Rust, T. M.. University of Hawaii, trust@soest.hawaii.edu
Popp, B. M.. University of Hawaii, popp@soest.hawaii.edu

 
DISTRIBUTIONS AND ISOTOPIC COMPOSITIONS OF NITROUS OXIDE IN THE SUBANTARCTIC SOUTHERN OCEAN
 
Nitrous oxide is an atmospheric greenhouse gas that on a molecule per molecule basis has the potential to contribute more to the greenhouse effect than carbon dioxide. Nitrogen and oxygen isotopic compositions of nitrous oxide can constrain origins and the sea-to-air flux of nitrous oxide in marine surface waters. We have measured for the first time the concentrations and the nitrogen and oxygen isotopic compositions of nitrous oxide in surface waters and in the marine boundary layer along a north-south transect in the Sub-Antarctic Zone of the Southern Ocean south of Tasmania as part of the Australian JGOFS Program. Recent isotopic results from the Arabian Sea (Naqvi et al., 1998; Nature, 394:462-464) and the oligotrophic North Pacific gyre (Dore et al., 1998; Nature, in press) indicate that microbial nitrification plays a strong role in controlling the isotopic composition of tropospheric nitrous oxide. We will (1) compare isotopic compositions of nitrous oxide from the Southern Ocean with these results, (2) determine the sea-to-air flux of nitrous oxide north and south of the Subantarctic Front and (3) discuss implications of these results for the mechanism of nitrous oxide formation.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS32TU0961S