Collaborative Research: Geochemistry and Microbiology of the Extreme Aquatic Environment in Lake Vida, East Antarctica

Vida湖是麦克默多干谷中最大的湖泊，大约20米的冰层覆盖着未知深度的盐水，盐度至少是海水的7倍，全年温度低于-10摄氏度。从主要水体上方的冰中采集的盐水样本含有1)地球上任何天然水体中最高的氧化亚氮水平；2)异常的地球化学特征，包括异常高的氨和铁浓度；3)微生物数量高，超微生物比例异常（99%）。与其他干谷湖泊相比，这里的微生物群落也是独一无二的。本研究拟首次进入维达湖厚冰下的主要卤水体，进行现场测量，采集卤水柱样品，采集湖底沉积物岩心，进行详细的地球化学和微生物分析。这些结果将有助于描述湖中现在和过去的生命，评估现代和过去的沉积过程，并确定湖泊的历史。这项研究将由一个多学科团队进行，该团队将揭示与隔离了很长一段时间的非光合微生物群落相关的生物地球化学过程。本研究将探讨维达湖自然环境演化背景下的生物多样性、适应机制和进化过程。研究结果将通过出版物、在国家和国际会议上的介绍、冰下南极湖探测网站和麦克默多南极湖探测网站广泛传播。该研究将支持三名研究生和三名本科生研究助理。研究结果将被纳入伊利诺伊大学芝加哥分校（University of Illinois at Chicago）一门新的本科生生物地球科学课程，该课程的学生群体极其多样化，以少数族裔为主。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)Lake Vida is the largest lake of the McMurdo Dry Valleys, with an approximately 20 m ice cover overlaying a brine of unknown depth with at least 7 times seawater salinity and temperatures below -10 degrees C year-round. Samples of brine collected from ice above the main water body contain 1) the highest nitrous oxide levels of any natural water body on Earth, 2) unusual geochemistry including anomalously high ammonia and iron concentrations, 3) high microbial counts with an unusual proportion (99%) of ultramicrobacteria. The microbial community is unique even compared to other Dry Valley Lakes. The research proposes to enter, for the first time the main brine body below the thick ice of Lake Vida and perform in situ measurements, collect samples of the brine column, and collect sediment cores from the lake bottom for detailed geochemical and microbiological analyses. The results will allow the characterization of present and past life in the lake, assessment of modern and past sedimentary processes, and determination of the lake's history. The research will be conducted by a multidisciplinary team that will uncover the biogeochemical processes associated with a non-photosynthetic microbial community isolated for a significant period of time. This research will address diversity, adaptive mechanisms and evolutionary processes in the context of the physical evolution of the environment of Lake Vida. Results will be widely disseminated through publications, presentations at national and international meetings, through the Subglacial Antarctic Lake Exploration (SALE) web site and the McMurdo LTER web site. The research will support three graduate students and three undergraduate research assistants. The results will be incorporated into a new undergraduate biogeosciences course at the University of Illinois at Chicago which has an extremely diverse student body, dominated by minorities.