Collaborative Research: The Biogeochemical Evolution of Dissolved Organic Matter in a Fluvial System on the Cotton Glacier, Antarctica

溶解有机物质(DOM)由地球上大量的有机碳库组成，使活的水生生物中的有机碳量相形见绌。DOM的性质和反应活性尚未很好地确定，也没有观察到原生DOM在淡水中由其前体物质演变而来的过程。最近对横跨北极山脉的科顿冰川上形成的冰上溪流的采样显示，根据其UV-Vis和荧光光谱，DOM更类似于可识别的前体有机化合物的组合。有人认为，随着时间的推移，这种水中的DOM演变成类似于海洋和许多内陆表层水域中存在的物质。该系统的暂时性，即它的季节性改革，也防止了大多数地表水中存在的难熔DOM的任何积累。因此，棉花冰川为我们研究前体物质形成DOM提供了独特的环境。一个跨学科的团队将研究这种前体DOM的生物地球化学，以及微生物是如何修改它的。通过将重点放在DOM从前体物质向更腐殖化部分转变的化学组成上，研究人员将把这种转变与生物利用度、酶活性、群落组成和微生物生长效率联系起来。该项目将支持各级教育，包括K-12、高中、本科生、研究生和博士后，并将增加未被充分代表的群体对科学的参与。为了实现这些目标，调查人员已经与女子学校和美洲原住民项目建立了关系。将与PolarTREC、PolarPalooza以及南极艺术家和作家(如有可能)协调开展更多的外联活动。

Dissolved organic matter (DOM) comprises a significant pool of Earth's organic carbon that dwarfs the amount present in living aquatic organisms. The properties and reactivity of DOM are not well defined, and the evolution of autochthonous DOM from its precursor materials in freshwater has not been observed. Recent sampling of a supraglacial stream formed on the Cotton Glacier in the Transantarctic Mountains revealed DOM that more closely resembles an assemblage of recognizable precursor organic compounds, based upon its UV-VIS and fluorescence spectra. It is suggested that the DOM from this water evolved over time to resemble materials present in marine and many inland surface waters. The transient nature of the system i.e., it reforms seasonally, also prevents any accumulation of the refractory DOM present in most surface waters. Thus, the Cotton Glacier provides us with a unique environment to study the formation of DOM from precursor materials. An interdisciplinary team will study the biogeochemistry of this progenitor DOM and how microbes modify it. By focusing on the chemical composition of the DOM as it shifts from precursor material to the more humified fractions, the investigators will relate this transition to bioavailability, enzymatic activity, community composition and microbial growth efficiency. This project will support education at all levels, K-12, high school, undergraduate, graduate and post-doc and will increase participation by under-represented groups in science. Towards these goals, the investigators have established relationships with girls' schools and Native American programs. Additional outreach will be carried out in coordination with PolarTREC, PolarPalooza, and if possible, an Antarctic Artist and Writer.