PHYTOPLANKTON OF SOUTH GEORGIA 



63 



from which it will be seen that besides Thalassiosira, three of the less numerous forms, 

 Corethron valdiviae, Fragilaria antarctica and Rhizosolenia data, reached their maximum 

 at the surface, while other forms even more rare at this particular station attained their 

 highest numbers at depths of 5 and 10 m. 



Table 12 



OTHER MATERIAL 



One piece of work in the South Georgia area during the 1930-1 season remains to be 

 discussed, namely a repetition of the Prince Olaf line, worked by the R.R.S. 'William 

 Scoresby' in March. As will be seen from Table XVI, in which the full analyses of the 

 material then collected are given, these stations were worked in two periods, with a 

 considerable interval between. This was caused by very bad weather, sufficiently severe 

 to cause damage to shipping in the locality. 



The stations worked during the first week of March 193 1 comprised the three inshore 

 stations on this line, and the outermost. At St. WS 567 close in to the land, the phyto- 

 plankton was almost non-existent, Corethron valdiviae being dominant in a very poor 

 catch. This was explicable on the grounds of inshore influences, as was clearly shown by 

 the presence of a small Tintinnid, which has been found to be very characteristic of in- 

 shore waters at South Georgia and in the Bransfield Strait. At the two succeeding stations 

 moderate hauls were obtained, in which C. valdiviae and Chaetoceros criophilum 

 were dominant. At the outermost station on the line, the estimated diatom total was over 

 12 millions, Ch. criophilum and Nitzschia seriata being strongly dominant, with 

 lesser numbers oi Dactyliosolen antarctictis, Chaetoceros neglectus and Corethron. Turning 

 now to the stations worked towards the end of the month (Sts. WS 572-5 inclusive) 

 we find Nitzschia seriata and Chaetoceros criophilum dominant in moderately rich 

 hauls, with lesser numbers of Ch. atlanticus, Corethron, Chaetoceros neglectus and 

 Dactyliosolen antarctictis, in that order of importance, at the three outermost stations. 

 At St. WS 572 Chaetoceros criophilum formed roughly two-thirds, and Corethron 

 valdiviae one-third of a sample in which only two other diatom species were observed. 



