OBSERVATIONS ON THE PELAGIC SYSTEM IN THE TROPICAL ATLANTIC AT 20-DEGREES-N (THE EUMELI PROGRAM)

Research during the EUMELI program aimed at comparing primary producti on and the vertical flux in an oligotrophic regime with that of a meso trophic site, in order to design a model of the functioning of the sys tem to serve in the interpretation of future satellite data. Prelimina ry results reinforce the concept of new production-regenerated product ion, the greatest part of photosynthesised carbon (low level of produc tion < 50 g C m-2 y-1) being rapidly recycled in the superficial layer . By comparing the oligotrophic and the mesotrophic sites, the followi ng ratios were obtained: chlorophyll biomass = 1/2; total production ( C-14) = 1/3; exported flux = 1/7; flux arriving in deep waters = 1/15.