Impacts of Climate Change and Melting Glaciers on Coastal Ecosystems in the Gulf of Alaska

As glaciers melt from climate change, their contents – namely, large quantities of freshwater, sediment, and nutrients – are slowly released into coastal ecosystems. This project addressed the impacts of melting glaciers on coastal ecosystems in the Copper River region of the Gulf of Alaska, which is home to several commercially important fisheries. Researchers examined how glacial melting is altering the amount and timing of freshwater that enters the Gulf of Alaska from the Copper River. They also investigated the source and amount of two nutrients, iron and nitrate, dissolved in the water. As a complementary piece of the study, researchers tested the relationship between nutrient levels, plankton populations, and the populations of fish that feed on plankton.



Results show that substantial quantities of nutrients (e.g., up to hundreds of tons of iron) from glacial sediment are being added to the Copper River environment each year. Climate change, through accelerated glacial melting, may increase the quantity of nutrient additions to coastal ecosystems. Such changes would likely produce ecosystem changes – as high nutrient levels correspond with increased vegetation – but it is unknown what the exact changes would look like. One of the products of this research that may prove especially useful to natural resource managers is a model that shows how the present-day coastal ecosystem responds to seasonal changes in nutrient inputs as well as predictions about future ecosystem change in response to glacial melting in the coming decades.