Collaborative Research: GEOTRACES Arctic Section: Mercury Speciation and Cycling in the Arctic Ocean

合作研究：GEOTRACES 北极部分：北冰洋的汞形态和循环

• 批准号: 1434650
• 负责人: Chad Hammerschmidt
• 金额: $ 17.88万
• 依托单位: Wright State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1434650&HistoricalAwards=false
• 关键词: Collaborative; Research; GEOTRACES; Arctic; Section

In this project, investigators from Woods Hole Oceanographic Institution and Wright State University participating in the 2015 U.S. GEOTRACES Arctic expedition will measure total mercury and mercury species in seawater, particles, sediments, snow and ice samples to better understand its cycling in the Arctic Ocean. In common with other multinational initiatives in the International GEOTRACES Program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. In its methylated form, mercury poses a serious human and ecosystem health threat, and this research will provide important information on the extent and rate of change of mercury in the sensitive Arctic ecosystem. Results from this study will be shared through outreach efforts to middle schools students in the Dayton, Ohio area, and the research will involve training for graduate and undergraduate students. Mercury is a toxic trace metal that originates from natural and anthropogenic sources, and can enter the oceans through many processes, most importantly atmospheric deposition, riverine discharge, and coastal erosion in the Arctic Ocean. Mercury in the ocean can be transformed into varying species by a variety of abiotic and biotic processes. Its transformation to methylmercury is of primary concern as it can biomagnify in food webs. Wildlife in the Arctic has experienced unprecedented increases of methylmercury in their tissues during the past 200 years. While there has been a great deal of research related to mercury cycling in the Arctic in recent years, there remain large gaps in fundamental understanding, particularly with respect to mercury distributions and speciation. The researchers will 1) measure the concentration of four mercury species in the water column, particles, sediments, snow and sea ice samples, 2) determine the concentration of other related chemical species (thiols and snow/ice bromine), and 3) explore the mercury-related genomics of bacteria in various samples. Results from this work will yield new insights into the extent and rate of change of mercury loadings in the Arctic Ocean.

在该项目中，参加2015年美国GEOTRACES北极考察的伍兹霍尔海洋研究所和莱特州立大学的研究人员将测量海水、颗粒、沉积物、雪和冰样本中的总汞和汞种类，以更好地了解其在北冰洋的循环。与国际地理追踪计划中的其他多国倡议一样，美国北极探险的目标是识别控制海洋中关键微量元素和同位素分布的过程和量化通量，并确定这些分布对不断变化的环境条件的敏感性。有些微量元素是生命所必需的，有些是已知的生物毒素，还有一些很重要，因为它们可以用作海洋中各种物理、化学和生物过程的示踪剂。甲基化形式的汞对人类和生态系统健康构成严重威胁，这项研究将为敏感的北极生态系统中汞的变化程度和速度提供重要信息。这项研究的结果将通过俄亥俄州代顿地区中学生的外展活动分享，并且研究将涉及对研究生和本科生的培训。汞是一种有毒的微量金属，来源于自然和人为来源，可以通过许多过程进入海洋，最重要的是大气沉积、河流排放和北冰洋海岸侵蚀。海洋中的汞可以通过各种非生物和生物过程转化为不同的物种。它向甲基汞的转变是首要关注的问题，因为它可以在食物网中生物放大。过去 200 年来，北极野生动物组织中的甲基汞含量空前增加。尽管近年来进行了大量与北极汞循环相关的研究，但在基本认识方面仍然存在很大差距，特别是在汞分布和形态形成方面。研究人员将1）测量水柱、颗粒、沉积物、雪和海冰样品中四种汞的浓度，2）确定其他相关化学物质（硫醇和雪/冰溴）的浓度，3）探索各种样品中与汞相关的细菌基因组学。这项工作的结果将为北冰洋汞含量变化的程度和速度提供新的见解。