PHYTOPLANKTON OF SOUTH GEORGIA 



59 



were also found in the old Bellingshausen Sea water to the north-west, and at a few of 

 the stations worked in the older water derived from the eastern Weddell Sea. 



On this survey Thalassiothrix antarctica was widely distributed in all three types of 

 surface water, but again showed a maximum to the south in the western Weddell Sea 

 water (Fig. 28). The seasonal distribution of this species presents some very interesting 

 features, which admit only hypothetical explanation until further data are available. 



Fig. 28. The distribution of Thalassiothrix antarctica, South Georgia survey, November 1930. i = one 



million. 



On the present survey (late spring) it totalled some 77I millions, on the survey described 

 by Hardy (midsummer) only half a million, but on the January-February (late summer) 

 survey of 1929-30 nearly 20 millions. This gives the appearance of a species with a big 

 spring and comparatively small autumnal maximum, such as is found among many of 

 the better known forms in north temperate latitudes ; but it may very well be that this 

 unequal distribution is due, at least in part, to variation in the extent and intensity of 

 the surface currents, as this same species was found abundantly to the west of the 



Bellingshausen Sea at mid-season 1930-1 but was by no means so plentiful in that 



8-2 



