9314591 Cowen Carbon and Mineral Fluxes from Hydrothermal Plumes: Biogeochemical Linkages with the Upper Water Column Bioaccoustical surveys conducted near Endeavor Ridge over four consecutive years have revealed intense non-benthic zooplankton concentrations in a scattering layer immediately above the top of the spreading hydrothermal plume at depths of 1800 to 1900 m. Most exciting was the strong evidence for a 10 to 100 fold increase in zooplankton biomass in a 50 to 100 m thick layer immediately above the top of plume. This research project will examine the hypothesis that hydrothermal venting markedly influences the vertical distribution and composition of the zooplankton biomass beyond the limits of the vent field and plume depths. The project will use acoustic sensors and photographic equipment in combination with simultaneous net tows (1) to verify the distribution and composition of deep and mid-depth zooplankton scattering layers in the vicinity of Juan de Fuca Ridge in the North east Pacific; (2) determine the vertical distribution and composition of "marine snow" and establish its relation to the scattering layers; and (3) to investigate the magnitude and characteristics of ascending material fluxes from the plume depths. The resulting data will be evaluated with respect to the dynamics of potential carbon and mineral linkages between hydrothermal venting and the deep and mid-depth ocean water column. ***
