Permafrost thaw is occurring across the Arctic with potential consequences for hydrology, ecosystems, humans, and wildlife. A team of scientists from the U.S. Geological Survey Alaska Science Center, the National Park Service, and the Department of Energy Oak Ridge National Laboratory are collaborating to understand the impacts of warming on the ecosystems in the Noatak Preserve in Alaska.
In a recent study, scientists monitored temperature across 11 headwater streams in Noatak National Preserve in northwest Alaska. They used groundwater-heat flow modeling and stream temperature data to demonstrate how permafrost presence and thaw impacts water temperatures in headwater streams. A new publication Permafrost promotes shallow groundwater flow and warmer headwater streams illustrates that permafrost leads to warmer streams by restricting subsurface flow to shallow soils that can be warmed by incoming solar radiation. Headwater streams are more susceptible to hydrologic changes than larger rivers, control the flux of solutes and nutrients from the land to rivers and the ocean, and provide critical habitat and food resources to juvenile fish. This work is relevant to predicting changes in riverine ecosystems across the Arctic and will directly inform the National Park Service in managing the Arctic Network Parks.