9415543 Childress This research is directed at testing the hypothesis that the remineralization of oceanic carbon by micronekton and zooplankton is a significant fraction of the oceanic carbon budget. This will be carried out by applying the data on metabolic patterns to a midwater animals biomass dataset which has been collected in the California Current in a 4100 m water column and using the metabolic data to estimate respiratory carbon flux due to this community and its major components. The research effort will focus on improved biomass estimates for gelatinous animals, improved estimations of metabolic rates at the low oxygen partial pressures found in midwater oxygen minimum layers, and collection of data from rarer and more fragile species. The significance of this research is tied to the importance of understanding the immense, global midwater ecosystem. An ecosystem which interacts extensively with the surface communities, but about which we know relatively little. The midwater fauna (including both micronekton and zooplankton) is a major factor in the flux of material through the water column as a result of vertical migration, predation on vertical migrnats, feeding on sedimenting materials and production of biomass and feces at depth. The respiratory oxidation of organic compounds at depth by this fauna is potentially a significant component of the carbon flux in midwater. To understand the importance of this assemblage of organisms in the economy of the ocean and in global carbon cycles, it is essential to obtain information on the rates of biological processes carried out by this fauna.
