Changes in phytoplankton as indicated by spectrophotometric chlorophyll estimations 1952-53 63 



need not be assumed to be the same as at 50 m, which was done in the 1953 paper. 

 Fig. 1 illustrates the autumn growth from August 1952 (linking up with Atkins and 

 Jenkins, 1953, Fig. 7) to October, with a surface outburst in September. Growth 

 fell to a value almost uniform with depth during November and December in an 

 almost isothermal water column. 



Table III — Algae identified in enriched cultures exposed to light 



Signs : — not found 



A present 



B more frequent 



C plentiful 



D very plentiful 



O not found in one of the two cruises 



Where two letters occur 

 for one month, two 

 cruises were under- 

 taken 



Chlorophyceae 



Years 



F M A M J 



O N 



D 



Chlamydo- 



monadaceae 

 Chlamydomonas sp. 



POLYBLEPHARIDACEAE 



Pyramimonas sp. 



Chlorellaceae 

 Chlorella sp. 



Ulotrichaceae 

 Stichococciis sp. 



Ulothrix subflaccida 



Chaetophoraceae 

 Ectochaete sp. 



Chrysophyceae 

 Chrysomonad sp. 



Coccolithophora sp. 



ISOCHRYSIDACEAE 



Dicrateria sp. 

 OCHROMONADACEAE 



Ochromonas sp. 



Chrysoca psaceae 

 Phaeocystis globosa 



Cyanophyceae 



Oscillatoriaceae 

 Oscillatoria sp. 



Cryptophyceae 

 Cryptomonad sp. 



Cryptomonas sp. 



Hemiselmis rufescens 



1952 

 1953 



1952 

 1953 



1952 

 1953 



1952 

 1953 

 1952 

 1953 



1952 

 1953 



1952 

 1953 

 1952 

 1953 



— — B — 

 C C BB OA 



D 



B 



D 



1953 

 1953 

 1953 i A 



1953 



1952 

 1953 

 1952 

 1953 I B 



1952 ! D 



1953 — 



DA 



C 

 B 



D D 

 — A 



A 



C — B— — — — — — B 



A — OC— — A _____ 



_DDDCBAADCD 

 BBB— ADB— — — — — — 



— C DC C B— — — — — 



— OB OA — DO — — — — D — 

 A _____ — — — — — 

 AAOAO— — — — — — — — 



— C D A C — — B A A A 



— AO— — OC— — — — — — 



_____B ___ — — 



C---------B 



D D D D D D 

 D CD DC D DD B D D DD D D 



__OC — BC — — — — — — 



A — — — — — — — — — — 



AOCDBD — — — — — — — 



_— OA— — — — — — — — 



___--B----B 



_ _ BA - - -• - - 1^^ ^ A 



£3ZZZZZ — — D D 



_ OC - _ — B OD — 



