GEOTRACES Zonal Atlantic Section: Arsenic and phosphorus biogeochemistry

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GEOTRACES is a newly initiated international oceanographic program to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the oceans and to establish an understanding of the sensitivity of these distributions to changing environmental conditions. A scientist from Old Dominion University plans to participate in the 2010 North Atlantic GEOTRACES cruise to collect and analyze samples for arsenic and phosphorus with the goal of quantifying the biogeochemical linkages between these two elements. The specific research objectives are the following: (1) establish the correlations between measured dissolved arsenate:phosphate ratios and the concentrations of arsenite, monomethyl-arsenic, and dimethyl-arsenic; (2) quantify the surface water residence times of arsenite, monomethyl-arsenic, and dimethyl- arsenic with respect to photo-oxidation and demethylation; (3) evaluate the efficacy of using the concentrations of arsenite, monmethyl-arsenic, and/or dimethyl-arsenic as proxies for phosphate stress; and (4) construct a biogeochemical budget for dissolved As in the North Atlantic that will allow the effect of P on As cycling to be quantified. As regards broader impacts, one postdoc and one undergraduate student will be supported and trained as part of this project.