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

溶解有机物（DOM）是地球有机碳的重要组成部分，其含量使活的水生生物中存在的量相形见绌。DOM的性质和反应性还没有很好的定义，并且还没有观察到原生DOM从其淡水前体物质的演变。最近的采样上形成的棉花冰川在跨南极山脉的冰川流显示DOM，更接近类似于一个可识别的前体有机化合物的组合，根据其紫外-可见光谱和荧光光谱。有人建议，DOM从这个水演变随着时间的推移，类似的材料存在于海洋和许多内陆表面沃茨。系统的瞬态特性，即，它季节性地重新形成，也防止了大多数表面沃茨中存在的难降解DOM的任何积累。因此，棉花冰川为我们提供了一个独特的环境，研究DOM的形成从前体物质。一个跨学科的团队将研究这一前体DOM的生物地球化学以及微生物如何改变它。通过关注DOM从前体物质转变为更腐殖化部分时的化学组成，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，从幼儿园到12年级、高中、本科、研究生和博士后，并将增加代表性不足的群体对科学的参与。为了实现这些目标，调查人员与女子学校和美洲原住民项目建立了关系。将与PolarTREC、PolarPalooza协调开展更多的外联活动，如果可能的话，还将与南极艺术家和作家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.