Bacterioplankton production in the nearshore zone during upwelling off central Chile

Abstract

The authors measured bacterioplankton abundance and productivity during 3 upwelling cycles at a nearshore station off central Chile (36 degree 30'S) in January 1986. Standing stock (43 to 113 x 10 super(12) cells m super(-2) over the 25 m water column) and productivity were lowest during periods of active upwelling and highest during periods of calm or light winds and water column stratification. Bacterial productivity peaked 1 to 2 d after primary productivity and varied by about an order of magnitude (0.13 to 1.40 mu gC 1 super(-1) h super(-1)) between newly upwelled and stratified waters. Surface primary productivity was much more variable and thus appeared to respond more strongly to the hydrographic events of the upwelling cycle. Net bacterial production was often a substantial fraction of primary production (up to about 50%), especially in newly upwelled water.