Benthic Processes in the Equatorial Pacific

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A study is proposed at improving knowledge of rain rates, remineralization rates, and burial rates in the abyssal environment, and extending understanding of the processes which control these rates and thereby fix sediment composition. The three fluxes will be measured in a 19-station transect across the equatorial Pacific, from 15oN to 15oS at 135oW. This transect crosses gradients in major parameters governing fluxes at the seafloor, including wind patterns (controlling aerosol input), surface water productivity (controlling rain rates of biogenic constituents), and botton water CaC0 3 undersaturation (governing CaC0 3 preservation). The experiment plan involves determining benthic fluxes of major biogenic constituents (from high resolution interfacial pore water studies) and sedimentary accumulation rates of aerosol and biogenic constituents (from studies of sediment compositition and sedimentation rates). Rain rates will be calculated as the sum of the benthic fluxes and accumulation rates. Aerosol samples will be collected along the cruise track for subsequent mineralogical and chemical analyses. The results will contribute to several major problems in oceanography. First, they will greatly extend knowledge of the rain rates of biogenic constituents by providing data for an important area encompassing a range of globally important uppper ocean and deep ocean regimes. Second, the results will provide data for testing and extending models and hypotheses about the processes which govern the rates of benthic processes and the chemical composition of the sediments. Finally, the data will provide detailed information on the contemporary relation between upper water column processes, atmospheric circulation, and sediment deposition in the study area, thereby dramically enchancing our ability to do paleoceanographic reconstructions in the equatorial Pacific.