Collaborative Research: Defining the Role of Biologically Produced Reactive Oxygen Species in Dark Mercury Cycling

汞（Hg）是一种有毒的微量元素，可在海洋食物网中生物积累，通过食用海鲜对人类健康构成威胁。然而，人们对汞在海洋中循环的控制知之甚少。迄今为止，大多数研究都集中在阳光照射和/或汞负载的环境中，光诱导的化学和汞电阻反应，分别已被确定为汞循环的主要途径。认为暗汞反应无关紧要的观点正在逐渐消失，现在很明显，暗氧化还原反应，包括还原和氧化，在汞的循环中很重要。在这项研究中，伍兹霍尔海洋研究所和科罗拉多矿业学院的研究人员将更好地了解海洋系统中汞（Hg）暗氧化还原转化的地球化学反应。研究人员将通过一系列实验室和实地调查，探索微生物活性、活性氧和汞形态之间的关系，以获得对暗汞循环的机械理解。通过确定海洋中汞氧化还原循环的新控制措施，这项研究将有助于为用于预测汞生物利用度的全球和生态系统模型提供信息。支持者计划对来自南波士顿波士顿绿色学院的高中教师进行汞地球化学教育，并让一名教师参加夏季研究巡航，以及开发科学课程，让学校中代表性不足的学生参与科学。 伍兹霍尔海洋学研究所的一名博士后和一名研究生以及科罗拉多矿业学院的一名研究生将得到支助和培训，作为该项目的一部分。 预计本科生将有机会作为暑期实习生参加这项研究。

Mercury (Hg) is a toxic trace element that bioaccumulates into marine food webs, imposing a health threat to humans through the consumption of seafood. However, controls on the cycling of Hg in the ocean are poorly understood. Most research to date has focused on sun-lit and/or Hg-laden environments, where light-induced chemical and mercury resistance reactions, respectively, have been identified as dominant pathways for Hg cycling. The paradigm that dark Hg reactions are irrelevant is fading and it is now apparent that dark redox reactions, both reduction and oxidation, are important in the cycling of Hg. In this study, researchers at the Woods Hole Oceanographic Institution and Colorado School of Mines will obtain a better understanding of the biogeochemical reactions responsible for dark redox transformations of mercury (Hg) in marine systems. The researchers will explore the relationship between microbial activity, reactive oxygen species, and Hg speciation in a series of laboratory- and field-based investigations to obtain a mechanistic understanding of dark Hg cycling. By identifying new controls on the redox cycling of Hg in the ocean, this research will help inform global and ecosystem models used to predict Hg bioavailability.Broader Impacts: The proponents plan to educate high school teachers from Boston Green Academy in South Boston on mercury biogeochemistry and have one teacher participate in the summer research cruises, as well as develop science curricula to engage the underrepresented students at the school in science. One postdoc and one graduate student from Woods Hole Oceanographic Institution and one graduate student from the Colorado School of Mines would be supported and trained as part of this project. It is anticipated that undergraduate students would have the opportunity to participate in the study as summer interns.