DYNAMICS OF PLANKTON GROWTH IN THE BARENTS SEA - MODEL STUDIES

1-D and 3-D models of plankton production in the Barents Sea are described and a few simulations presented. The 1-D model has two compartments for phytoplankton (diatoms and P. pouchetii), three for limiting nutrients (nitrate, ammonia and silicic acid), and one compartment called "sinking phytoplankton". This model is coupled to a submodel of the important herbivores in thc area and calculates the vertical distribution in a water column. Simulations with the 3-D model indicate a total annual primary production of 90-120 g C m-2 yr-1 in Atlantic Water and 20-50g C m-2 yr-1 in Arctic Water, depending on the persistence of the ice cover during thc summer. The 3-D model takes current velocities, vertical mixing. ice cover, and temperature from a 3-D hydrodynamical model. Input data are atmospheric wind, solar radiation, and sensible as well as latent heat flux for thc year 1983. The model produces a dynamic picture of the spatial distribution of phytoplankton throughout the spring and summer. Integrated primary production from March to July indicates that thc most productive area is Spitsbergenbanken and the western entrance to the Barents Sea, i.e. on the northern slope of Tromsoflaket.