Seasonal phytoplankton development and new production in the central Greenland Sea

The seasonal development of the phytoplankton in the central Greenland Sea, based on sampling at different time intervals in the period 1993-1995, is consistent with patterns observed in adjacent similar regions. Phytoplankton growth started in early May and developed gradually through May reaching a peak in early June. The spring phytoplankton was mainly composed of diatoms and the prymnesiophyte Phaeocystis pouchetii. Spring primary production rates, its determined by the radioactive carbon method, averaged 752 mg C m(-2) d(-1) during May and June. The summer situation was characterised by strong stratification and an upper mixed layer of about 30 metres that became completely depleted of nutrients and contained low phytoplankton biomass by August. New production in the growing season from May to August, estimated from the total production and published f-ratios was 52 g C m(-2), while new production estimated from the disappearance of nitrate in the same period, along a transect across the central Greenland Sea, was 62 g C m(-2). These results are in good agreement with those from previous investigations and provides the basis for an assessment of the role of biology on the carbon cycling in the central Greenrand Sea when discussed in relation to the inorganic carbon cycling and related biological processes in the area.