, proliferations .or,.pinnae <iwinnsn shixcapsoien deeming eipe eh ..een
38. Plants soft and slippery ................ Grateloupia schizophylla (proliferous form) 38)'"Plants* coarse; sti ff-<-cetccsscieterremtceennes Gigartina volans (in part)
Primary blades long, slender, strap-
shaped =.i.:., s:iin.cgeth Ree Prionitis andersoniana Branching frequent throughout; eae long
strap-shaped parts
TOPO Pee O ee meee eee eres see eee eH eee ee ee eee eee ee ees ee eEE eee sSeesesseseseeees
1960
41.
41.
43.
45.
45.
47.
47.
49. 49.
DAWSON ET AL: SEAWEEDS 21
40. Central medullary tissue composed of large, thin-walled -eells,jof uniform size 4\iss:.s.scbeavbeadeiviptvirssnestnes... 41
40. Central medullary tissue composed of mixed largicianid ‘amiallcells «4.56460 RR A 43
Plants soft, flabby, without a prominent PSII UGAY URIEI HER cote ok nace reusd cceccns tas vactbesshccetoherteac tb litroticasal. the: 42
Plants coarse, rather stiff, with flat branches from a cylindrical, branched stipe ........ Phyllophora californica 42. Plants slippery; branching widely divergent;
RPROCRIDE DOTOURIG crea castaciorpentansties: Fauchea laciniata
42. Plants not slippery; branching irregular to dichotomous, but not widely divergent;
cystocarps domoid ..........cceeeeees Gracilaria cunninghamii Cystocarps borne along margins ee ae aR ae dal Sa Callophyllis marginifructa Cystocarps borne over surface of blades ..........ccsccsesseseseeseeeeseeeeateee 44,
44. Cystocarps rostrate 1.0-1.5 (2.5) mm. diameter; segments mostly 0.5-1.5 cm.
OE oe ane | ee ot OEE RS Callophyllis megalocarpa 44. Cystocarps non-rostrate, 0.6-1.2 (1.5) mm. diameter;
segments mostly 1-7 mm. broad ........ Callophyllis violacea Cylindrical axes bearing swollen branchlets of much larger diameter than their OWN .........csccsesseescseesseseeeeseeee 46 Plants without inflated vesicular branchlets ...............cecseseeeeeeee 47 46. Inflated branches many, small, on long
branched $ stalks ooo... .cesesseseeeeeees Botryocladia neushulii 46. Inflated branches few, large, on short branched
2 LONER Fae oe ae Oe Botryocladia pseudodichotoma
Main axes bearing short branchlets which are hollow and divided by transverse partitions into a series of compartments ............ Gastroclonium coulteri
Special hollow, compartmented branchlets absent .............0::000+ 48 48. Plants relatively large and coarse, the main branches well over 1 mm. in diameter ..........:.s:0ce00 49
48. Plants relatively small and delicate, or at least the main axes mostly under 1 mm.
NN er os acres ss anges ape snch nodvd ones sssimesserguazies 55 Pas AIOUOTIOUSIY DUATIGROU |<. .ccss.t0n0rnnraconesddasesciorsessnnasiseenesaacnehs 50 Plants variously branched but not dichotomous ..........se0 51
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22 Paciric NATURALIST Vou. 1, No. 14
50. Outer cortex composed only of a layer of
large colorless cells with numerous slender
2-3-celled filaments between them ........ Scinaea johnstoniae 50.. Outer cortex consisting of a layer of large
colorless cells with numerous slender 2-3-
celled filaments between them ............ Gloiophloea confusa 51. Plants with frequent twining or hooked PTC pe hot oc att 3s - stud amneat boosie Laurencia subopposita 51. Plants without twining or hooked branches .........:.scscseessesseseeseeee 52
52. Plants with long, indeterminate branches throughout, without irregular or tufted
short branchlets® fics, accesses onde Agardhiella coulteri 52. Plants with many very short branchlets or papillae or tufts of short branchlets ............:::ccsceecseesseeeeeeees 53 53. Tufts of short branches borne on long, smooth, SIENGeN. MAI BY ANCHES | occa nc esecescteesensn a dies Chondria nidifica 53. Short branchlets and papillae scattered over Upper. parts.of, Plants jie .scceegs--cresdpdeednnadnevadpreoanemeenniayssahepass 54 54. Plants short, 8-12 cm. high, the main axes with short segments ............:00000 Gigartina canaliculata
54. Plants long, lax, 15-30 cm. long, the main axes with infrequent branches, the
ségments: Ong (ich ieedbs.vetvel lamar eannosasits Gigartina serrata So. All. branches isimilar <:iaaiwecd: ek iitsck eae eae tah deh legate neon 56 59. Main axes bearing tufts of minute hair-like lateral -branches).....c:.cciueheae eke Pogonophorella californica 56. Branches consisting of a single row of large cells ................ 57 56. Branches consisting of five or more rows of cells ................ 58 57. Plants resembling tufts of fine red PAI o..coseSdhsveccses est fa dee nan ORME Spermothamnion snyderae 57. Plants clumping, not hair-like .............0. Griffithsia pacifica 58. Plants coarse, wire-like, to 20: cme high*or more Ne. eee Gelidium nudifrons 58. Plants delicate, under 10 cm. high, soft and ‘Limp.)....:iti.cs...ccgde\ LOS MAM i, I eee cd 199 59. Plants dichotomously branched ................ Ceramium pacificum 59. Plants irregularly alternately branched ...............sccsccscsssssssossseseeee 60 60. External cells in uniform transverse tiers ........c:cceecsssecees 61
60. External cells irregularly arranged, not in tiers ach a ee Chondria californica
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1960 DAWSON ET AL: SEAWEEDS 23
61. External tiers of cells consisting
OE | SESE Os, te Polysiphonia mollis 61. External tiers of cells consisting
ar Polysiphonia johnstonii
62. Principal branching dichotomous .........c.ccccsssssscssssesssessseeevereee 63
62. Branching mainly pinnate or irregular ......ccssssssesseseeesseees 64 63. Dichotomous branches bearing short, pinnate
secondary lateral branches. ..........:cccccceseeees Prionitis cornea 63. Dichotomously branched
ERO MNIN bagkcdsivisareyseshcenssisseen Pipe Gymnogongrus leptophyllus
64. Plants coarse, at least in lower parts, seldom
epiphytic; ultimate branchlets coarse, at
least not reduced to almost microscopic SiZ€ .......s.c0cseceeseeeeseeees 65 64. Plants delicate throughout, usually
epiphytic; ultimate branchlets very
PRIG I Up MUNG OTANI 55 c9e cnn case de tin diospasetesesdneavens 74 65. Plants composed of compressed or flattened parts ETS BE 1 A RR RR AER So 2 < eee OP Ae 66 65. Plants composed of flat blades with irregular teeth along the margins ...........0:ce Leptocladia binghamiae (in part)
66. Upper branching very dense, in one plane, feathery, with many regularly curved branchlets, pectinate ..........0cccee Plocamium pacificum (in part) 66. Upper branching not particularly feathery, not pectinate; branchlets not regularly curved ..............00 67 67. Main axes with series of short, determinate MMIRTIME'Y “PTB CES yo, 525k cons 5 erinanspaney rian Prionitis lanceolata 67. Main axes repeatedly branched in successive orders, without series of short, determinate branchlets ............cccccccccceeeees 68 68. Ends of branches with a dimple-like terminal depression in which the growing point is located ................ 69 68. Ends of branches without a terminal depression ................0. 70 69. Main axes to 5-6 mm. wide; plants to 20 cm. high roy Rh Mr CEeDRS Peg SER SEER BSE ETE TP Rent es CERO RED Laurencia diegoensis 69. Main axes usually 2-3 mm. wide; plants 5-10 cm. IEE Mere encracas tees spent cate cosoasesop en vtsnb Laurencia splendens k (in part) 70. Ends of branches with a distinct terminal Se MAE OM DACRILY CWIGTIIE )) cacvnnn.n0seincducscsnseseoseveaerecnerenstavnseees 72 70. Ends of branches without a distinct terminal cell; mature plants with spiny outgrowths .........:cceseeee 71
24 Paciric NATURALIST Vou. 1, No. 14
71. Plants short, 8-12 cm. high, the main axes with short sepments /o.i.sensmeetecnesnecrenet Gigartina canaliculata
71. Plants long, lax, 15-30 cm. long, the main axes
with infrequent branches, the segments Longe a ie renee rae alee ‘Gigartina serrata
72. Young branchlets not geniculate; mature - parts often with terminal branches reduced in diameter and becoming entangled; cystocarps wnilocolar icine. 44. 2aneeee Pterosiphonia pyramidale.
72. Young branchlets at first geniculate; mature parts with branches more or less uniform throughout; cystocarps
bilocular) 22... 2B pat CECE GAA IA reeset iasins 73 73. Tetrasporangial branchlets with cordate EPICS ook ca hointecrness eguclenaaonks Gelidium cartilagineum var. robustum
73. Tetrasporangial branchlets blunt or subacute, POESCOTO ALE: ew.crasrrh nt viuerer Mo ast eepeae: Gelidium purpurascens
74. Ends of branches with a dimple-like depression in which the growing point is located tite) an vicsuseiieste enc, hee ene Laurencia splendens (in part) 74. Ends of branches acute or at least without axdimple:likedepression x .1.:5.: «act aAadi memes idenedees semen cers: teh 75
75. Ultimate branchlets with cells in regular tYAHSVERSE CEVS ..2.5cc-\ugsc eos eee meee ota eae ema cate ees, een ett Ie Le a 75. Ultimate branchlets with irregularly arranged cells not. inj tiers, ..2.-c8 coer ctaee er en te ee 76
76. Branching regularly alternate, disti-
NOUS! 200.0) achbaearra ena raat amen, Microcladia coulteri 76. Branching appearing irregular, but in one plane; ultimately pectinate ................ Plocamium pacificum (in part) 77. Erect branches without percurrent axes; commonly epiphytic, on CyStOStre cies nis sactecr edt ieciarna eae Ree ee 78 77. Erect branches with percurrent axes; variously epiphytic or saxicolous , ....esssorserasudon:-chaayaeeeen sean ee eee 29 78. Plants less than 2 cm. tall ............ Pterochondria pygmaea 78. Plants usually over 5 cm. tall ............ Pterochondria woodii 79. Older branches completely corticated ........ Pterosiphonia baileyi 79. All branches uncorticated .............0000 Pterosiphonia dendroidea
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1960
DAWSON ET AL: SEAWEEDS 25
81. 81.
83.
83.
85.
85.
87.
87.
89.
89.
91. 91;
Calcareous Group
SMP R RSIS CKUBOGES OL JOUUE ..,.......,.5c00sssyacwerecrageriotnpiinetionaees 90 DO. £e Wnbe i ointed, cRame|nted | ...ccinsssaucsererenroarenctardinuincrintyitnctersess 81 Plants with terminal conceptacles ..............sssssssssssesnsssssceseoeeees boigres 82 Plants withett terminal conceptacles ....cccsccsssesssesessesssestesseessen 86 82. Plants large, coarse, the segments 4-6 mm.
eee ee: kt Se em) 83 82. Plants smaller, the segments less than
eI ERE lon ected cosh Cap rrcurp eihes tes mir stint sieved Stas 84. Plants with flat segments throughout upper ce oe eae ee ee ee Calliarthron cheilosporioides Plants with flat segments in mid-parts and cylindrical segments in upper parts oo... cece Calliarthron regenerans 84. Tetrasporic conceptacles normally antenniferous,
at least predominantly s0 ..........ccee Corallina gracilis 84. Tetrasporic conceptacles normally non-
antenniferous, at least predominantly so .........cccssseeeeeeeeeees 85 Segments of main axes mostly .75 mm. broad PERO. LOWE bose Becs esto het Corallina vancouveriensis Segments of main axes mostly 1.1-1.3 mm. broad and CS-1.7 mms long anc... Corallina officinalis var. chilensis 86. Segments mostly dorsiventral, not
BOT Bits Slt > crac. cusp bs Amphiroa dimorpha 86. Segments not dorsiventral; plants erect ....:...ccseeseeeeeeteeee 87 Upper segments faintly banded; some PREIS DENNEN Foo iA pestis aste es Amphiroa zonata Upper segments not banded; segments 08 ENTS OR Si aes ete AREY A Sl ERR Wee a: RAP et 88 88. Segments mainly cylindrical,
EN eS: DOES Ree ee aS ete Lithothrix aspergillum Seb eee gchaR ah WAIT gn asec sence aeeae bie way bdeniestoangee de rpeverense 89 Segments arrow-head shaped, with acute NRE ance 1s bE TII Ns Bh. BOs wah Relote Bossiella orbigniana Segments wing-nut shaped, with oo TE od Ie Me Bossiella gardneri 90. Plants growing on Phyllospadiz .......... Melobesia mediocris 90. Plants growing on various algae, rocks or shells ...............0. et Plants solid, usually massive, with protuberances ...........:eee 92 Plants thin, crust-like, smooth, or at least RNIN ooo FF -sodsoanssoanseis oases cyst ecb nseib booths sveasi ieee RNa dae 93
26 Paciric NATURALIST VOL. h No. 14
92. Protuberances large, 10-15 mm. high,
5-15 mm. in diameter ................ Lithothamnium giganteum 92. Protuberances small, often low, 2.5-5 mm. in diameter, 2-10 mm. high ............ Lithophyllum imitans 93. Plants shingle-like, on rocks, shells or ‘ lower parts of some algae ............ Lithothamnium lamellatum 93. Plants growing as a crust over the surface of NATO Uli MERE co cice fseceethn as ad dee Sete v sd ciceps ees Dermatolithon dispar
SPECIES “LIST
FLOWERING PLANTS
Phyllospadix torreyi S. Watson Torrey’s Surf Grass Pl. 1, fig. 1.
Northern California to Isla Magdalena, Baja California. This is one of two species of Surf Grass that occur along our Pacific Coast. It grows on rocks from intertidal levels down to as deep as 50 feet. The long, slender, almost filamentous grass-green leaves distinguish it readily. The other species, P. scouleri, is usually confined to the surf zone and has thinner, shorter leaves and shorter flowering stems.
GREEN ALGAE Chaetomorpha torta (Collins) Yendo PI. 2, fie. ake Southern California to Isla Magdalena, Baja California. Grows entwined around other algae in the intertidal zone to a depth of 30 feet. The plant suggests a bluish-green colored tendril. Its large cells are clearly visible to the naked eye. Cladophora graminea Collins Pl. 1, fig. 4. Central California to Isla Magdalena, Baja California. Grows as small green tufts of rigid, erect filaments 2-3 inches tall, usually in areas around sand. Occasion, from intertidal to 75 feet. Codium cuneatum Setchell and Gardner of lee ah ra Southern California to Isla Magdalena, Baja California. This is a spongy, green plant, 10-12 inches high. Common in depths of 30-60 feet. Codium hubbsii Dawson Pia tig: 6 Northern half of Baja California. Forms a greenish-black, spongy patch, 2 inches or more across, on rocks, commonly under the kelp canopy in areas of encrusting coralline bottom at 30-75 foot depths. Distinguished from the next species only by the end-walls of the club-shaped utricles of which the surface of the spongy thallus is composed. Codium setchellii Gardner Ploy figs 2. ie Alaska to central Baja California. Of the same habit and habitat as C. hubbsii and macroscopically indistinguishable. Halicystis ovalis (Lyngbya) Areschoug isa a OE ai Alaska to central Baja California. This plant grows as a all: dark green ball, half an inch or less in diameter, on encrusting calcareous algae from intertidal to 75 foot depths. It appears almost black in deeper water and is seen with difficulty.
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PLATE 1 Fig. 1. Phyllospadix torreyi, flowering, X 0.5. Fig. 2-3. Codium setchellii: fig. 2, habit, x 0.5; fig. 3, detail of utricles making up exterior of thallus, showing non-pitted end walls, x 28. Fig. 4. Codium hubbsii, detail of utricles showing pitted end walls, X 28. Fig. 5. Halicystis ovalis, showing attached habit of plant, x 2. Fig. 6. Cladophora graminea, upper portion of plant, showing branching, x 6.
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PLATE 2
Fig. 1. Chaetomorpha torta, showing twining habit and large cells, x 3. Fig. 2-3. Dictyota binghamiae: fig. 2, habit, showing teeth along the margins, x 1; f section of blade, x 80.
«3, €ross-
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PLATE 3
Fig. 1-2. Pachydictyon coriacium: fig. 1, habit, x 0.5; fig. 2, cross-section of a frond showing the character of the cells at the margin, X 125. Fig. 3. Dictyota flabellata, portion of frond, x 0.5. Fig. 4. Dictyopteris zonarioides, cross-section of frond show- ing the thick midrib, superficial reproductive bodies and portions (shortened) of the blade, x 45. (after Setchell & Gardner)
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30 Paciric NATURALIST Vou. 1, No. 14
Brown ALGAE
Agarum fimbriatum Harvey 1.20, fig. 1. Southern British Columbia to southern California. The blades are light to dark brown in color, irregularly corrugated and sometimes with holes. A conspicuous midrib is present, and the ‘stipe is fringed. In our region growing at depths of 40-100 feet. ‘ Coilodesme californica (Ruprecht): Kjellman Pl. 9, fig. 3. British Columbia to central Baja California..Plants hollow, light olive tan in color, somewhat wrinkled when older with terminal portions of the sac-like plant body becoming worn and eroded. Growing on upper portions of Cystoseira plants within about 10 feet of the surface, although the host may be attached at depths of 30 feet or more. Coilodesme rigida Setchell and Gardner P6, fig22. Southern California to central Baja California. Plants dark brown in color, conspicuously flattened, with a thickening near the margins; small, usually about an inch long. Growing attached to upper portions - of Halidrys, usually within 10 feet of the surface, although the base of the host may be attached at depths of 30 feet. . Colpomenia sinuosa (Roth) Derbés and Solier Pl. 9, figs. 1, 2. Alaska to Costa Rica. These hollow plants may be epiphytic, small, and bubble-like, or larger, 2-6 inches in diameter, rough and warty, and broadly attached to rocks. Intertidal to 60 feet. Cystoseira osmundacea (Turner) C. Agardh Pl. 14. Oregon to Punta Abreojos, Baja California. The basal portions, habitat and stature (to 20 feet tall) are similar to those of Halidrys from which it is distinguished by its conspicuously rounded vesicles in bead-like series. Common, intertidal to 100 feet. Desmarestia herbacea Lamouroux Pl...7, fig, 2. Alaska to central Baja California. Plants light brown, with a con- spicuous axial vein running to branch and axis tips, profusely branched, highly acid and sour to the taste. Occasional, intertidal to 30 feet. Desmarestia munda Setchell and Gardner id Ow iy Fre British Columbia to Punta Pequefia, Baja California. Plants light to dark brown, sparsely branched, all the branches stipate at base. The characteristic long blades are often so eaten back by grazing organisms as to lose their distinctive, strap-shaped appearance. Strongly acid to the taste. Frequent in depths of 20-60 feet. Desmarestia tabacoides Okamura Pl..8. Santa Cruz Island, California to La Jolla, California. This strictly sublittoral plant occurs only in depths of 50-135 feet where it appears almost black. Its thick frond contracts to a short stipe at the base and in older individuals is often divided into two main segments. The veins are distinctive but faint.
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PLATE 4
Fig. 1. Zonaria farlowii, habit showing concentric hair lines, x 1. Fig. 2. Dictyopteris zonarioides, habit showing distinct midrib, x 1.
(59
PAGES
Fig. 1. Zonaria farlowti, upper portion of blade showing sori and hair lines, x 3. Fig. 2. Codium cuneatum, habit showing flattened forks, X 0.5. Fig. 3, Padina durvilliae, habit, holdfast and upper fan-shaped parts, x 0.5.
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PLATE 6 Fig. 1. Taonia lennebackerae, habit, x 0.5. Fig. 2. Coilodesme rigida, habit, showing plants epiphytic on Halidrys dioica, X 0.5. Fig. 3. Macrocystis pyrifera, a juvenile plant showing initial split, * 0.25.
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34 Paciric NATURALIST Vou. 1, No. 14
Dictyota binghamiae J. Agardh. PI <2, fig, 2k
Central California to central Baja California. This brown, dichotomous plant is readily recognized by its small, inconspicuous marginal teeth. Occasional at depths of 30-115 feet.
Dictyota flabellata (Collins) Setchell and Gardner Pla 3s fig. 3.
Southern California to central Baja California. Among the smooth- margined, dichotomous brown algae, this one is distinguished by its small size (3-5 inches high) and blades only 3 cell layers thick. Occasional, intertidal to 75 feet. ;
Dictyopteris zonarioides Farlow Pl. 3, fig. 435 Plat dig. 2,
Southern California to southern Baja California. Although brown in color overall, these plants often exhibit conspicuous blue irridescence in the terminal expanded blade parts. A conspicuous midrib is distinctive — and runs to the very ends of the branches. Intertidal to 115 feet.
Egregia laevigata Setchell Feather Boa PL13}fig. 1-3.
Southern California to central Baja California. This is one of the commonest and best known of the large brown kelps on account of its distinctive paired rows of “leaves” and bladders on the long flat axes. Intertidal to 30 feet, seldom deeper.
Eisenia arborea Areschoug Southern Sea Palm Pl. 16,:fige2, 3.
Southern California to Isla Magdalena, Baja California. These dark brown, tree-like plants have their blades borne in two conspicuous groups at the apex of a stout stipe. Common, intertidal to 115 feet. Plants in deep water or dense shade have more conspicuous marginal teeth on the blades.
Halidrys dioica Gardner Pl: 15, tig 1522. Southern California to central Baja California. Plants light to dark brown in color, 3 to 20 feet tall, at depths from intertidal to 75 feet. The basal blades of this and the next species are usually quite rigid. The pod-like series of flattened vesicles clearly distinguish this plant from Cystoseira. Short, sterile, vegetative plants of Halidrys and Cystoseira occur at depths of 50-100 feet, and cannot be distinguished in the absence of the distinctive float-bearing portions of the plants. Laminaria farlowii Setchell Pl. 9, fig. 4, 5. Central California to northern Baja California. Plants with a single. dark brown, thick, undulate blade reaching lengths up to 15 feet. Common in the kelp beds at La Jolla where it forms a dominant part of the bottom community. Macrocystis pyrifera (Linnaeus) C. Agardh P1..6,-ti8. oso. 10: Monterey, California to Punta San Hipélito, Baja California, intertidal to 100 feet. The plants from La Jolla southward are characterized by relatively few, heavy haptera arising from the erect basal branching system. Plants from Palos Verdes, California, northward generally having haptera arising from a basal branching system which becomes prostrate.
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=
f plant showing profuse branch-
upper portion of plant showing distinct toothed margins,
x 0.33. Fig. 2. Desmarestia herbacea, upper portion o
Fig. 1. Desmarestia munda, ing, xX 033%
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PLATE 8 habit, showing prominent central vein and faint laterals, x 0.5.
Desmarestia tabacoides,
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_ =<
PLATE 9 Fig. 1-2. Colpomenia sinuosa: fig. 1, habit of free-living plant, x 0.75; fig. 2, epiphytic habit, x 0.75. Fig. 3. Coilodesme californica, on tip of branch of Cystoseira osmundacea, X 0.5. Fig. 4-5. Laminaria farlowii: fig. 4, entire plant, x 0.25; fig. 5, juvenile plant, x 0.25,
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38 Paciric NATURALIST Vou. 1, No. 14
These may be recognizable as a different species, Macrocystis angustifolia, according to the most recent taxonomic treatment. Pachydictyon coriaceum (Holmes) Okamura Bb, oeeties. (1; °2. Southern California to southern Baja California. Similar to Dictyota flabellata, but darker brown and coarser, often a foot high. Its blades are 5 or more cell layers thick at the margins. Frequent, intertidal to 65 feet. Padina durvillaei Bory il se tS Vicinity of Bahia Vizcaino, Baja California and southward. The conspicuous inrolled margins of the coarse, ‘broad, fan-shaped blades clearly set this plant apart from other species of our coast. Common, intertidal to 40 feet. Pelagophycus porra (Leman) Setchell Bull Kelp or Elk Kelp Pl 2 tiget 12 Southern California to central Baja California. Plants reaching 100 feet in length, with individual blades up to 14 feet long, chocolate brown in color, arising from depths of 40-100 feet. Pterygophora californica Ruprecht Piel fig. 1: British Columbia to northern Baja California. Plants dark brown with a conspicuous midrib running through the main blade. Intertidal to 120 feet. Sargassum agardhianum Farlow Pl. 16, fig. 1. Southern California to central Baja California. Distinguished by its small size (about 2-3 feet tall), abundant branching and small “leaves” and sperical vesicles. Occasional, intertidal to 30 feet. Taonia lennebackerae J. Agardh Southern California to central Baja California. Yellowish-brown, tapering gradually from a wide apex to a rather pointed base, often much split and lacerated. Frequently found in sandy areas, intertidal to 30 feet. Zonaria farlowii Setchell and Gardner Pl, 4stie. I; PLS, fig. 1. Southern California to Bahia Magdalena, Baja California. The plants are dark brown with areas of light color near the terminal margins. Concentric hair lines are often visible. Mature specimens, 6-12 inches high, are much divided into small, terminal, fan-shaped segments. These show the characteristic “zones of growth” from which the plant derives its name. Intertidal to 50 feet.
Rep ALGAE Acrosorium uncinatum (Turner) Kylin PI. .34, fig. 1. Southern California to southern Baja California. Commonly epiphytic and entangled, bright rose red, with frequent hook-shaped branches. The veins are very delicate; intertidal to 125 feet. Agardhiella coulteri (Harvey) Setchell Pl. 29, fig. 3, -4. British Columbia to southern Baja California. A common and easily recognized, bright red, feathery plant of attractive appearance. Common and variable in size from 2 to 10 inches tall. Intertidal to 85 feet.
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S
very
PLATE 10 a mature and a young plant growing under natural conditions in
Macrocystis pyrifera, 30 feet of water.
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PLATE ies Fig. 1. Prerygophora californica, habit, showing midrib on terminal blade, x 0.25.
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a
f ? i | }
‘ a \ i
1 Pail) sto PEALE 12
Fig. 1-2. Pelagophycus porra: fig. 1. habit showing large single float and antler-like branching, x 0.04; fig. 2, juvenile plant showing development of float, x 0.25.
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PLATE 13 Fig. 1-3. Egregia laevigata: fig. 1, entire plant, x 0.04; fig. 2, portion of flat axis bear-
ing blades and floats, x 0.5; fig. 3, juvenile plant, showing undulate margins, x 0.25.
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PLATE 14 Cystoseira osmundacea, habit, showing rounded floats, x 0.37.
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44 Paciric NATURALIST Vou. 1, No. 14
Amphiroa dimorpha Lemoine P1723; figs 5: Central Baja California and southward. This is an exclusively deep- water plant of frequent occurrence at depths of 25-65 feet in the southern- most kelp areas. The small, pinkish branches are usually somewhat appressed to the substrate so that the flat segments have a dorsi-ventral aspect. : Amphiroa zonata Yendo . Bl. 23, sig. 6. Southern California to Tres Marias Islands, Mexico. The elongated and often branched calcareous segments of this small (1-2 inches) loosely-clumping, dichotomously branched plant are distinctive. Occasional at depths of 25 to 65 feet in our area. Amplisiphonia pacifica Hollenberg Pl. 43, fig. 2. British Columbia to central Baja California. A small, prostrate plant one to two inches in extent, consisting of overlapping lobes, provided with microscopic veins in a distinctive fan-like pattern. Occasional, on or around holdfasts of larger algae or in algal mixtures on rocks; intertidal to 60 feet. Anisocladella pacifica Kylin Pl. 38, fig. 2, 3. Central California to central Baja California. This small plant, about 1 inch high, often grows in mixtures of other small algae from the intertidal down to 40 feet. Binghamia forkii (Dawson) Silva Pl. 33, fig. 4. Southern California to southern Baja California. A very small, pink colored, slippery plant occasionally found at 25-40 feet growing congestedly with other small algae. Bossiella gardneri (Manza) Silva Pie 25, tig 7: Oregon to central Baja California. Similar to B. orbigniana but the segments are mostly rounded rather than with pointed wings. Frequent on the inner margins of the kelp beds and inshore into intertidal waters. Bossiella orbigniana (Decaisne) Silva PIn2h, fig. 5. Oregon to central Baja California. The fronds are 3-7 inches long, reddish-pink in color and dichotomously branched throughout. The usually sharply pointed wings of the flat segments are distinctive. Frequent from 25-55 feet. Botryoglossum farlowianum (J. Agardh) G. DeToni Pl. 40, fig. 1, 2. Washington to northern Baja California. This plant is rose-purplish, irridescent, to 10 inches high. Much larger than the somewhat similar Cryptopleura crispa and usually not epiphytic. Occasional, 20-45 feet. Botryocladia neushulii Dawson Pl. -32chig.. 2. Southern California to northern Baja California. This species differs from the following by its much smaller vesicles on the prominent solid branches. Botryocladia pseudodichotoma (Farlow) Kylin Sea Grapes PI. 33, fig. 3. British Columbia to southern Baja California. This plant has so
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PLATE 15
Fig. 1-2. Halidrys dioica: fig. 1, habit, x 0.37; fig. 2, a series of floats showing the flattened character, x 1.
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PLATE 16
Fig. 1. Sargassum agardhianum, upper portion of plant showing floats and blades, x 1.5. Fig. 2-3. Eisenia arborea: fig. 2, lower portion of plant showing holdfast, branching and teeth along blade margins, x_0.4; fig. 3, juvenile plant with proliferations along lower margins of the blade, x 0.4. Fig. 4. Smithora naiadum, growing on Phyllospadix, X 0.5. Fig. 5. Gloiophloea confusa, habit, x 0.75.
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PLATE 17 Fig. 1. Gelidium cartilagineum var. robustum, habit, X 0.75. Fig. 2. Gelidium pur- purascens, habit, X 1. Fig. 3, Peyssonelia rubra var. orientalis, a section through the crust-forming plant body showing rhizoids growing from basal cell layer and a spore group in a special (nemathecial) superficial l4yer, x 165. Fig. 4. Gloiophloea confusa, radial section through branch showing mixture of pigmented filaments and round color- less cells, X 30. (after Setchell)
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PLATE 18 #
xX 0.5. Fig. 2. Gelidium sp., cystocarp with two P., cystocarps, each with a single ostiole, x 16.
Fig. 1. Gelidium nudifrons, habit, ostioles, X 16. Fig. 3. Prerocladia 5
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PLATE 19 Fig. 1. Pterocladia pyramidale, upper portion of plant, x 2.5. Fig. 2-3. Leptocladia binghamiae: fig. 2, small upper portion of plant showing branching, x 2.7; fig. 3, tran- section of mature apex to show the single large central axial filament, x 46. Fig. 4-5. Melobesia mediocris: fig. 4, as found growing epiphytically on Phyllospadix, x 1; fig. 5, vertical section through tetrasporic conceptacle, x 430.
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es 50 Paciric NATURALIST VoL: 1, No. 14
distinctive a shape as to be confused with no others. Occasional at 40 to 85 feet. Branchioglossum undulatum Dawson Ply configs 2. Southern California to central Baja California. A very small species characteristically growing on kelp holdfasts with Myriogramme caespitosa. Calliarthron cheilosporioides Manza Pl222-Tig. 1. Northern British Columbia to southern Baja California. This is one of the most common bottom plants of the kelp community, and extends from the intertidal zones to a depth of 75 feet..The erect pinkish shoots sometimes reach a foot in height. Calliarthron regenerans Manza Pie-22, 87 2: British Columbia to central Baja California. This segmented, chalky- pink, calcareous plant forms erect clumps 3 to 7 inches tall on well-lighted bottoms to depths of 30 feet: It often occupies areas where there are abundant sea urchins. Callophyllis marginifructa Setchell and Sweezy Pa ties. Washington to northern Baja California. The blades are light, rosy red, 3-6 inches high when mature. The female plants are readily recognized by their conspicuous marginal reproductive bodies. Frequent, 10-65 feet. Callophyllis megalocar pa Setchell and Sweezy Pl. 28, fig. 3, 4. Washington to southern Baja California. Although the habit illustra- tions will serve in most cases, good fertile material may be required to distinguish some of these Callophyllis species. All are distinctly red in color, mostly between 3 and 8 inches high. These species has large cystocarps on the flat blades. Intertidal down to 45 feet. Callophyllis violacea J. Agardh Plo2iFfigid. Oregon to southern Baja California. This species is generally narrower than the other common Callophyllis species.and is often epiphytic on the lower parts of larger algae. Intertidal down to 75 feet. Carpopeltis bushiae (Farlow) Kylin PLizt. wig, 2. Southern California to southern Baja California. A common, small, erect, bushy plant, 4 to 5 inches high, with woody holdfast. It ranges from the lowermost intertidal to as much as 75 feet. Ceramium pacificum (Collins) Kylin Pi 37, est, 2. British Columbia to central Baja California; intertidal to 30 feet. A delicately branched dichotomous plant, often epiphytic, usually under 2 inches high. Chondria nidifica Harvey . Pl. 42, fig. 1. Southern California to southern Baja California. The cylindrical branches are 6 to 10 inches long, and bear distinctive tufts of short pointed lateral branchlets. Intertidal to 30 feet. Chondria californica (Collins) Kylin Pl. 42, fig. 4. Southern California southward. This is a bluish-irridescent small plant usually 2-3 inches tall. It oceurs in two forms, an erect, tufted form
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PLATE 20 Fig. 1. Agarum fimbriatum, holdfast and lower portion of blade showing midrib, holes and proliferations along stipe, x 0.38. Fig. 2. Lithothamnium giganteum, crustose habit showing rounded protuberances, x 1. Fig. 3. Lithothamnium lamellatum, crustose habit showing hitaiotice surface, X 1. Fig. 4. Lithophyllum imitans, crustose habit showing knobby protuberances, x 1.
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PLATE 21 Fig. 1. Dermatolithon dispar, growing epiphytically, x 1.5. Fig. 2-4. Corallina van- couveriensis: fig. 2, fertile branchlet, x 14; fig. 3, entire branch, x 1; fig. 4, upper part of branch, x 3. Fig. 5. Bossiella orbigniana, branch showing “‘arrow-head’” shaped segments, X 1.5.
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(81)
PLATE. 22 Fig. 1. Calliarthron cheilosporioides, habit, x 1. Fig. 2, Calliarthron regenerans, habit,
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PLATE 23 Fig. 1. Lithothrix aspergillum, upper portion of plant, xX 3.5. Fig. 2-3. Corallina gracilis: fig. 2, upper portion of plant, x 2.5; fig. 3, portion of axis showing antennae- bearing segments, X 5. Fig. 4. Corallina officinalis var. chilensis, upper portion of plant, Xx 1. Fig. 5. Amphiroa dimorpha, habit, X 1.125. Fig. 6, Amphiroa zonata, habit, x 1. Fig. 7. Bossiella gardneri, upper portion of plant showing rounded segments, x 1.5.
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PLATE 24
Fig. 1-2. Grateloupia schizophylla: fig. 1, habit, x 0.5; fig. 2, transection through a cystocarp, showing cortical cell rows. Fig. 3. Cryptonemia angustata, habit, x 0.5.
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56 Paciric NATURALIST Vou. il, No: 14
attached to rock or shell surfaces, and the more common epiphytic form (in the kelp community) with coiled, tendril-like branches. Intertidal to 30 feet. Corallina gracilis Lamouroux Phezomtie.2.. 3: Southern California to central Baja California. This species, and C. vancouveriensis are much more delicately branched plants than C. officinalis. C. gracilis is distinguished by the antehna-like branchlets on the swollen asexual reproductive segments. It is less prevalent and reaches lesser depths (to 30 feet) than C. officinalis. Corallina officinalis var. chilensis (Harvey) Kiitzing Plo niee. 4: Northern British Columbia to southern Baja California. This is one of the most common sea bottom plants found in the kelp community, extending from the intertidal zone to depths of 75 feet. The erect shoots often grow to six inches in height. Corallina vancouveriensis Yendo P22, ig. 2,4. Southern British Columbia to southern Baja California. This species is more representative of the intertidal zone than the deeper waters, but extends down to depths of about 30 feet. The branching is more compact than in C. gracilis. Cryptonemia angustata (Setchell and Gardner) Dawson Pi. 24, fig. 3. Southern California to southern Baja California. This thin, reddish, membranous plant grows occasionally on small stones and shells at depths of from 25 to 75 feet. It is thinner, narrower and more delicate than C. obovata. Cry ptonemia obovata J. Agardh BL Watig. 334. Alaska to central Baja California. This is a more amply expanded. membranous, red plant than the last, reaching a foot high, and with lobes to 3 inches broad. Occasional from 10 to 60 feet. Cryptopleura crispa Kylin PH 39; fig-2. Oregon to southern Baja California. Distinguished by its abundant small marginal lobes and usually smaller size than the next species. Commonly epiphytic; intertidal to 45 feet. Cry ptopleura violacea (J. Agardh) Kylin Pip Oe Tia 1s British Columbia to central Baja California. Unlike the former and the somewhat similar Botryoglossum farlowianum, this species bears asexual spores in longitudinal patches along the blade margins and sometimes also in scattered lobes. Intertidal to 30 feet. Dermatolithon dispar (Foslie) Foslie PAA tig. 1. Washington to central Baja California. This small, calcareous, epiphytic plant forms chalky pink crusts to 14 inch in diameter on flat surfaces of host plants, or may completely encase slender branches of such plants as Gelidium. At depths to about 30 feet. Drouetia peltata Dawson Pl iood, fio. 2 Southern California and northern Baja California. This is another of the exclusively deep-water plants of the shadowy bottoms under the
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4
PLATE 25
Fig. 1. Grateloupia howeii, habit, X 0.5. Fig. 2. Prionitis lanceolata, upper portion of plant, x 0.33. Fig. 3-4. Cryptonemia obovata: fig. 3, habit, x 0.5; fig. 4, cross-section of blade showing a characteristic medullary filament with highly refractive contents and
a single spore group.
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PLATE 26
Fig. 1. Prionitis cornea, habit showing sparse lateral branchlets, x 0.5. Fig. 2. Prion- itis andersoniana, habit, x 0.5.
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PLATE 27
Fig. 1. Callophyllis marginifructa, upper portion of cystocarpic plant, xX 1. Fig. 2. Carpopeltis bushiae, habit, xX 1. Fig. 3. Callophyllis violacea, upper portion of plant, yt RB
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60 Paciric NATURALIST Vou. 1, No. 14
kelp canopy and on out into depths of 100 feet or more. The blades show
a distinctive purplish iridescence.
Fauchea laciniata J. G. Agardh Pl. 32, fig. 4, 5. British Columbia to southern Baja California. A soft, pink-colored,
irregularly dissected slippery small plant, sometimes to 6 inches high, often
epiphytic on lower parts of larger algae in 30-75 feet.
Gastroclonium coulteri (Harvey) Kylin Pl. Jayphen), 2. British Columbia to central Baja California. A dull greenish species
readily recognized by its partitioned vesicular branchlets, but these are
sometimes so few or small in the southern part of the range that one must
be careful not to overlook them. Frequent, intertidal to 30 feet.
Gelidium cartilagineum var. robustum Gardner Plo Vitig-el: Southern British Columbia to Isla Magdalena, Baja California. This purplish-red plant often grows to two feet or more in height, and, thus, is a larger, coarser plant than G. purpurascens which is otherwise similar. In both of these species the young branchlets have a knee-like bend near their bases so that they are at first almost parallel to the branch bearing them. Common in rocky, well circulated areas from intertidal to 65 feet. Gelidium nudifrons Gardner Ph 16) figy 1. Southern California to central Baja California. Plants bright red to dark red, the much branched, almost cylindrical fronds of a tough, wiry texture. To 18 inches high, occasional, 10-75 feet. Gelidium purpurascens Gardner lg Mae Wes Cree Central California to northern Baja California. These dark, purplish- red colored plants are similar in structure and habit to G. cartilagineum, but are smaller (1 foot or less high) and more delicate throughout. Frequent, intertidal to 30 feet. - Gigartina binghamiae J. Agardh Pl. 30, fig. 1. Southern California to central Baja California. This is one of our broadest, bright-red colored algae and is characteristic of depths of 20-45 feet in colder areas. It is similar to the more northern G. corymbifera. Gigartina canaliculata Harvey Pl. 31y fig. 2: Oregon to Isla Magdalena, Baja California. This is characteristically a clumping, intertidal plant of dark, often greenish color with little red showing through. It extends only occasionally into the inner edges of the kelp community. Gigartina serrata Gardner Pl. 307sfig. 2.3" Southern California to southern Baja California. This plant suggests a large form of Gigartina canaliculata, reaching a foot or more in length. It is of a similar dark greenish color with a reddish cast. Occasional from the intertidal to 30 feet. Gigartina volans (C. A. Agardh) J. G. Agardh Pl..Shy fig. 3:
Oregon to central Baja California. A coarse, tough, dark, greenish-
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PLATE 28
Fig. 1-2. Gracilaria cunninghamii: fig. 1, habit, x 0.45; fig. 2, longitudinal section through frond, x 117. Fig. 3-4. Callophyllis megalocarpa: fig. 3, habit showing scat- tered cystocarps, X 0.5; fig. 4, cross-section through thallus, x 86.
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PLATE 29 Fig. 1. Phyllophora clevelandii, upper portion of plant, x 0.5. Fig. 2. Plocamium pacificum, small portion of branch, x 1. Fig. 3-4. Agardhiella coulteri: fig. 3, upper portion of plant, x 0.5; fig. 4, cross-section of inner medullary part of thallus, x 60.
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PLATE 30
Fig. 1. Gigartina binghamiae, habit, x 0.5. Fig. 2-3. Gigartina serrata: fig. 2, habit, x 0.5; fig. 3, branch tip of female plant showing pointed cystocarps, X 2.
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64 Paciric NATURALIST Vou. 1, No. 14
red plant characteristic of the lowermost intertidal but extending down to 30 feet.
Gloiphloea confusa Setchell Pl. 16, fig. 5; Pl. 17, fig. 4.
British Columbia to central Baja California. Plants are rose-red to deep red in color, 3 to 5 inches high, of a soft gelatinous texture. Occasional at 20-70 feet. One must examine the structure of the Tey in cross section to distinguish it from Scinaea.
Gracilaria cunninghamii Farlow | Pl 28 fig. 1, 2. Southern California to Isla Magdalena, Baja California. The irregu- lar dichotomous branching of this plant and lack of stolons at the base distinguish it from the several Rhodymenia species of similar structure and color. Frequent from intertidal to 45 feet. Grateloupia howeii Setchell and Gardner Pie25-figs 1. Central and southern Baja California. This species resembles a broad Gigartina because of the surface outgrowths, but may be distinguished in this flora by its dull, greenish-purple rather than red color, and more southerly range. Occasional from 10-45 feet. Grateloupia schizophylla Kitzing PL'24; figaly 2. Washington to southern Baja California. The long (1-2 feet), strap- shaped, simple or pinnately branched blades are of slippery texture. Occasional from intertidal to about 30 feet. The female reproductive structure, as illustrated, is distinctive. Griffithsia pacifica Kylin Pl. 36, fig. 3. British Columbia to southern Baja California. Plants forming densely branched, small pink clumps 2 to 4 inches high. The large cells of the filaments can be seen with the naked eye. Occasional, intertidal to 100 feet. Gymnogongrus leptophyllus J. G. Agardh Pl,32, fig. 1. Oregon to northern Baja California. This dull, brownish-red plant is distinguished by its small size, 3-5 inches, narrow, abundantly forked branches and dense, small-celled, internal structure. Frequent from intertidal to 30 feet. Laurencia diegoensis Dawson Pl. 43, fig. 1. Southern California to northern Baja California. Usually dul! greenish-red in color, to 10 inches high, growing on rocks from the intertidal to 30 feet. Laurencia splendens Hollenberg Pl. 43, fig. 4. Central California to northern Baja California. Epiphytic and usually only 2 to 4 inches high in our area. Intertidal to 30 feet. Laurencia subopposita (J. Agardh) Setchell Pi '43, fig. 3. Southern California to central Baja California. The coiled, tendril- like, blunt branches which occur on this bright red, epiphytic plant are distinctive. Occasional, 10-50 feet. Leptocladia binghamiae J. Agardh PLO. tigre 2 as. Central California to Isla Magdalena,.Baja California. Deep red in
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PLATE 31
‘tornica, habit x 0.5. Fi
8. 2. Gigartina canaliculata, habit, x 1.
Fig. 1. Phyllophora cali Fig. 3. Gigartina volans,
habit, x 0.5.
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PLATE 32
Fig. 1. Gymnogongrus leptophyllus, habit, x 1. Fig. 2. Botryocladia neushulii, habit, x 0.5. Fig. 4-5. Fauchea laciniata: fig. 4, upper portion of female plant, showing cysto- carps, X 1; fig. 5, crown-shaped cystocarps, X 15.
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PLATE 33 Fig. 1. Sciadophycus stellatus, habit of plant lacking holdfast, x 2. Fig. 2. Branchio- glossum undulatum, a blade bearing flaired cystocarps, xX 7.5. Fig. 3. Botryocladia pseudodichotoma, upper portion of plant, x 0.5. Fig. 4. Binghamia forkii, upper por- tion of plant, x 3. Fig. 5, Myriogramme caespitosa, habit, x 8.
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68 Paciric NATURALIST Vou. 1, No. 14
color, to 1 foot high. The markedly flattened branches and irregular marginal teeth distinguish it externally, but a cross section to show the distinctive structure may sometimes be necessary for confirmation. Occa- sional, 10-65 feet. Lithophyllum imitans Foslie . Pl. 20, fig. 4. Central California to central Baja California, The thallus forms a pink colored, coarse, somewhat glossy, hard crust on the surface of rocks or shells in depths of 10-75 feet. The small diameter of the protuberances is distinctive. ; Lithothamnium giganteum L. R. Mason PI. 20, fig. 2. Southern California to central Baja California. This is the coarsest of our nodular species of Lithothamnium. The protuberances are large and have somewhat swollen tips. The pinkish-purple thallus often completely encloses a small stone and lies free on the bottom in depths of 20-60 feet. From a similar species of Lithophyllum (L. grumosum) it is distinguished microscopically by the presence of many small pores (rather than a single pore) in the cap of the non-sexual reproductive cavities. Lithothamnium lamellatum Setchell and Foslie Pl 20, figs 3: Central California to central Baja California. The smooth-surfaced. pinkish, shingle-like thallus of lobes about 14 inch in diameter forms loosely attached crusts on rocks and the basal portions of larger algae at depths of 20-75 feet. The crusts are distinctly calcareous, brittle and over- lapping, unlike Peyssonelia. Lithothrix aspergillum J. E. Gray Pi23, tigi. Southern British Columbia to southern Baja California. The nearly cylindrical thallus and very short segments are distinctive of this bushy little calcareous plant, 4-5 inches high, which is frequent from the intertidal to depths of 40 feet. Melobesia mediocris (Foslie) Setchell and Mason Plo stig. 4; 5. Northern British Columbia to Isla Magdalena, Baja California. This is another epiphyte found exclusively on Phyllospadix. The plants are often extremely abundant, forming small, pink crusts on the surfaces of the slender green leaves. Microcladia coulteri Harvey Pl. 37, fig. 3, 4. British Columbia to central Baja California. This is a feathery, delicate species 2 to 8 inches high suggesting Plocamium but of a darker color. It grows epiphytically on various larger algae from intertidal to 30 feet. Myriogramme caespitosa Dawson Pl. 33, fig. 5. Southern California to southern Baja California. A very small clumping species characteristically growing on kelp holdfasts. Nienburgia andersoniana (J. Agardh) Kylin P1138) fig... Oregon to southern Baja California, intertidal to 80 feet. This plant varies greatly in size (3-10 inches), branching and breadth of blade, but
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PLATE 34 Fig. 1. Acrosorium uncinatum, habit showing hooked tips, X 1.5. Fig. 2. Droxetia rotata, habit showing growth scars on stipe, x 0.5. Fig. 3. Rhodymenia palmettiformis, habit showing horizontal stolons, x 0.5. Fig. 4. Rhodymenia pacifica, longitudinal section through thallus, x 107. Fig. 5. Rhodymenia arborescens, habit, x 0.5.
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PLATE 35 Fig. 1-2. Gastroclonium coulteri: fig. 1, habit showing many-chambered laterals, x 0.75; fig. 2, lateral branchlet showing diaphrams, x 2. Fig. 3. Rhodymenia californica, habit showing basal rhizoids, x 0.75. Rhodymenia attenuata, habit showing basal rhizoids,
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1
PLATE 36
Fig. 1-2. Spermothamnion snyderae: fig. 1, sterile branch, X 8; fig. 2, branch with polysporangia, X 160. Fig. 3. Griffithsia pacifica, small upper part of male plant, x 8 Fig. 4. Rhodymenia pacifica, habit showing basal stolons, x 0.75.
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ed Paciric NATURALIST VoL. 1, No. 14
is recognized by its venation and marginal teeth. It often exhibits patches of bluish iridescence. Peyssonelia rubra var. orientalis Weber van Bosse PhAAT; figh 3. Throughout Pacific Mexico. This is a small, bright red, crust-like plant frequently found closely affixed except at the margins to rocks in shaded intertidal areas to about 60 feet. It is the commonest of several similar species which can be distinguished only by vertical sections through reproductive parts. Phyllophora californica (J. Agardh) Kylin Pico heir. Central California to northern Baja California. The repeated regenera- tion of flat blades from cylindrical stipes is distinctive of this characteris- tically sublittoral plant of dull, dark reddish color, which reaches 4-6 inches in height. Occasional at 10-50 feet.
Phyllophora clevelandii Farlow Bly 29h: 1. Southern California to northern Baja California. This is a characteris- tically deep water, rose-red colored plant found under the kelp canopy at depths of 50 feet and on out to dimly lighted bottoms at 100 feet or more. None of the other species inhabiting these depths have the distinctively broad branch tips. Pogonophorella californica (J. Agardh) Silva PI. 39, fig. 3, 4. Southern California to central Baja California. This is one of the small species found in mixtures on rocks or around the bases of larger plants. The small tufts of hairs on the upper parts of the erect, cylindrical branches are distinctive. Intertidal to 60 feet. Plocamium pacificum Kylin Pl. 29g. 2; A common and easily recognized, bright red, feathery plant of attractive appearance. Common and variable in size from 2 to 10 inches tall, intertidal to 85 feet. Polyneura latissima (Harvey) Kylin Pl. 38, fig. 4. Northern British Columbia to southern Baja California, intertidal to 60 feet. The anastomosing vein pattern of this rose-red colored species sets it apart from others in our area. Polysiphonia johnstonii Setchell and Gardner PlZAls fig: 3,6: Central and southern Baja California. This is probably the most frequent sublittoral species of this genus in which 5 or 6 cells occur per tier. It will be encountered as an epiphyte to depths of about 30 feet. Polysiphonia mollis Harvey Pl. 41, fig. 7, 8. Washington to central Mexico. This is the commonest of the several species of this genus having 4 cells per tier. It will be encountered as a slender filamentous epiphyte at depths to 50 feet. Prionitis andersoniana (Eaton) Dawson Pl 26.0185 2. Oregon to central Baja California. Occasional to 30 feet. The thallus is deep rose-red and is of a smooth, firm, tough texture. The plants may reach a foot or more in length.
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PLATE 37
Fig. 1-2. Ceramium pacificum: fig. 1, large portion of plant, x 0.5; fig. 2, small part of a branch to show the irregular arrangement of the cortical cells over the large sub- spherical cells of the axial filament, x 238. Fig. 3-4. Microcladia coulteri: fig. 3, upper portion of branch, x 1.5; fig. 4, branchlet with cystocarps, x 5.
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; PLATE 38 Fig. 1. Nienburgia andersoniana, upper portion of branch, x 1. Fig. 2-3. Anisocladella
pacifica: fig. 2, sterile plant, x 2; fig
. 3, fertile blade of tetrasporic plant, x 2. Fig. 4, Polyneura latissima, habit, X 0.75,
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PLATE 39 Fig. 1. Cryptopleura violacea, showing lateral tetrasporangia, X 0.5. Fig. 2. Crypto- pleura crispa, showing tetrasporangia on small lateral lobes, x 0.5. Fig. 3-4. Pogono- phorella californica: fig. 3, habit showing scattered tufts of hairs near tips of branches, Xx 1.5; fig. 4, tuft of hairs with spermatangial clumps, x 50.
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76 Paciric NATURALIST Vou. 1, No. 14
Prionitis cornea (Okamura) Dawson PEI26,-figs 2;
Southern California to central Baja California. The flattened, dicho- tomous, cartilaginous, deep red fronds, 6-7 inches high, with irregular or scant, very short secondary branchlets, are distinctive. Occasional at 25 to 65 feet, and extending into the lowest intertidal zone.
Prionitis lanceolata Harvey Phe), fie, <2.
British Columbia to northern Baja California. These plants reach 2 feet in height, are dark, dull reddish-purple in color. The texture is firm and coarse. Frequent from 40 feet up into the intertidal.
Pterochondria pygmaea (Setchell) Hollenberg Pl: 42, fig. 3.
Southern California to -central Baja California. Similar to the next species but smaller and proportionally broader. Almost always found as an epiphyte on the upper parts of Cystoseira.
Pterochondria woodii (Harvey) Hollenberg Pia Eerie: sl, <2.
British Columbia to central Baja California. Similar to the former but larger and proportionally narrower. Epiphytic on the upper parts of Cystoseira.
Pterocladia pyramidale (Gardner) Dawson PLAS, tig. S23 PE 19, hel.
Southern California to Isla Magdalena, Baja California. This plant is often confused with the flattened Gelidiwm species, but is macroscopically distinguishable in most cases by its branchlets which extend perpendicu- larly from the major branches rather than having a knee-like bend toward the major branch apex. The single-pored female reproductive bodies (cystocarps) are distinctive, but these are infrequently found. Mature plants may reach nearly 1 foot in height and often have the upper branches
reduced and somewhat matted. Common from the intertidal zone down to 45 feet.
Pterosiphonia baileyi (Harvey) Falkenberg Pl. 42, fig. 2.
Northern California to central Baja California. A dark colored, almost black, small, delicately branched plant to 6 inches met usually on rocks, intertidal to 30 feet.
Pterosiphonia dendroidea (Montagne) Falkenberg Pl. 41, fig. 3, 4. British Columbia to southern Baja California. A very common small species 1 to 2 inches high. It grows with other small forms on rocks, shells and holdfasts of larger algae from the intertidal to 50 feet. It is usually very dark dull reddish in color and resembles a minute feather.
Rhodymenia arborescens Dawson Pi. 34; fig. 5.
Southern California to Southern Baja California. This plant is dull red, 5 to 7 inches high. It is one of the common species of the shaded areas under the kelp canopy and on out to depths of 115 feet. The woody conical holdfast is distinctive for this genus. Note that the base may often be covered by animal material.
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PLATE 40
Fig. 1-2. Botryoglossum farlowianum: fig. 1, entire plant, x 0.5; fig. 2, segment of blade, x 1.
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PLATE 41
Fig. 1-2. Pterochondria woodii: fig. 1, upper portion of plant, x 0.75; fig. 2, apex of a branch, x 13. Fig. 3-4, Pterostphonia dendriodea: fig. 3, erect axis showing branch- ing, X 3.5; fig. 4, detail of branch tip, X 35.*Fig. 5-6, Polysiphonia johnstonii: fig. 5, branch tip, x 143; fig. 6, portion of axis showing arrangement of cortical cells. 98. Fig. 7-8. Polysiphonia mollis: fig. 7, portion of branch, x 15; fig. 8, branch tip, x 325. (Fig. 7 after Hollenberg)
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My - LY
PLATE 42
Fig. 1. Chondria nidifica, habit showing tufts on branches, x 1. Fig. 2, Prerosiphonia baileyi, habit, x 0.75. Fig. 3. Pterochondria pygmaea, cell structure of branch tip, x 15. Fig. 4. Chondria californica, entire plant growing epiphytically, x 1.
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80 Paciric NATURALIST Vor. 1, No. 14
Rhodymenia attenuata Dawson Ph Soe L1G, Fae Central California to central Baja California. The attenuate or spatulate blades of this small red plant (2-3 inches high) distinguish it from the several other stolon-bearing Rhodymenia species. Occasional, 35-65 feet. ‘ Rhodymenia californica Kylin PI. 353 fig. 3. British Columbia to southern Baja California. Plants bright red, sometimes with white blotches, 1:3 inches high. It is the smallest and narrowest species of this genus. Frequent from intertidal to 69 feet. Rhodymenia pacifica Kylin Pl. 34, fig. 4; Pl. 36, fig. 4. British Columbia to northern Baja California, 10-50 feet. This and the next species must be distinguished by the characters given in the key and by the illustrations. Rhodymenia palmettiformis Dawson Pl. 34, fig. 3. Southern California to northern Baja California, intertidal to 40 feet. Distinguished by key and illustrations. Sciadophycus stellatus Dawson Pl. 33,12. 1. Southern California to central Baja California. This distinctive species is characteristic of deeply shaded bottoms under the kelp canopy or out into deeper water to as much as 150 feet. Scinaea johnstoniae Setchell Bieri fe. 05. Southern California to Islas Tres Marias, Mexico. Macroscopically identical with Gloiophloea. The two genera are distinguished by the struc- ture of the cortex as shown in Plate 17. Occasional in our area at depths of 20-60 feet. Smithora naiadum (Anderson) Hollenberg Pl. 16, fig. 4. Northern British Columbia to Isla Magdalena, Baja California. This is the only small (under 1 inch), membranous red alga to be found growing exclusively on Phyllospadix in our area. It is of seasonal occur- rence from intertidal to 30 foot depths. Stenogramme interrupta (C. Agardh) Montagne BE 32, figs 3. British Columbia to southern Baja California. This plant has a great depth range from just below the intertidal to 135 feet. It is rose red in color, and both morphologically and structurally like Rhodymenia and Gracilaria, but fertile plants are readily recognized; the female ones, by the broken medial lines, and asexual ones by their blotched spore-bearing areas. Spermothamnion snyderae Farlow P1;06, figh1, 2: Central California to central Baja California. Intertidal to 50 feet. This plant forms patches of soft red hair 1-2 inches long, often mixed with other small algae.
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PLATE 43 Fig. 1. Laurencia diegoensis, habit, X 0.66. Fig. 2. Amplisiphonia pacifica, upper por- tion of plant, xX 1.5. Fig. 3. Laurencia supopposita, plant growing entwined around host, X 1. Fig. 4. Laurencia splendens, habit, x 1.
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Cosmic-Ray-Produced
Silicon-32 in Nature
Silicon-32, discovered in marine sponges, shows promise as a means for dating oceanographic phenomena.
Devendra Lal, Edward D. Goldberg, Minoru Koide
The nuclear transmutations resulting from the interaction of cosmic rays with nuclear species in the atmosphere have produced a variety of radioactive prod- ucts detectable on the surface of the earth. Such isotopes as C'', H’, Be’’, and P* have been found, and their individual distributions and concentrations in the various geological domains have led to many significant concepts and contribu- tions in geochemistry, geophysics, and geochronology (see, for example, /).
This article (2) concerns still another
isotope produced by cosmic rays—Si™, which we have detected in the marine environment. It is thought that this isotope is produced from the nuclear spallations of argon by cosmic rays. It has a half-life of roughly 710 years (3). Any Si* that reaches the earth from the atmosphere will be rapidly diluted with stable silicon, and the resulting specific activity of Si* will be very small. How- ever, Si* decays by negatron (8°) emis- sion to P™, which is a negatron emitter with a half-life of 14.3 days. This makes
‘ontributions from the Scripps Institution of Oceanography, New Series, 11/3 a
Reproduced by Permission
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it possible to detect Si* by milking and by counting the P* daughter from large amounts of silicon.
The principal exchange reservoir for Si* is probably the marine hydrosphere which most likely receives Si* via oceanic rains. The small amounts of silicon in surface marine waters should yield a relatively high specific activity of Si*, whereas the fallout on land will be so diluted by exchange and other chemical interactions with the exposed crustal materials that the detection of this nuclide will be extremely difficult. We estimate the average concentration of Si* to be 2.6 x 10° disintegrations per minute, per liter of sea water, or 8 disintegrations per minute, per kilogram of silicon, for a hypothetical thoroughly mixed ocean. The amount of sea water required to yield 1 disintegration per minute, an activity conveniently detect- able, is 3.8 X 10* liters. Since the han- dling of such an amount of water for the extraction of silicon presents many difficulties, Si* was sought initially in siliceous (opaline) sponges, which derive
The authors are affiliated with the Scripps In- stitution of Oceanography, University of Cali- fornia, La Jolla. Dr. Lal is on leave from the Tata Institute of Fundamental Research, Bombay, India.
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their silicon from sea water and are available in abundance, especially on the sea floors of the continental shelf. Three sponges trawled from the Gulf of Cali- fornia in 1956 were analyzed.
The experimental techniques and the results are presented in the next section. In the third section, an estimate of the rate of production of Si* in the atmos- phere from the available cosmic ray and accelerator data is presented. The ap- plications of Si* as a tracer for studyin geochemical and geophysical processes with special reference to oceanography are discussed in the last section.
Experimental Techniques and Results
Chemical procedure. The sponges were first cleansed of organic matter and foreign materials, not incorporated in the opaline structure, by digestion with nitric acid, followed by repeated washings with water and acetone. Ap- proximately 200 grams of this material was allowed to stand for 3 months to allow the P* to build up.
The milking procedure was initiated by treating the sample (after grinding) with a 50 percent solution of sodium hydroxide containing a known amount of carrier phosphate, in a polypropylene beaker. The solution was heated to speed up the dissolution. Hydrogen peroxide was added fo remove any in- terstitial organic matter which was re- leased during the breakdown of the opal. At this point approximately 95 percent of the silicon was in solution; the remaining 5 percent was treated with hydrogen fluoride and sulfuric acid, and heated to near-dryness; finally the resi- due was dissolved in HNOs.
The dissolved silicon in the NaOH solution was dehydrated to the SiO: form by the addition of 400 ml of con- centrated hydrochloric acid and filtra- tion through a Biichner funnel. The silica was dried at 130°C and washed thoroughly with dilute HCl to remove any adsorbed phosphorus compounds. The filtrate, washings, and the solution resulting from the treatment with HF and H:SO. were combined and evapo- rated until the sodium chloride had crystallized out. The salt was removed by filtration through a sintered glass funnel and washed with concentrated HCl. These evaporation steps were re- peated twice to remove the bulk of the NaCl. The final filtrate was taken to dry- ness, digested with 6N HCl, and dehy- drated. This step was repeated twice to
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render insoluble any remaining traces of silica. The residue was heated with perchloric acid to dryness, and dissolu- tion was effected in 20 ml of concen- trated HNOs.
The phosphorus was extracted from the above solution and purified by the following steps carried out in accord- ance with often published standard procedures (4): (i) phosphoammonium molybdate precipitation; (ii) magnesium ammonium phosphate precipitation; (iii) elimination of cations by passage through a Dowex-50 cation exchange resin in the H-form; (iv) magnesium ammonium phosphate precipitation; and (v) ignition to magnesium pyrophos- phate. This solid was assayed for its radioactivity.
After an initial counting, the sample was subjected to additional chemical purification by a repetition of the last four steps. The silica recovered in the dehydration step was milked again after a period of 28 days.
Counting techniques. The samples were deposited over an area of approxi- mately 6 cm* on two split cylindrical copper supports and counted in a cy- lindrical geometry with a_ thin-wall, flow-type Geiger tube with “Q gas” (98.7 percent He; 1.3 percent isobu- tane). The details of the counter have
been described by Martell (5). The counter was housed in a shield which provided a minimum of 8 inches of steel on all sides and was operated in anticoincidence with a ring of large cosmic ray counters to eliminate the recording of cosmic ray »-mesons. The background counting rate with blank copper supports was 0.26 count per minute. The counting efficiency for hard beta rays was determined by assaying a weighed sample of potassium chloride for K” f-radiation (Emax. = 1.34 Mev) under conditions similar to those em- ployed for our samples. The over-all counting efficiency, which includes the counting geometry, back-scattering from the support, and absorption in the counter wall, was found to be 37 per- cent.
Several blank runs were made to as- certain the amount of contamination arising from chemical reagents and dust in the laboratory. The net counting rates of the blanks varied between 0 + 0.05 and 0.05 + 0.04 count per minute. A small, but positive, blank of 0.025 count per minute resulting from man-made or natural activities is in- dicated.
Results. The chemical yields of phos- phorus and the activities of Si* are sum- marized in Tables 1 and 2, respectively.
Table 1. Chemical yields.
Dry Amount of Z re Remarks sample weight carrier added one e (gm SiOz) (mg Mg2P207 eq.) 1 First milking 200 120 92 IR First milking recycle 83 2 Second milking 190* 135 66
*Five percent of sample 1 did not dissolve in NaOH treatment. It was treated with HF and H2SO., and therefore was not available for the second milking.
Table 2. Counting data.
time elansed Estimated No. of Period of Net sample between end. disintegrations of king counting rate of milking Si? per minute, per om (count/min) and counting kilogram of Si * (day) Sample No. I 3 mo 0.52 + 0.07 2 20.0 + 2.7 Sample No, IR 0.36 + 0.04 4 0.41 + 0.05 7 0.28 + 0.04 13 19.9 + 1.7 0.21 + 0.04 20 0.11 + 0.03 28 Sample No. 2 28 days 0.26 + 0.04 2 18.9 + 2.9
Mean 19.6 + 1.3
* Self-absorption in the sample was assumed to be 6 percent in all cases.
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The observed activity of the samples can be unambiguously attributed to the presence of P® on the basis of the fol- lowing four independent checks on the nature of the radiation:
1) Half-life. The activity: of sample 1R was followed for a period of two half-lives of P*. The counting data are assembled in Table 2. The observed half-life of the activity, 13 + 4 days, is in good agreement with the literature value for P*, 14.3 days.
2) Chemical behavior. Sample 1 was recycled through the purification steps 1 to 4 with the result that the specific activity of the recycled sample remained unchanged within the errors of measure- ment (Tables 1 and 2).
3) Beta energy. Absorption measure- ments of sample 1, with vinyl acetate absorbers of thicknesses 51 and 102 mg/cm’, yield a half-thickness value of
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75 + 20 mg/cm’. The P® half-thickness for cylindrical counting geometry had previously been found to be 84.3 mg/cm’ of aluminum (6). The vinyl acetate half-thickness, in milligrams per square centimeter, is expected to be about 13 percent higher than that for aluminum absorbers. The thinness of the samples, coupled with appreciable back- scattered radiation, on the other hand, should yield a slightly smaller half-thick- ness. In view of this, the energy of the beta radiation is consistent with that of. p® (7).
4) Growth of daughter activity. The estimated disintegration rates of »Si® from the first and second milking are concordant.
These results prove conclusively that the observed activity is due to P® and that it arises from the decay of the parent nuclide Si®.
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100 MONOMERIC SILICIC ACID IN MICROMOLES/LITER
150
Fig. 1. Vertical distribution of silicic acid in the Atlantic and Pacific oceans. Broken curve: North Atlantic Ocean, latitude 47°24’N, longitude 07°52’W [data from Arm- strong (/8)}. Solid curve: North Pacific Ocean, latitude 26°22.4'N, longitude 168°57.5'W
[Goldberg (/9)].
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Rate of Production of Silicon-32
The production rate of Si” can be calculated from the available cosmic ray data, in different regions of the a4tmos- phere, on (i) the star production rates in photographic emulsions and cloud chambers; (ii) the frequency distribution of stars as a function of the number of charged particles emitted; and (iii) the observed variation in the intensity of slow and fast neutrons. Lal et al. (8) have calculated the production rates of Pp”, P*, and S* in spallations of atmos- pheric argon for all regions of the atmosphere from such data. By their procedure, the global production rate of Si* is computed to be 1.7 x 10° atom/cm? column per second.
A second estimate can be made by using the observed fallout of cosmic- ray-produced P* and the expected ratio of cross sections for the production of Si* and P*” from argon at energies of interest in cosmic rays. The fallout of P* was measured at tropical latitudes during the years 1956-58 (9) to be 3.4 x 10° atoms of P*/cm’ per year. This value is shown to be predominant- ly due to the removal by wet precipita- tions of activity produced in the tropo- sphere only, with a mean removal period of 40 days. By correcting this figure for the decay of P®* in the tropo- sphere and taking a value of 29 percent for the fraction of P* produced below the tropopause (8), a production rate for P* of 1.1 X 10° atom/cm* per second is obtained. The ratio of the cross sec-. tions of Si* and P* is computed to be 0.2 from Rudstam’s empirical relation (10) describing the cross sections for the formation of nuclides in nuclear spallations.
The ratio of formation cross sections for two isobars, (A4,Z) and (A,Z’). de- pends on two parameters only:
a (A,Z)/o (A,Z’)
= exp'\— RUZ — SA)* — (2 SA)
= exp [R(Z’ — Z) (Z’ + Z — 2SA)] The values of the parameters R and S are found to be nearly insensitive to either the bombarding energy or the target nucleus for masses between 51 and 75. In order to approximate our situation, we have used the values observed in the bombardments of vanadium by 60-, 100-, 170-, 175-, and 240-Mev protons: R = 16 + 0.1; S = 0.468 + 0.001. Therefore the ratio of cross sections is
a (Si*) /o (P*) = exp [R(Z 4+ Z’ — 2SA)} = 0,2" 0:02
The production rate of Si* therefore
amounts to 0.2 x 1.1 X 10° = 2.2 x 10“ atom/cm’ per second, which is in good agreement with the previous es- timate (1.7 x 10“).
We take 2.0 x 10“ atoms/cm* per second as the average global production rate of Si* in the atmosphere. The cor- responding inventory of Si* on the earth is 28 kilocuries, or 1.75 kg of Si®.
The production of Si* in any sig- nificant quantities by nuclear weapons
seems quite improbable but cannot be’
entirely ruled out at present. It cannot result from surface shots by principal neutron capture reactions, (m, y), (n, p)