Determining the Stable Isotope Signatures of N2O In The Coastal Environments This Study will investigate the marine nitrous oxide (N2O) regime by taking advantage of the logistic opportunities provided by a funded experiment that will investigate nitrogen cycling in the suboxic waters of the eastern tropical Pacific Ocean. Specifically, the dual stable isotopic composition of N2O will be added to the suite of measurements that will be undertaken by Drs. A. Devol and P. Quay under a project entitled "Benthic carbon oxidation, denitrification and nitrogen isotope fractionation in continental margin sediments (OCE 9116275). The additional work will take advantage of a recently developed technique that permits the dual isotope composition of N2O to be determined from small samples. Measurements of the concentration of N2O in the suboxic water column of the eastern tropic Pacific Ocean will also be done.