VARIABILITY OF PCO(2) IN THE TROPICAL ATLANTIC IN 1995

Atmospheric and oceanic partial pressures of CO2 (pCO(2)) have been re corded automatically along two Atlantic meridional transects in 1995. The tropical Atlantic ocean (20 degrees S-20 degrees N) is generally a source of CO2 for the atmosphere, but in the region of the North Equa torial Countercurrent an undersaturation of CO2 has been observed. Und ersaturations previously reported in the literature are explained by t he decrease of salinity due to the high precipitations associated with the Intertropical Convergence Zone. In June 1995, strong CO2 undersat urations (Delta pCO(2) = -70 mu atm) were observed near 8 degrees N, w hich suggests, in addition of the salinity effect, an uptake of CO2 du e to biological activity. This undersaturation, although weaker than i n spring, also appeared at other periods of the year 1995.