PLANKTON COMMUNITY RESPIRATION IN BRANSFIELD STRAIT (ANTARCTIC OCEAN)DURING AUSTRAL SPRING

Community respiration (R) was determined in Bransfield Strait from oxy gen changes in water samples incubated in borosilicate bottles maintai ned at in situ temperature. The respiratory electron transport system (ETS) activity of seawater communities was also measured from the same samples. Both data sets were related by the regression equation: log R (mg O-2 m(-3) day(-1)) = 0.462 + 0.730 x log ETS activity (mg O-2 m( -3) day(-1)) (r=0.80, n=23). From this equation and 37 ETS activity de pth profiles, we calculated the integrated (0-100 m) community respira tion as being in the range 1.2-4.5 g O-2 m(-2) day(-1) (mean=2.2). The se values do not differ significantly from other published results for the Arctic and Antarctic Oceans. Assuming a respiratory quotient of u nity, the areal respiration ranges between 0.45 and 1.69 g C m(-2) day (-1) (mean=0.8). This would represent an important sink for the primar y production reported for Bransfield Strait. The spatial distribution of community respiration showed higher values associated with the warm er and phytoplankton-rich waters outflowing from Gerlache Strait into Bransfield Strait, and with the front that separates Bellingshausen Se a waters from Weddell Sea waters. We suggest that this pattern of dist ribution may be related to the transport of organic matter by the Bran sfield Current along the front.