The Arctic is one of the world’s most challenging environments, characterized by extreme cold, months of darkness, and a landscape that shifts dramatically between solid sea ice and open water. Sustaining life requires highly specialized food systems that maximize limited energy resources. The organisms that thrive here have evolved complex strategies to efficiently capture, store, and utilize energy.
The Foundation of the Arctic Food Web
The base of the Arctic food web is primarily marine and is driven by the seasonal dynamics of sunlight and sea ice. Primary production begins with ice algae, which grow in the brine channels and underside of the sea ice when light penetration increases in early spring. These algae are able to bloom earlier than open-water organisms, providing a crucial, lipid-rich food source for grazers well before the major summer bloom of phytoplankton.
As the sea ice melts and retreats in the summer, the influx of sunlight and nutrients triggers a bloom of phytoplankton in the open water. These microscopic plants, particularly large diatoms, become the dominant energy source, fueling the next trophic level of zooplankton. Arctic copepods, such as Calanus glacialis, are the most important zooplankton, linking primary producers and larger animals. These copepods accumulate energy-dense lipids, transferring this concentrated energy up the food chain to fish and marine mammals.
Key Animal and Plant Food Resources
In the ocean, ringed seals and bearded seals are primary prey for top predators. They also feed on Arctic cod, which is a central part of the marine food web. Larger marine mammals, such as bowhead and beluga whales, filter-feed on dense swarms of zooplankton and small schooling fish. Fish species like Arctic char and cod are significant food resources for seabirds and humans.
On the land, food resources are far more scarce, as the tundra supports a smaller variety of large herbivores. Caribou and muskox are the largest terrestrial food sources, subsisting on grasses, sedges, and lichen, especially during the brief summer. Birds like the Svalbard rock ptarmigan are also consumed. Tundra vegetation is limited, consisting mostly of low-lying plants, mosses, lichens, and berries, which are gathered during the short growing season.
Nutritional Adaptations for Survival
Survival in a cold, food-scarce environment demands specialized physiological mechanisms to maximize energy intake and retention. A major adaptation is the ability to deposit and use stores of body fat for insulation and energy reserves. For many marine mammals, this fat is stored as blubber, a specialized adipose tissue that provides both buoyancy and highly effective thermal insulation.
Animals like the polar bear have genetic adaptations that allow them to process a high-fat diet—up to 50% of their body weight can be fat—without developing the cardiovascular issues seen in humans. Genetic changes enable them to efficiently manage high blood lipid levels. Similarly, terrestrial species, such as the Svalbard rock ptarmigan, can accumulate fat reserves that account for up to 30% of their total body mass before winter. These physiological mechanisms, including countercurrent heat exchange in extremities, collectively minimize heat loss and maximize the caloric yield from their food.
The Human Arctic Diet and Modern Concerns
The traditional diet of the Indigenous populations of the Arctic is characterized by its high content of fat and protein from marine and terrestrial mammals, often referred to as “country food.” This diet provided a dense source of nutrients unavailable in the plant-scarce environment. Marine-based foods, particularly seal and whale blubber, are rich in Omega-3 fatty acids and Vitamin D, which is difficult to obtain from sunlight during the dark winter months.
This traditional food system faces threats from environmental contamination and climate change. Persistent organic pollutants (POPs) and heavy metals, such as mercury, are transported to the Arctic from industrial regions and bioaccumulate in the food web. Because humans consume animals at the top of this chain, they are exposed to elevated levels of these contaminants. Climate change further complicates food security by altering animal migration patterns and reducing the viability of hunting grounds, such as the thinning of sea ice. The warming of the Arctic also causes permafrost to thaw, leading to the spoilage of traditional fermented foods and increasing risks associated with safe food preparation and storage.