Collaborative Research: Straight to the Source- Mineral Weathering in Snowbanks and Supraglacial Ice, McMurdo Dry Valleys, Antarctica

合作研究：直奔源头——南极洲麦克默多干谷雪堆和冰上冰的矿物风化

• 批准号: 2148066
• 负责人: Anna Bergstrom
• 金额: $ 26.04万
• 依托单位: Boise State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2148066&HistoricalAwards=false
• 关键词: Collaborative; Research; Straight; Source; Mineral

Glacial erosion produces large quantities of sediment that can change the chemistry of surrounding land and ocean ecosystems. While the nutrients underneath glaciers are known to be important for nearby biological communities, comparatively less is known about the chemistry and importance of glacier surfaces and snowpack, which can trap dust - small particles of rock that are deposited by wind and with snowfall. The dust is darker than ice and snow and therefore can warm during sunny periods and melt the surrounding frozen water, generating small amounts of liquid water. During cloudy and cold periods, solar radiation can no longer heat the particles and the liquid water around the dust freezes again. These thawing and freezing cycles can break down the dust and release nutrients, such as iron, which can potentially be used by organisms in the ice or can be transported to streams, lakes, and/or the ocean during periods of high melt. This research will combine computer modeling and laboratory experiments to understand 1) what happens (chemically and physically) to glacier and snowpack dust during freezing and thawing and 2) how to model freezing and thawing of water and dust in glacier ice. Two traveling exhibits exploring the connections between science and art will result from this project, allowing for diverse audiences to connect with the Antarctic continent and understand how small-scale science influences large-scale systems. The results of this study will determine the geochemistry of glacial meltwater due to freezing and thawing, and whether the meltwater contains critical nutrients for surrounding ecosystems.Despite low temperatures and the relative scarcity of liquid water, glacial systems can be a major source of trace metals, nutrients and other weathering products to proglacial and marine systems. While the importance of weathering has been established in subglacial and proglacial environments, less is understood about weathering mechanisms or the composition of major and trace nutrients at the most upstream source: within snow and supraglacial ice. Wind deposits fine-grained sediment on ice surfaces, which can then melt or become incorporated into the ice profile and experience a range of thermal regimes and freeze-thaw conditions. Daily freeze-thaw cycling drives physical and chemical weathering of sediment grains, yet few studies have explicitly examined the frequency and intensity of freeze-thaw cycles and how they control major ion and trace metal release, alteration, and mobility. This interdisciplinary study will use geochemical and energy balance modeling, freeze-thaw experimentation, and scanning electron microscopy to advance knowledge of mineral weathering in ice and snow active layers. Existing samples collected from the McMurdo Dry Valleys of Antarctica, an ecosystem that relies on runoff derived from supraglacial ice and snow melt, will be utilized. Two traveling exhibits exploring the connections between science and art will result from this project, the first focused on connecting the macro-scale Antarctic continent to micro-scale microscopy images, and the second a contemporary art exhibit that will explore the Antarctic continent and our perceptions of scale. Findings from this research will contribute to knowledge of nutrient bioavailability and delivery to proglacial environments and polar oceans, watershed-scale weathering in glacial systems, and the conditions that create microsites for life on glaciers and other icy systems.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.

冰川侵蚀会产生大量的沉积物，可以改变周围的土地和海洋生态系统的化学反应。虽然已知冰川下面的营养对于附近的生物群落很重要，但对冰川表面和积雪的化学和重要性的了解相对较少，这些冰川表面和积雪的重要性可能会捕获灰尘 - 岩石的小岩石，这些岩石是由风和降雪降落的。灰尘比冰雪更暗，因此可以在阳光明媚的时期温暖，并在周围的冷冻水中融化，从而产生少量的液态水。在多云和寒冷的时期，太阳辐射无法再加热颗粒，尘埃周围的液态水再次冻结。这些解冻和冷冻周期可以分解灰尘和释放养分，例如铁，在高熔体期间，有机体可能会被冰中的生物使用或可以将其运输到溪流，湖泊和/或海洋。这项研究将结合计算机建模和实验室实验，以了解1）在冷冻和解冻过程中（化学和物理上）（物理和物理上）将发生什么（从化学上和物理上）到冰川和雪堆灰尘，以及2）如何模拟冰川冰中的水和灰尘的冻结和解冻。两个探索科学与艺术之间联系的旅行展览将由该项目引起，从而使不同的受众与南极大陆建立联系，并了解小规模的科学如何影响大型系统。这项研究的结果将确定由于冷冻和解冻而导致的冰川融化的地球化学，以及融合水是否含有周围生态系统的关键营养素。尽管如此，低温和液体水的相对稀缺，冰川系统可以是痕量金属，营养素，营养和其他产品的主要来源。虽然在冰河和冰期环境中已经确定了风化的重要性，但在最上游来源的风化机理或主要营养素的组成或痕量营养​​素的组成方面却较少了解：在雪和冰期冰内。风沉积在冰面上细粒沉积物，然后可以融化或融合到冰曲线中，并体验一系列的热度和冻融条件。每日冻结循环驱动沉积物晶粒的物理和化学风化，但很少有研究明确检查了冻融周期的频率和强度，以及它们如何控制主要离子和痕量金属释放，变化和迁移率。这项跨学科研究将使用地球化学和能量平衡建模，冻结实验以及扫描电子显微镜来提高对冰与雪活动层中矿物风化的了解。将利用从南极洲的McMurdo干谷收集的现有样品，这是一个依赖于冰冰与雪融化的径流的生态系统。两个探索科学与艺术之间的联系的旅行展览将由该项目引起，第一个重点是将宏观尺度的南极大陆连接到微观显微镜图像，第二次是当代艺术展览，将探索南极大陆和我们对规模的看法。这项研究的发现将有助于了解营养素的生物利用度以及向冰期环境和极地海洋的交付，流域尺度的风化，以及在冰川和其他冰冷系统上创造生命的微地铁的条件。该奖项通过评估了NSF的法定任务，并通过评估了构成的知识群体，这些奖项反映了对构成的构成构成和众所周知的影响。