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

溶解有机物 (DOM) 包含大量地球有机碳，其含量使活水生生物中的有机碳相形见绌。 DOM 的性质和反应性尚未明确定义，并且尚未观察到淡水中原生 DOM 从其前体材料的演化。最近对横贯南极山脉科顿冰川上形成的冰上溪流进行的采样显示，根据其紫外-可见光和荧光光谱，DOM 更类似于可识别的前体有机化合物的组合。有人认为，这种水中的 DOM 随着时间的推移而演变，类似于海洋和许多内陆地表水中存在的物质。该系统的瞬态性质，即季节性重组，也防止了大多数地表水中存在的难降解 DOM 的积累。因此，棉花冰川为我们提供了一个独特的环境来研究前体材料中 DOM 的形成。一个跨学科团队将研究这种 DOM 祖先的生物地球化学以及微生物如何改变它。通过关注 DOM 从前体材料转变为更腐殖质部分时的化学成分，研究人员将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。该项目将支持各个级别的教育，包括 K-12、高中、本科生、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联系。其他外展活动将与 PolarTREC、PolarPalooza 以及南极艺术家和作家（如果可能）协调进行。

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.