EAR-Climate: Acquisition of hydrometric equipment to support undergraduate training and research on glacier lake outburst floods in southeast Alaska

University Of Alaska Southeast Juneau Campus, Juneau AK

Investigators

Abstract

As glaciers melt each summer and recede over the years due to the warming climate, the chemical nature of their meltwater changes. Studying the physical and chemical characteristics of the meltwater released from glaciers is important because it directly affects the quality of downstream lakes, streams, and coastal marine zones. The Coastal Mountains of southeast Alaska are experiencing some of the highest glacial melt rates on Earth. As the glaciers shrink, they leave behind newly formed landscapes and waterbodies such as lakes collecting water in front of the glacier (proglacial lakes) and lakes on the edges of glaciers that are dammed by the glacier ice (glacially dammed lakes). Such lakes can trap sediment, nutrients, carbon, and other elements, preventing them from moving downstream. Additionally, glacially dammed lakes can suddenly release massive outbursts of water if their ice dam fails, creating flooding hazards and sending a surge of sediment and dissolved chemicals downstream. With thousands of glaciers currently receding in Alaska, it is critical to characterize and quantify the ongoing changes in glacierized watersheds and to better understand their ecological impacts. We will track the quantity and quality of water and sediment moving through and out of a glacially dammed lake and a proglacial lake in southeast Alaska using the acoustic doppler velocimeter and other equipment acquired through this project. In doing so, we will involve and train undergraduate students from the University of Alaska Southeast and the local high school, helping to equip the next generation of earth scientists with the skills and tools they need to address glacier change, hydrologic dynamics, Earth surface processes, and natural hazards. Climate change has triggered glaciers in the Coastal Mountain of Alaska to recede at some of the highest rates on Earth. Increased glacier mass loss is causing the growth of (1) proglacial lakes that can dramatically alter sediment and chemical export from watersheds and of (2) glacially-dammed lakes, which can produce hazardous glacial lake outburst floods (GLOFs) and release a large pulse of biogeochemical elements and sediment to downstream ecosystems. Understanding the storage and release of carbon, water, sediment, and metals such as mercury in and through these glacier-associated lakes is important for explaining how glacier retreat and ensuing landscape change will affect current and future chemical and sediment fluxes. As warming continues and glaciers further diminish, the changing physical and chemical outputs from glaciated watersheds will have implications for recipient aquatic ecosystems, including food web structure and productivity, availability of contaminants, organic carbon burial in coastal sediments, CO2 outgassing to the atmosphere, and the seasonal timing and intensity of coastal ocean acidification. In this project, we will monitor the hydrometric impacts of glacial change in southeast Alaska by acquiring an Accoustic Doppler Velocity meter, water quality sondes, and a multi-probe water quality meter for use in the glacierized Mendenhall watershed in Juneau, Alaska. The hydrometric instruments will be used to train undergraduate students through class labs and research assistantships at the University of Alaska Southeast, which is a small, Alaska-native serving, undergraduate university, and to engage local high school students. The instruments will allow us to further develop a research program aimed at understanding the dynamics and consequences of glacier melt and GLOFs on sediment and chemical export to the highly productive coastal watersheds of southeast Alaska. 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.