Surface distribution of chlorophyllα along the course of the FUJI(1980-81)in the Southern Ocean

Abstract

The measurement of the chlorophyll α concentration of the surface water in the Southern Ocean was performed along the course of the icebreaker FUJI from December 1980 to March 1981 as a part of the 22nd Japanese Antarctic Research Expedition. The chlorophyll α concentration was low (less than 0.2mg/m^3) in the Subtropical Water, which became a little higher in the Subantarctic Water and the maximum values of 0.50 and 0.24mg/m^3 were observed on the north side of the Antarctic Convergence (AC). The value was generally low in the open water south of the AC, but high values of 0.84 (58°S) and 0.58 (62°S) mg/m^3 were measured farther south of the AC in the southward and northward legs respectively. In or near the pack ice water, the chlorophyll α concentration formed a peak in the westward leg in December 1980 where the water temperature and salinity decreased. In a polynya surrounded by the fast ice, high values of 0.66 and 0.80mg/m^3 were recorded, whereas in the pack ice water, the value was low in the northward leg different from the results in the westward leg. These results suggest a relation between the chlorophyll α concentration and the presence of sea ice.