A STRONG BIOLOGICAL RESPONSE TO OCEANIC FLOW PAST COBB SEAMOUNT

We report results of a CTD and chlorophyll a survey from Cobb Seamount, a shallow seamount in the northeast Pacific. Our results show a several-fold increase in the standing crop of chlorophyll a is centred over the seamount. Current meter and drifter data indicate an anticyclonic deflection of deep currents around Cobb consistent with a theoretical stratified Taylor cone. Cobb differs from other seamounts where similar phenomena have been reported (OWENS and HOGG, 1980, Deep-Sea Research, 27, 1029-1045; GOULD et al., 1981, Deep-Sea Research, 28, 409-440; GENIN and BOEHLERT, 1985, Journal of Marine Research, 43, 907-924) in that its summit penetrates well into the euphotic zone. A Taylor column existing at such shallow depths could locally enhance primary production, providing a significant source of energy for higher trophic levels on the seamount. Indirect evidence for such a scenario comes from observations of a high biomass benthic community on Cobb Seamount.