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

点击翻译按钮获取中文摘要

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.