ORE-CZ: Riverine Biogeochemical Export From High-Latitude Catchments: The Role of Glaciers and Extreme Hydrologic Events

像阿拉斯加这样的北部地区目前变暖的速度是全球平均速度的两倍。这种变暖正在融化冰川，这会改变溪流中的水流，并可能引发被称为冰川下河流“暴发”的洪水事件。流经流域的水的方式的变化也对河流输送到海洋的水的质量产生了影响。该项目将评估变化的冰川如何影响从阿拉斯加海岸的分水岭到阿拉斯加湾近岸水域的溪水、营养物质和矿物的移动。项目人员将全年对有冰川的河流进行采样，并在大风暴和突发性洪水期间进行密集采样。该项目将提供有关气候变化将如何影响淡水和营养物质流入下游海洋环境中的食物网的关键信息。这一点很重要，因为阿拉斯加湾拥有地球上产量最高的海洋渔业之一。该项目还将为阿拉斯加东南大学的本科生提供技能和培训，为他们提供成为下一代地球科学家的机会。最后，项目负责人和学生将与位于朱诺的门登霍尔冰川游客中心密切合作，开发宣传材料，教育游客冰川变化对环境的影响。气候变化、极端事件和土地覆盖变化正在引发地球临界区的戏剧性变化。对集水区水文循环的干扰，如冰川融化，尤其重要，因为水参与了所有关键的区域进程。因此，了解流经流域的水流的时间和大小的变化及其对关键区域结构和过程的影响，如生物地球化学循环，是关键区域科学的核心。该项目将使用现场传感器和人工测量来量化经历快速冰川衰退的阿拉斯加东南部沿海分水岭的碳、氮、磷和汞的产量。极端水文事件，如大气河流和冰川湖暴发洪水，也将进行密集抽样，以评估它们对河流生物地球化学收支的影响。通过在一个前冰川湖的上方和下方进行采样，我们还将研究这些无处不在的冰川流域特征在调节沉积物和溶质下游流动方面所起的作用。来自阿拉斯加东南大学的本科生将参与该项目的所有方面，包括传感器部署、数据收集、实验室分析和项目结果的展示。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。

Northern regions like Alaska are currently warming twice as fast as the global average. This warming is melting glaciers, which changes the flow of water in streams and can trigger the onset of flood events known as “outbursts” in rivers beneath glaciers. Changes in the way that water flows through watersheds also has implications for the quality of water being transported by rivers to the ocean. This project will evaluate how changing glaciers influence the movement of streamwater, nutrients, and minerals from watersheds along the Alaskan coast to the nearshore waters in the Gulf of Alaska. Project personnel will sample rivers with glaciers throughout the year and intensively during large storms and “outburst” floods. The project will provide critical information about how climate change will impact the flow of freshwater and nutrients into food webs in downstream marine environments. This is important because the Gulf of Alaska contains one of the most productive marine fisheries on Earth. The project will also provide skills and training for undergraduate students at the University of Alaska Southeast, providing them the opportunity to become the next generation of earth scientists. Finally, project leaders and students will work closely with the Mendenhall Glacier Visitor Center in Juneau to develop outreach materials for educating visitors about the environmental impacts of glacier change.Climate change, extreme events, and land-cover transformation are triggering dramatic changes to the Earth’s critical zone. Disturbances to the catchment hydrologic cycle, such as the melting of glaciers, are particularly consequential because water is involved in all critical zone processes. Therefore, understanding changes to the timing and magnitude of water flow through catchments and its influence on critical zone structure and processes, such as biogeochemical cycling, is central to critical zone science. This project will use in-situ sensors and manual measurements to quantify yields of carbon, nitrogen, and phosphorus as well as mercury in coastal watersheds of southeast Alaska experiencing rapid glacier recession. Extreme hydrologic events, such as atmospheric rivers and glacial lake outburst floods will also be sampled intensively to evaluate their impacts on riverine biogeochemical budgets. By sampling above and below a pro-glacial lake, we will also examine the role that these ubiquitous features of glacier watersheds play in modulating downstream flows of sediments and solutes. Undergraduate students from the University of Alaska Southeast will be involved in all aspects of the project including sensor deployment, data collection, laboratory analysis, and presentation of project results.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.