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

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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.