Distribution of surface phytoplankton between New Zealand and Antarctica, December 1957

During the Trans-Antarctic Expedition 1955-1958, the distribution of phytoplankton in the southern ocean and Ross Sea was investigated from fifty-seven samples taken at roughly 30-mile intervals between southern New Zealand and McMurdo Sound. The greatest diversity of species occurred between 55° and 60°S, just north of the Antarctic Convergence. Maximum concentration was found at 70° to 72°S, where Corethron crioplhilum was profoundly dominant. A predominately sub-Antarctic assemblage between 52° and 64°S was dominated by nine species not found in significant quantities elsewhere in the series of samples. Only two of these extended in appreciable numbers into the Ross Sea. Six of the commonest species ranged from sub-Antarctic waters southwards across the Antarctic Convergence, and two were not recorded north of the Ross Sea.