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

冰川融化的水在冰川的顶部、中间和下面流动，最终流入湖泊或海洋。有时，这些水不会直接流向海岸，而是首先进入冰川旁边的近岸湖泊，这些湖泊被称为冰缘湖，可以用冰筑坝。当这些湖中的冰坝蓄水失败时，水会在几天内迅速流到海岸。格陵兰岛最大的冰缘湖被认为是蒂尼利克湖，该湖最近于2021年流入海洋。目前的低水位意味着湖中的沉积物现在暴露出来了。这将是第一个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。它还将确定湖泊储存如何改变冰川融水的化学成分。随着气候持续变暖，冰缘湖泊的储水量预计会增加，确定Tininnilik湖的化学成分对了解沿海海洋排水后的生态系统变化和碳循环具有重要意义。项目领导包括三名女性，她们都是少数民族和种族。作为这个项目的一部分，将创建一个基于网络的虚拟现实Tininnilik湖之旅，供任何人使用。这次参观对其他试图更好地了解湖泊布局的科学家来说很重要，也将成为公众的教学工具。由于冰原下的侵蚀和风化作用，冰下水域富含宏观和微观营养物质。这些富含营养的水可以直接排入海洋或储存在前冰川湖泊中，包括冰缘湖泊。Tininnilik湖是格陵兰岛西部Sarqardliup冰川沿线的一座冰坝所限制的大型冰缘湖。它大约每10年排入一个当地的峡湾，最近一次是在2021年，暴露了以前被淹没的沉积物。2021年排水之前的初步工作表明，铁（海洋浮游植物的重要微量营养物质）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，铁浓度也自相矛盾地高。该项目将收集和分析来自Tininnilik湖不同叶的水样和暴露的沉积物，以解决冰边缘湖泊如何改变近岸和开放海洋生态系统的化学和微生物组成以及营养物质的可用性。Sarqardleq峡湾，Tininnilik湖的排水口，是当地土著居民重要的鱼类来源，这项工作将有助于未来的研究，以了解快速排水事件如何影响海洋食物网。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.