Vertical particle flux on the shelf off northern Spitsbergen, Norway
Suspended and sedimented particulate matter was examined alongtransects on the continental shelf off northern Spitsbergen, Norway, during summer1991. The transects were situated in non-ice-covered areas dominated by Atlanticwater, areas with multi-year ice and the marginal ice zone. The variability of thesedimented matter with regard to composition, quantity and quality between the 7investigated stations was considerable. The open Atlantic water showed the highestsuspended biomass [100 to 280 mg particulate organic carbon (POC) m-3] and thevertical flux was moderate (24 to 30 mg POC m-2 d-1) and dominated by faecalmatter. While the suspended biomass in areas covered by multi-year ice was low(<65 mg POC m-3), the vertical flux was relatively high (18 to 76 mg POC m-2d-1) and dominated by terrestrial organic and faecal matter. The contribution ofphytoplankton cells to the vertical flux of POC was small in areas covered bymulti-year ice, on average about 1%. The contribution of phytoplankton cells to thevertical flux in the marginal ice zone was higher (5.6% of POC), consisting mainlyof Chaetoceros socialis and Fragilariopsis sp., but a considerable amount of faecalmatter also settled. At all stations zooplankton strongly influenced the vertical flux,not only by faecal pellet production but probably also by direct mediation of fluxes(e.g. coprophagy).