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The surface distribution of CH4, photoproduction capacity of seawater for CO, and CH 4 and CO microbial oxidation rates and turnover times were determined for the surface waters of the southeastern Caribbean Sea and Gulf of Pafia as affected by the Orinoco River. Measurements were made during the spring (low fiver flow) and the fall (high fiver flow) in order to determine the influence of Orinoco River discharge on these parameters. Methane concentrations were generally lower in the fall than in the spring.L ow CH 4 oxidationr ates and similars urfaced istributionsw ere observedd uring both seasons. Methane oxidation in the fiver plume was significantly higher in the fall. Potential CO photoproduction and CO oxidation rates were generally higher during the fall. Possible effects of the Orinoco River on potential CO photoproduction capacity were observed as far as Puerto Rico. Turnover times for CH 4 were in the order of years, whereas CO turnover times were in the order of hours. The Orinoco River has a significant impact on the consumption of CO and CH 4 and the photoproduction of CO in the southeastern Caribbean Sea, presumably resulting from inputs of fivefine carbon and nutrients.

Publisher Statement

An edited version of this paper was published by AGU. Copyfight 1993 by the American Geophysical Union.