Collaborative Research: Interwoven Biogeochemical Cycles and Biological Transformations of Mercury and Selenium in the Upper Ocean

来自康涅狄格大学、伍兹霍尔海洋研究所和哈佛大学的研究人员计划解决与全球汞和硒地球化学循环有关的三个问题：（1）海洋上层形成甲基化汞和硒化合物的非生物和生物机制是什么？(2)光化学反应在汞和硒的海气交换中的作用是什么？（3）Hg和Se的地球化学循环是如何联系的？ 为了实现他们的目标，科学家们将参加到热带北太平洋的机会巡航，以及进行实验室培养和控制孵化实验。 航行期间收集的样本将用于确定汞和硒的形态，并获得光化学状态的测量结果（即，紫外线、臭氧、光照水平、化学物质（即，天然有机物，氧化还原金属），和生物（即，叶绿素a、浮游植物组成、蛋白质组学、碳矿化的估计）特性。 实验室培养和控制培养实验将用于确定汞和硒化合物形成和降解的具体途径，特别是光化学转化的作用，以及评估硒作为汞在海洋环境中的结合配体的重要性。 最后，研究人员将继续开发GEOS-Chem全球生物化学汞模型的海洋子模型，以包括硒的循环，并将使用该模型来确定这两种元素的全球循环中各种转换和逃逸过程的重要性。 至于更广泛的影响，这项研究具有社会效益，因为它将提高我们对汞如何进入影响人类健康的海产品的理解。 研究结果将列入教材。 作为该项目的一部分，康涅狄格大学的一名研究生、哈佛大学的一名博士后和伍兹霍尔海洋学研究所的一名研究生将得到支助和培训。

Researchers from the University of Connecticut, Woods Hole Oceanographic Institution, and Harvard University plan to address three questions related to the global biogeochemical mercury (Hg) and selenium (Se) cycles, namely (1) what are the abiotic and biotic mechanisms for formation of methylated Hg and Se compounds in the upper ocean?; (2) what is the role of photochemical reactions in air-sea exchange of Hg and Se?; and (3) how are the biogeochemical cycles of Hg and Se related? To attain their goal, the scientists will participate in a cruise of opportunity to the Tropical North Pacific, as well as carry out laboratory culture and controlled incubation experiments. Samples collected during the cruise will be used to determine the speciation of Hg and Se, as well as obtain measurements of photochemical status (i.e., UV, ozone, light levels, chemical (i.e., natural organic matter, redox metals), and biological (i.e., chlorophyll a, phytoplankton composition,proteomics, estimates of carbon mineralization) properties. The laboratory culture and controlled incubation experiments will be used to determine the specific pathways for Hg and Se compound formation and degradation, especially the role of photochemical transformations, as well as assess the importance of Se as a binding ligand for Hg in the marine environment. Lastly, the researchers will continue to develop the oceanic sub-model of the GEOS-Chem global biochemical Hg model to include the cycling of Se and will use the model to ascertain the importance of various processes of conversion and evasion in the global cycles of these two elements. As regards broader impacts, this study has societal benefits because it would improve our understanding on how mercury enters seafood which impacts human health. Results from the research would be included in curriculum material. One graduate student from the University of Connecticut, one postdoc from Harvard University, and one graduate student from Woods Hole Oceanographic Institution would be supported and trained as part of the project.