Nitrous oxide fluxes in Caribbean and tropical Atlantic waters:: evidence for near surface production

Nitrous oxide is recognized as a potent greenhouse gas and an intermediate in the destruction of stratospheric ozone, as well as a source of tropospheric ozone. We present data on the vertical and latitudinal distribution of nitrous oxide and estimation of fluxes across the sea-air and thermocline interfaces in tropical ocean waters north and south of Puerto Rico. Air-sea nitrous oxide fluxes computed from data collected during April 1995 and June 1996 are comparable to rates reported for marginal seas. However, close to 70% of the sea-air flux is not accounted for by cross-thermocline flux. Although the effect of physical processes cannot be ruled out as a factor in this differential at all locations, our observations provide evidence for active nitrous oxide production in near-surface tropical waters. (C) 2001 Published by Elsevier Science B.V.