NSFGEO-NERC:Collaborative Research: Chemistry and Biology under Low Flow Hydrologic Conditions Beneath the Greenland Ice Sheet Revealed through Naturally Emerging Subglacial Water

NSFGEO-NERC：合作研究：通过自然涌出的冰下水揭示格陵兰冰盖下方低流量水文条件下的化学和生物学

• 批准号: 2039582
• 负责人: Trinity Hamilton
• 金额: $ 27.49万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2039582&HistoricalAwards=false
• 关键词: NSFGEO; NERC; Collaborative; Research; Chemistry

This project is jointly funded by the National Science Foundation’s Directorate of Geosciences (NSF/GEO) and the National Environment Research Council (UKRI/NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award, each Agency funds the proportion of the budget and the investigators associated with its own component of the work.Weathering is an important process that releases nutrients that are essential for life from rocks and minerals in the Earth’s surface. This project seeks to understand the effect of large glaciers on weathering processes beneath the Greenland Ice Sheet and the consequences for life. During summer, nutrients and other products are flushed out of the Greenland Ice Sheet with water from melting ice. While these products have been sampled in spring and summer, it is not known how weathering processes are different during winter. In this project, researchers will sample the seasonal ice that forms in front of two of Greenland’s glacial outlets, Isunnguata Sermia and Leverett Glacier, during the freezing months to assess the chemistry and microbiology processes that reflect wintertime conditions beneath the ice sheet – periods when input of fresh meltwater is minimal. These samples will increase knowledge of winter conditions under the Greenland Ice Sheet and help better understand the interior portions of the ice sheet which are largely inaccessible. Such information will help in assessing past conditions, when colder atmospheric conditions resulted in minimal meltwater input through the ice sheet and to the glacial bed. These analyses will inform understanding of the role of glaciers on earth’s nutrient cycles presently, under past ice age conditions, and in a future deglaciating world.The Greenland Ice Sheet is a major exporter of biologically important elements to the world’s oceans. However, most of our knowledge of chemical and biological fluxes from the ice sheet comes from the summer outflux of outlet glaciers whose channelized waters contact only a limited portion of the glacier bed. The majority of the glacier-bed interface contains slow-flowing, distributed waters not representative of this flux. The project will test the hypothesis that overwinter chemical and biological processes under outlets of the Greenland Ice Sheet differ substantially from summer outflow and represent a window into widespread, but typically inaccessible, distributed flow. The principal sample collection method will be early spring coring of naled ice that forms at glacial termini from wintertime subglacial flow. Chemical, mineralogical, and biological constituents of this flow will be compared to material emerging from the initial, peak, and terminal phases of the melt season. Elsewhere in the Arctic, the chemistry of frozen overwinter subglacial material shows significant limitation in oxygen or sediment supply compared with even the first spring melt, supporting the idea that naled ice reveals a unique overwinter system. The naled ice and outflow of Isunnguata Sermia and Leverett Glacier will be sampled over two years. These West Greenland outlets differ by more than an order of magnitude in the size of the catchments they drain, thereby testing the effect of scale on biogeochemistry. Naled ice structure will be characterized by ground penetrating radar and ice borehole temperature profiles. The aqueous geochemistry, stable isotopes of carbonate and sulphate, and mineralogy of the suspended sediment of ice and water will be assessed. These analyses will document changes in the mineral flux and supply of atmospheric gases at the glacial bed between winter low flow conditions and peak summer melt. Microbial abundance, diversity, metagenomics, and stable isotopes of biomass will also be measured to understand the concomitant relationship between geochemical conditions and biological communities. Researchers will incorporate findings into a number of outreach efforts including developing a new curriculum module for the Center for Earth and Environmental Sciences, providing research opportunities for underrepresented students as part of the Bridge to Research Program and preparing hands-on activities for the Market Science Program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目由美国国家科学基金会地球科学理事会 (NSF/GEO) 和英国国家环境研究委员会 (UKRI/NERC) 通过 NSF/GEO-NERC 牵头机构协议共同资助。单一的美国/英国联合提案将由其研究人员拥有最大预算比例的机构提交并进行同行评审。在成功联合确定资助后，每个机构将资助与其相关的预算和研究人员的比例。的组成部分风化是从地球表面的岩石和矿物质中释放生命必需的营养物质的重要过程，该项目旨在了解大型冰川对格陵兰冰盖下的风化过程的影响以及夏季对生命的影响。 、营养物质和其他产物被融化的冰水从格陵兰冰盖中冲走，虽然这些产物在春季和夏季进行了采样，但尚不清楚冬季的风化过程有何不同。季节性的在冰冻月份期间，格陵兰岛的两个冰川出口（伊桑瓜塔塞尔米亚和莱弗里特冰川）前形成的冰，以评估反映冰盖下方冬季条件的化学和微生物学过程，这些样本将在冰盖下方的冬季条件下进行。增加对格陵兰冰盖下冬季条件的了解，并帮助更好地了解基本上无法进入的冰盖内部部分，这些信息将有助于评估过去的条件，因为较冷的大气条件导致了最小的影响。这些分析将有助于了解冰川在当前、过去的冰河时代条件下以及未来冰川消融的世界中对地球营养循环的作用。然而，我们对冰盖化学和生物通量的大部分了解来自于夏季流出的冰川，其渠道化水域仅与有限的部分接触。冰川床界面的大部分包含缓慢流动的分布式水，不能代表这种通量。该项目将验证格陵兰冰盖出口处的越冬化学和生物过程与夏季流出物有很大不同的假设。代表了一个了解广泛但通常难以接近的分布式流动的窗口，主要的样本采集方法将是在冬季冰下流动的冰河末端形成的冰芯。将流量与北极其他地方融化季节的初始、高峰和末期出现的物质进行比较，与第一次春季融化相比，冬季冰下物质的化学成分显示出氧气或沉积物供应的显着限制，这支持了这一点。纳拉德冰揭示了独特的越冬系统，我们将在两年内对伊桑瓜塔塞尔米亚和莱弗里特冰川的纳拉德冰和流出物进行采样，这些冰点的差异超过一个数量级。其排水的集水区的大小，从而测试水垢对生物地球化学的影响，将通过探地雷达和冰钻孔温度剖面来表征，碳酸盐和硫酸盐的稳定同位素以及悬浮沉积物的矿物学。将评估冰和水的变化。这些分析将记录冬季低流量条件和夏季微生物丰度高峰之间冰川床的矿物质通量和大气气体供应的变化。研究人员还将测量生物量的多样性、宏基因组学和稳定同位素，以了解地球化学条件和生物群落之间的伴随关系。研究人员将把研究结果纳入许多外展工作中，包括为地球与环境科学中心开发一个新的课程模块，作为研究桥梁计划的一部分，为代表性不足的学生提供研究机会，并为市场科学计划准备实践活动。该奖项反映了 NSF 的法定使命，并通过利用基金会的智力优势和更广泛的评估进行评估，认为值得支持影响审查标准。