Antarctic Record (Mar 1986)
Seasonal changes of chlorophyll α standing stocks and oceanographic conditions under fast ice near Syowa Station, Antarctica, in 1983/84
Abstract
Phytoplankton pigments and oceanographic parameters were measured in water column under the fast ice near Syowa Station (69°00'S, 39°35'E) from February 1983 to January 1984. Water temperature and practical salinity ranged from -0.94 to -2.11℃ and from 32.42 to 34.70,respectively. After the flowout of sea ice in May 1983,very unusual event in recent years, the water column was mixed vertically in June, and then supercooled surface water beneath the newly formed ice appeared in late July, which differed remarkably from the phenomena in the preceding year. In this study, maximum chlorophyll α concentration of 4.99mg/m^3 was recorded in middle February 1983,and it descreased in middle March. The winter minimum less than 0.1mg chl.α/m^3 was observed from June to October, and the concentration increased again after early December. The standing stocks of chlorophyll α in middle January of the present year (1984) were less than half of those in the preceding year (1983). This could be explained by smaller light penetration into the underlying water between spring and summer of 1983/84 probably due to thicker snow cover on the sea ice comparing to that in 1982/83.