Oxygen Consumption, Denitrification, and Carbon Oxidation Rates In Near-Surface Sediments of the Arctic Ocean

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9400058 Christensen Research supported by this grant is under the auspices of the Arctic Systems Science (ARCSS) Global Change Research Program and is jointly sponsored by the Division of Ocean Sciences and the Office of Polar Programs. The research will be centered around a unique and intensive, multidisciplinary research expedition to parts of the Arctic Ocean that have never been extensively studied. The 1994 U.S./Canada Arctic Ocean Section is a collaborative effort with Canada that will involve approximately 60 scientists on a Canadian and a U.S. icebreaker during summer 1994. NSF-funded projects will focus on hydrography, biology, paleo-, and sea-ice studies. Data collected will be amongst the first ever from several regions of the Arctic Ocean and will be highly relevant to improving our understanding of how the Arctic is an indicator of changing global climate conditions and how it affects the physical, chemical, and biological features of the more temperate oceans and regions. This work is a component of the collaborative biology program. Research will be undertaken to determine the rates of oxygen consumption and carbon oxidation in sediments along the cruise track. Sedimentary oxidation rates are said to relate to the flux of usable organic matter from overlying surface waters. Hence, it is an indicator of primary production and possible transport of carbon and nutrients from the marginal regions. A series of box and piston cores will be taken and sub-samples provided to a number of PIs. Measurements will be made of key biogeochemical solutes (oxygen, nutrients, alkalinity, pH, soluble iron and manganese, sulfate, chloride, calcium, magnesium, sulfide (if present)) and solid constituents such as porosity, surface area, organic carbon and nitrogen, and carbonate. Sites to be sampled include continental shelves, slopes, abyssal plains, and mid-basin ridges. The data will be used to evaluate sediment-bottom water fluxes and to estimate rates of oxygen consumption, denitri fication, and carbon oxidation. Information will provide a greater understanding of the carbon budget and nitrogen budget in the Arctic and global ocean.