Net community production and oxygen fluxes in the Nordic Seas based on O-2budget calculations

Historical hydrographic data from 1955 to 1988 are applied to an oxygen mod el for the euphotic zone in an attempt to estimate the net community produc tion in the Nordic Seas (Greenland, Iceland, and Norwegian Seas). The model requires prior knowledge of the net annual oxygen flux through the sea sur face, which is achieved by an oxygen budget based on volume transports from the literature and observed oxygen concentrations. A net annual uptake of approximately 2.3 mol O-2 m(-2) is needed to balance the budget, indicating that the region acts as a sink for atmospheric oxygen. An oxygen budget fo r the euphotic zone is then compiled on the basis of observed monthly mean changes in oxygen content, which are assumed to be balanced by net air-sea oxygen exchange and net community production. Vertical exchange through the bottom of the euphotic zone and horizontal transports are ignored. The mea n net community production in the Nordic Seas is found to be 36 g C m(-2) y (-1), but this result is sensitive to variations in the calculated oxygen f luxes which arise from the uncertainty of the parameterization of the air-s ea gas exchange.