Cryptic Hydrology of the McMurdo Dry Valleys: Water Track Contributions to Water and Geochemical Budgets in Taylor Valley, Antarctica

麦克默多干谷的隐秘水文学：水道对南极洲泰勒谷水和地球化学预算的贡献

• 批准号: 1343649
• 负责人: Joseph Levy
• 金额: $ 32.8万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1343649&HistoricalAwards=false
• 关键词: Cryptic; Hydrology; McMurdo; Dry; Valleys

Intellectual Merit: The PIs propose to quantify the hillslope water, solute, and carbon budgets for Taylor Valley in the McMurdo Dry Valleys, using water tracks to investigate near-surface geological processes and challenge the paradigm that shallow groundwater is minimal or non-exixtant. Water tracks are linear zones of high soil moisture that route shallow groundwater downslope in permafrost dominated soils. Four hypotheses will be tested: 1) water tracks are important pathways for water and solute transport; 2) water tracks transport more dissolved silica than streams in Taylor Valley indicating they are the primary site of chemical weathering for cold desert soils and bedrock; 3) water tracks that drain highland terrains are dominated by humidity-separated brines while water tracks that drain lowland terrains are dominated by marine aerosols; 4) water tracks are the sites of the highest terrestrial soil carbon concentrations and the strongest CO2 fluxes in Taylor Valley and their carbon content increases with soil age, while carbon flux decreases with age. To test these hypotheses the PIs will carry out a suite of field measurements supported by modeling and remote sensing. They will install shallow permafrost wells in water tracks that span the range of geological, climatological, and topographic conditions in Taylor Valley. Multifrequency electromagnetic induction sounding of the upper ~1 m of the permafrost will create the first comprehensive map of soil moisture in Taylor Valley, and will permit direct quantification of water track discharge across the valley. The carbon contents of water track soils will be measured and linked to global carbon dynamics.Broader impacts: Non-science majors at Oregon State University will be integrated into the proposed research through a new Global Environmental Change course focusing on the scientific method in Antarctica. Three undergraduate students, members of underrepresented minorities, will be entrained in the research, will contribute to all aspects of field and laboratory science, and will present results at national meetings.

智力优点：PI建议量化麦克默多干谷泰勒谷的山坡水、溶质和碳预算，利用水迹研究近地表地质过程，并挑战浅层地下水极少或不存在的范例。水径是高土壤湿度的线性区域，在以永久冻土为主的土壤中沿着斜坡引导浅层地下水。将测试四个假设：1）水迹是水和溶质运输的重要途径； 2）泰勒谷的水道比溪流运输更多的溶解二氧化硅，表明它们是寒冷沙漠土壤和基岩化学风化的主要场所； 3）排出高地地形的水道主要是湿度分离的盐水，而排出低地地形的水道主要是海洋气溶胶； 4）水径是泰勒谷陆地土壤碳浓度最高和CO2通量最强的部位，其碳含量随着土壤年龄的增长而增加，而碳通量则随着年龄的增长而减少。为了测试这些假设，PI 将进行一系列由建模和遥感支持的现场测量。他们将在横跨泰勒谷地质、气候和地形条件范围的水道中安装浅层永久冻土井。对永久冻土层上部约 1 m 的多频电磁感应探测将创建泰勒谷的第一个土壤湿度综合图，并将允许直接量化整个山谷的水径排放。水道土壤的碳含量将被测量并与全球碳动态联系起来。更广泛的影响：俄勒冈州立大学的非科学专业学生将通过一门新的全球环境变化课程纳入拟议的研究，该课程重点关注南极洲的科学方法。三名本科生是代表性不足的少数族裔，他们将参与这项研究，为现场和实验室科学的各个方面做出贡献，并将在全国会议上展示成果。