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

研究人员提议利用三个已经资助的研究探险，调查北冰洋天然溶解有机物质(DOM)循环的分布，特别是它与铁等痕量金属循环的关系。北冰洋在过去30年里经历了重大变化，包括海冰减少和大陆径流增加。北极被认为是碳循环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种根本性变化知之甚少。这项拟议的研究将为了解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运输和命运密切相关，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扮演着重要角色。2015年，在USCGC Healy、德国破冰船Polarstein和日本研究船Mirai上进行的三次探险期间，将收集并分析水样中溶解的有机碳和氮、氨基酸、木质素酚以及发色DOM(CDOM)的详细光学特征。结合光学和分子分析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。用于测量DOM的原位荧光的探头将与CTD/玫瑰花结相连，用于高分辨率测绘和实时检查感兴趣的特征，以指导采样工作。美国和德国的探险是国际GEOTRACES计划的一部分，该计划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通量，并确定这些分布对不断变化的环境条件的敏感性。美国北极地质研究项目已经为这一研究项目建立了一个中央外展计划，包括与阿拉斯加当地社区会面，招募一名高中教师参加探险，并通过博客与美国和其他地方的学校互动。这些调查人员将与现有的GEOTRACES外联工作挂钩，并将感兴趣的德克萨斯州和南卡罗来纳州学校链接到探险博客。该项目将培训3000名研究生，并让约6000名本科生参与北冰洋的研究。这个项目的教学部分的目标是为学生提供一种演示科学方法的体验，从目标和假设的制定到实验设计和结果的展示。这个项目的结果将通过与当地报纸建立的联系向公众传达，学生们在那里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.