Marine Ecosystems

Science Center Objects

The USGS conducts research on marine wildlife, habitats, and processes to provide science to inform our partners as they make decisions relative to species status, resource use, and human activities.

Return to Ecosystems

Polar Bears

Polar bear mother and two cubs on the Beaufort Sea ice.

Polar bear mother and two cubs on the Beaufort Sea ice. (Credit: Steven Amstrup, USGS, Alaska Science Center. Public domain.)

The long-term persistence of polar bears is linked to the health of the Arctic marine ecosystem, particularly the availability of sea ice habitat (read more here). The USGS polar bear research program addresses changes in sea ice and other factors that may influence the long-term persistence of polar bears in the Southern Beaufort Sea of northern Alaska and across the circumpolar Arctic.

Nearshore Marine Ecosystems

Nearshore systems are the habitats in which most people interact with marine environments, and they have high economic, recreational, and ecological values. Nearshore ecosystems include eelgrass and seaweeds, benthic invertebrate and fish, and a unique group of top predators, including sea otters. USGS research addresses natural and human-induced changes to this ecosystem and all its components.

Pacific walrus hauled out on ice

Pacific walrus hauled out on ice. Middle walrus has satellite tag implanted in back. (Public domain.)


The Pacific walrus ranges throughout much of the Chukchi and Bering seas. Walruses rely on sea ice as a platform to rest upon. Walruses forage on the seafloor for a wide range of invertebrates (primarily clams and marine worms). Arctic sea ice is rapidly decreasing and causing shifts in prey and changes to walrus distributions and activity budgets. USGS research is determining the possible consequences to the walrus population from declines in Arctic sea ice and other changes to northern marine ecosystems.

Seabirds and Forage Fish Ecology

A Tufted Puffin is flying near it's colony on Bogoslof Island

A Tufted Puffin is flying near its colony on Bogoslof Island (volcano) in the Aleutian Islands. (Credit: Ajay Varma, USGS. Public domain.)

Alaska's coastal and offshore waters provide foraging habitat for an estimated 100 million birds of more than 90 different species. All of these birds depend on the sea to provide a wide variety of food types including krill, forage fish, and squid. Seabird populations are also affected by human activities that have direct impacts (pollution, bycatch in fishing gear) and indirect effects (global warming alters food availability) on birds. USGS research is quantifying how variability in marine environments regulates seabird food supplies, seabird foraging success and population dynamics. 

Habitat Dynamics

Each year the Arctic landscape transitions from a dark and frigid winter to a highly productive summer. Wildlife species synchronize their migrations and reproductive cycles to capitalize on the flourishing habitat conditions that accompany long summer days. However, natural weather variability as well as climate warming can influence the availability and quality of habitats during key stages of migration and reproduction. USGS research uses satellite imagery and weather data to quantify the dynamics of habitat conditions across the Arctic and help improve our understanding of how weather and seasonality can affect wildlife movements and population fluctuations.

Ecosystems Analytics

The Ecosystems Analytics group uses novel and cutting edge statistical, mapping, and graphical methods to conduct research on a variety of taxa. Our overarching goal is to help inform wildlife and land management decisions through assisting partners with designing monitoring programs, analyzing existing data, and developing new research projects. Our focus often involves modeling wildlife population dynamics through space and time and predicting how populations may respond to ecological and anthropogenic changes in the future.


The Arctic ecosystem is rapidly changing and numerous wildlife species and their habitats are responding to these changes.  USGS research quantifies the responses (positive, negative, and stable) of wildlife species and their habitats to ecosystem change in the Arctic and makes information on these responses available to inform management decisions related to development of oil and gas resources, sport and subsistence harvest, and population trends of northern latitude wildlife populations.