Collaborative Research: RAPID: Biogeochemistry of water and sediments from a recently drained Greenland ice-marginal lake

从冰川融化的水在冰川上方、冰川上方和冰川下方流动，最终流入湖泊或海洋。有时，这些水并不直接进入海岸，而是首先进入冰川旁边的近岸湖泊，称为冰缘湖泊，这些湖泊可以被冰筑坝。当这些湖泊中蓄水的冰坝坍塌时，水可以在几天内迅速排到海岸。格陵兰最大的冰缘湖泊据信是廷尼利克湖，该湖最近于2021年排入海洋。目前的低水位意味着湖中的沉积物现在暴露了出来。这将是第一次测量湖泊和沉积物中的化学物质、营养物质和微生物的研究。它还将决定湖泊储存如何改变从冰川融化的水的化学成分。随着气候的持续变暖，冰缘湖泊中储存的水量预计将增加，确定蒂尼尼利克湖的化学成分对于了解排水后沿海海洋的生态系统变化和碳循环非常重要。该项目的领导人包括三名妇女，她们都是少数民族和少数族裔。作为该项目的一部分，将创建一个基于网络的廷尼利克湖虚拟现实旅游，供任何人使用。对于其他试图更好地了解湖泊布局的科学家来说，这次参观将是重要的，也将是公众的教学工具。由于冰盖下的侵蚀和风化，冰下水域富含宏观和微观营养物质。这些营养丰富的水可以直接排放到海洋中，也可以储存在前冰川湖泊中，包括冰缘湖泊。Tininnilik湖是格陵兰西部Sarqardliup冰川沿线的一个大型冰缘湖泊，受到冰坝的限制。它大约每隔10年就会排入当地的峡湾，最近一次是在2021年，暴露出以前被淹没的沉积物。2021年排水前的初步工作表明，铁(海洋浮游植物的一种重要的次要营养物质)比直接进入海洋的冰川融水大10到100倍。与其他氧化还原敏感元素浓度相比，铁的浓度也高得离谱。该项目将收集和分析Tininnilik湖不同湖瓣的水样和裸露的沉积物，以研究冰缘湖泊如何改变近岸和开阔海洋生态系统的化学和微生物组成以及营养物质的有效性。Tininnilik湖汇入的Sarqardleq峡湾是当地土著居民的重要鱼类来源，这项工作将有助于未来寻求了解快速排水事件如何影响海洋食物网的研究。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Water melting from glaciers flow on top of, through, and underneath glaciers, ultimately ending up in lakes or the ocean. Sometimes, this water does not take a direct path to the coast, but first enters near-shore lakes next to the glacier, called ice-marginal lakes, which can be dammed by ice. When the ice dams holding the water in these lakes fail, the water can rapidly drain to the coast over several days. The largest ice-marginal lake in Greenland is believed to be Lake Tininnilik, which recently drained into the ocean in 2021. The current low water levels mean that sediments in the lake are now exposed. This will be the first study to measure chemicals, nutrients, and microorganisms in the lake and sediments. It will also determine how lake storage changes the chemistry of water melting from the glacier. With continued climate warming, the amount of water stored in ice-marginal lakes is expected to increase, and determining the chemistry of Lake Tininnilik is important for understanding ecosystem change and carbon cycling in the coastal ocean following drainage. The project leadership includes three women, all of which are ethnic and racial minorities. As part of this project, a web-based virtual reality tour of Lake Tininnilik will be created for anyone to use. The tour will be important for other scientists trying to better understand the layout of the lake and will also be a teaching tool for the public. Because of erosion and weathering under ice sheets, subglacial waters are rich in macro- and micro-nutrients. These nutrient-rich waters can be directly discharged into the ocean or stored in pro-glacial lakes, including ice-marginal lakes. Lake Tininnilik is a large ice-marginal lake restrained by an ice dam along Sarqardliup Glacier in western Greenland. It drains approximately every 10 years into a local fjord, most recently in 2021, exposing previously inundated sediments. Preliminary work prior to the 2021 drainage shows that iron (an important minor nutrient for marine phytoplankton) is 10 to 100 times greater than glacial meltwater entering the ocean directly. The iron concentrations are also paradoxically high compared to other redox sensitive element concentrations. This project will collect and analyze water samples from different lobes of Lake Tininnilik and exposed sediments to address how ice-marginal lakes change the chemical and microbial composition and availability of nutrients for near-shore and open-ocean ecosystems. Sarqardleq Fjord, into which Lake Tininnilik drains, is an important source of fish for local indigenous populations, and this work will aid future studies seeking to understand how rapid drainage events may affect the marine food web.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.