SS1.03 Zooplankton Response to Climate Variability
Date: Monday, June 10, 2002
Time: 4:30:00 PM
Location: Lecture Theatre
 
MackasD, Inst. Ocean Sciences, Fisheries & Oceans Canada, Victoria, BC, Canada, mackasd@dfo-mpo.gc.ca
Tsurumi, M, , Inst. Ocean Sciences, Fisheries & Oceans Canada, Victoria, BC, Canada, tsurunim@dfo-mpo.gc.ca
Whitney, F, , Inst. Ocean Sciences, Fisheries & Oceans Canada, Victoria, BC, Canada, 
Wong, C, S, Inst. Ocean Sciences, Fisheries & Oceans Canada, Victoria, BC, Canada, 
 
PTEROPODS AND EDDIES IN THE ALASKA GYRE: A LINKAGE BETWEEN CLIMATE FORCING, ZOOPLANKTON POPULATION RESPONSE, AND VERTICAL FLUX OF CARBON
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Subarctic NE Pacific sediment trap time series contain intense, episodic peaks consisting primarily of pteropods (Limacina helicina and Clio pyramidata). Timing of the offshore pteropod sedimentation events is often about 1 year after ocean-margin El Nino events. We have identified an important coupling mechanism between these two. Satellite altimeter data show that large, anticyclonic eddies form each winter along the eastern margin of the subarctic Pacific, and then propagate westward into the Alaska Gyre. Our recent field surveys (springs and autumns of 2000 and 2001) show that pteropod abundance within the eddies is much higher than in surrounding oceanic waters, and that the cause of this abundance contrast is probably vertical positioning behavior of the pteropods (diel migration and turbulence avoidance) leading to aggregation and retention within the eddy. Eddy number, eddy size, and westward penetration are all greatest following El Nino events. We present estimates of the pteropod biomass associated with individual eddies, and compare these to the sediment flux time series from Ocean Station P in the central Alaska Gyre.