GEOTRACES Zonal Atlantic Section: Arsenic and phosphorus biogeochemistry

GeoTraces是一个新发起的国际海洋学方案，目的是确定控制海洋中关键微量元素和同位素分布的过程和通量，并建立对这些分布对不断变化的环境条件的敏感性的理解。老道明大学的一名科学家计划参加2010年北大西洋地学研究巡航，收集和分析砷和磷的样本，目标是量化这两种元素之间的生物地球化学联系。具体的研究目标如下：(1)建立测量的溶解砷：磷比例与亚砷酸盐、单甲基砷和二甲基砷的浓度之间的关系；(2)量化亚砷酸盐、单甲基砷和二甲基砷在地表水中的光氧化和去甲基化停留时间；(3)评估使用亚砷酸盐、单甲基砷和/或二甲基砷的浓度作为磷酸盐胁迫的替代物的有效性；以及(4)建立北大西洋溶解砷的生物地球化学预算，以便量化P对As循环的影响。至于更广泛的影响，作为该项目的一部分，将支持和培训一名博士后和一名本科生。

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.