Collaborative Research: Seawater Inorganic and Organic Carbon Measurements for the US GEOTRACES Eastern Pacific Zonal Transect

来自百慕大海洋科学研究所和加州大学圣巴巴拉分校的科学家计划在2013年GEOTRACES东太平洋地带性样带邮轮期间收集样本，并分析它们的溶解无机碳、溶解有机碳(DOC)和总碱度。由此产生的数据将非常精确和准确，以便计算pH值和海水碳酸盐化学(例如，氢氧化物、碳酸盐离子、碳酸钙矿物的饱和度)。鉴于pH对氧化还原化学、形态形成以及配体-颗粒-痕量金属/同位素相互作用的影响，从秘鲁到大溪地的横断面及其海洋海水碳酸盐化学范围将提供一个机会来检验以下假设：(1)pH是控制痕量元素及其同位素(TEI)在水柱内的分布及其动态的关键约束条件；(2)DOC与TEI相互作用，提供影响微量元素溶解、络合和形态形成的结合配体的光谱。此外，由于邮轮航道将经过东太平洋隆起，科学家们计划评估热液羽流中DOC的可变性，并确定有机物在DOC和颗粒有机碳之间的分配。在与GEOTRACES其他研究人员的合作下，这些数据将用于评估铁、铜、钴和汞的形态，并在迈阿密大学罗森斯蒂尔海洋和大气科学学院的合作者获得的氯氟烃数据的帮助下，确定表层海洋中DOC的去除率。至于更广泛的影响，该项目将产生一个高质量的数据集，这不仅将使地球观测和观测系统社区受益，帮助他们解释其痕量金属和同位素测量结果，而且也将使参与有机/无机碳循环研究的其他科学家受益。加州大学圣巴巴拉分校的一名研究生将作为该项目的一部分得到支持和培训。

Scientists from Bermuda Institute of Ocean Sciences and the University of California, Santa Barbara, plan to collect samples during the 2013 GEOTRACES Eastern Pacific Zonal Transect cruise and analyze them for dissolved inorganic carbon, dissolved organic carbon (DOC), and total alkalinity. The resultant data will be highly precise and accurate to allow calculation of pH and seawater carbonate chemistry (e.g., hydroxide, carbonate ion, saturation sate for calcium carbonate minerals). Given the influence of pH on redox chemistry, speciation, and ligand-particle-trace metal/isotope interactions, the transect from Peru to Tahiti with its range of marine seawater carbonate chemistry will provide an opportunity to test the hypotheses that (1) pH is a critical constraint for controlling distributions of trace elements and their isotopes (TEIs) and their dynamics within the water column, and; (2) DOC interacts with TEIs providing a spectrum of binding ligands that influence trace element solubility, complexation, and speciation. Also, because the cruise track will pass over the East Pacific Rise, the scientists plan to evaluate DOC variability within the hydrothermal plume and determine the partitioning of organic matter between DOC and particulate organic carbon. In collaboration with other GEOTRACES researchers, the data will be used to assess the speciation of iron, copper, cobalt and mercury, as well as determine the removal rate of DOC from the surface ocean with the help of chlorofluorocarbon data obtained by a collaborator from the University of Miami, Rosenstiel School of Marine and Atmospheric Science. As regards broader impacts, this project would result in a high quality data set that would benefit not only the GEOTRACES community to help them interpret their trace metal and isotope measurements but other scientists involved in organic/inorganic carbon cycle research as well. One graduate student from the University of California, Santa Barbara would be supported and trained as part of this project.