Collaborative research: Does dissolved organic matter influence the concentrations and distributions of trace elements in the Arctic Ocean?

研究人员建议利用三个已经资助的研究考察，调查北冰洋天然溶解有机物（DOM）循环的分布，特别是其与铁等微量金属循环的关系。北冰洋在过去30年中经历了重大变化，包括海冰减少和大陆径流增加。北极被认为是碳和水文循环变化的先兆，对区域和全球气候具有重要影响。人们对北冰洋的物理、化学和生物结构将如何应对这些根本性变化知之甚少。这项研究将为溶解有机物及其在微量元素循环中的作用提供新的见解。最近的研究提供了诱人的数据，表明DOM和痕量金属在北冰洋的迁移和归宿密切相关，并表明大陆径流和海冰形成在DOM和相关痕量金属的分布中起重要作用。将收集水样并分析溶解有机碳和氮，氨基酸，木质素酚和发色DOM（CDOM）的详细光学表征在2015年的3次考察期间，在USCGC Healy，德国破冰船Polarstern和日本研究船米拉伊上进行。光学分析和分子分析相结合，将用于区分和量化陆源和海洋DOM及其与微量元素的潜在相互作用。一个用于测量DOM原位荧光的探头将与CTD/玫瑰花结连接，以便对感兴趣的特征进行高分辨率绘图和实时检查，以指导采样工作。美国和德国的考察是国际GEOTRACES计划的一部分，其目标是确定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，并确定这些分布对环境条件变化的敏感性。美国北极GEOTRACES项目已经为这项研究计划建立了一个中心外展计划，包括与阿拉斯加当地社区的会议，招募一名高中教师参加探险，并通过博客与美国及其他地区的学校互动。这些调查人员将与现有的GEOTRACES外展工作联系起来，并将感兴趣的德克萨斯州和南卡罗来纳州学校与探险博客联系起来。该项目将培训3名研究生，并让大约6名本科生在北冰洋进行研究。该项目的教学部分的目标是为学生提供一种体验，展示科学方法，从目标和假设的发展到实验设计和结果的呈现。该项目的调查结果将通过与当地报纸建立的联系向公众传达，学生们用自己的话描述研究项目。

The investigators propose to take advantage of three already-funded research expeditions to investigate the distribution of cycling of natural dissolved organic material (DOM) in the Arctic Ocean and in particular its relationship to the cycling of trace metals such as iron. The Arctic Ocean has experienced significant changes over the last 30 years, including declining sea ice and increasing continental runoff. The Arctic is considered a harbinger of changes in the carbon and hydrological cycles, with important implications for regional and global climate. How the physical, chemical and biological structure of the Arctic Ocean will respond to such fundamental changes is poorly understood. The proposed research will provide novel insights about dissolved organic matter and its role in trace element cycling. Recent studies provide tantalizing data indicating the transport and fate of DOM and trace metals are closely linked in the Arctic Ocean, and suggesting an important role of continental runoff and sea ice formation in the distribution of DOM and associated trace metals.Water samples will be collected and analyzed for dissolved organic carbon and nitrogen, amino acids, lignin phenols and detailed optical characterization of chromophoric DOM (CDOM) during 3 expeditions in 2015 aboard the USCGC Healy, the German ice breaker Polarstern, and the Japanese research vessel Mirai. The combined optical and molecular analyses will be used to distinguish and quantify terrigenous and marine DOM and their potential interactions with trace elements. A probe for measuring in situ fluorescence of DOM will be interfaced with the CTD/rosette for high-resolution mapping and real-time examination of interesting features to guide sampling efforts. The U.S. and German expeditions are part of the international GEOTRACES program, whose goals 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. The U.S. Arctic GEOTRACES project has established a central outreach program for this research program including meetings with local communities in Alaska, recruiting a high school teacher to participate in the expedition and interact with schools in the US and beyond via a blog. These investigators will tie into the existing GEOTRACES outreach efforts and will link interested Texas and South Carolina Schools to the expedition blog. This project will train 3 graduate students in and expose about 6 undergraduate students to research in the Arctic Ocean. The goal of the teaching component of this project is to provide students with an experience that demonstrates the scientific method, from development of goals and hypotheses to experimental design and presentation of results. Findings of this project will be conveyed to the public using established links with local newspapers where students describe research projects in their own words.