THE C-13 SUESS EFFECT IN THE WORLD SURFACE OCEANS AND ITS IMPLICATIONS FOR OCEANIC UPTAKE OF CO2 - ANALYSIS OF OBSERVATIONS AT BERMUDA

Surface ocean water delta(13)C measurements near Bermuda are examined in an attempt to find the annual decrease caused by the addition of an thropogenic CO2 to the atmosphere. We refer to this trend as the surfa ce ocean C-13 Suess effect. Interannual variability, which may be rela ted to the El Nino - Southern Oscillation in the Atlantic Ocean, is ap parent. We try to correct the data for this variability so as to bette r determine the trend. The trend has implications for the uptake of an thropogenic CO2 by the oceans. We employ a three-dimensional model of ocean chemistry to relate the trend at Bermuda to the average ocean tr end, then use the average ocean trend to estimate the vertical diffusi vity K in a one-dimensional ocean model, and finally use this model to calculate the oceanic uptake of CO2. Uncertainties associated with th e estimation of the Suess effect at Bermuda and in the analysis proced ure preclude a firm estimate of the oceanic uptake of CO2. Results are , in general, consistent with the low side of the Intergovernmental Pa nel on Climate Control estimation of 2.0 +/- 0.8 GtC yr(-1). With a lo nger record at Bermuda and delta(13)C observations at additional locat ions, we believe this approach will lead to a useful estimate of ocean ic uptake.