9402538 Ward This proposal will investigate the relationship between the oceanic oxygen minimum zone and denitrification and nitrification using a combination of traditional 15N tracer methods and immunological probes t characterize the distribution of the bacterial assemblages involved in the transformations. The study site in the Eastern Tropical North Pacific (ETNP) will present a range of conditions including well oxygenated surface waters, oxygen minima of varying intensities, and oceanic deep water. Due to the small scale sampling and smaller volume incubations made possible by improved isotope probes, the investigators will study the bacteriological properties on a scale approaching that possible for chemical variables. This will allow a determination of the extent to which nitrification and denitrification overlap and interact in the spectrum of oxygen conditions of the ETNP.
