ACRC Director Jason Fellman collects water samples at the Mendenhall Glacier outflow.

Mendenhall Glacial Outflow Sampling

ACRC researchers are sampling the glacial outflow stream during large storms and the Mendenhall outburst flood to better understand how climate change and extreme events are impacting coastal watersheds.

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, mercury, and carbon from watersheds along the Alaskan coast to the nearshore waters in the Gulf of Alaska. The team will sample rivers with glaciers throughout the year and intensively during large storms and the “outburst” flood from the Mendenhall Glacier. 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 in the Gulf of Alaska, which contains one of the most productive marine fisheries on Earth. 

Using in-situ sensors and manual stream measurements, the research team will assess the amount of carbon, nitrogen, phosphorus, sediment, and mercury in coastal watersheds of southeast Alaska experiencing rapid glacier recession. Extreme hydrologic events, such as atmospheric rivers and glacial lake outburst floods will be sampled intensively to evaluate their impacts on annual 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.

Image: Loading a kayak with the instruments and equipment needed monitor and sample the Mendenhall Glacier outflow before the paddle commute accross Mendenhall lake.