Effects of Polychlorinated Biphenyls (PCBs) on a Marine Plankton Population and Sedimentation in Controlled Ecosystem Enclosures

Abstract

Effects of PCBs on a natural marine ecosystem were studied employing controlled ecosystem enclosures (CEEs) which contained 68 m super(3) of seawater and the natural sea-water biota (Saanich Inlet, British Columbia, Canada). Following addition of PCBs (50 mu g 1 super(-) super(1)) to a CEE, primary productivity was initially reduced by PCBs to less than 30% of the control CEE to which no PCBs had been added. Settling velocity of particulate matter was initially accelerated by PCB addition, but gross sedimentation decreased due to inhibition of primary productivity. Decomposition activity in sedimented matter was initially inhibited by PCBs, one order of magnitude lower than that of the control, but followed by recovery to the control level within 6-10 d. Drastic and chronic reductions in the size of zooplankton stocks were also attributed to PCB stress.