REGIONALLY AND SEASONALLY DIFFERENTIATED PRIMARY PRODUCTION IN THE NORTH-ATLANTIC

A bio-geochemical classification of the N. Atlantic Basin is presented according to which the basin is first divided into four primary algal domains: Polar, West-Wind, Trades and Coastal. These are in turn sub- divided into smaller provinces. The classification is based on differe nces in the physical environment which are likely to influence regiona l algal dynamics. The seasonally-differentiated parameters of the phot osynthesis-light curve (P-l curve) and parameters that define the vert ical structure in chlorophyll profile are then established for each pr ovince, based on an analysis of an archive of over 6000 chlorophyll pr ofiles, and over 1800 P-I curves. These are then combined with satelli te-derived chlorophyll data for the N. Atlantic, and information on cl oud cover, to compute primary production at the annual scale, using a model that computes spectral transmission of light underwater, and spe ctral, photosynthetic response of phytoplankton to available light. Th e results are compared with earlier, satellite-derived, estimates of b asin-scale primary production.