Sea-Faring Polar Bears Ingesting More Pollutants Than Bears on Land

(CN) – The feeding habits of polar bears are being thrown for a loop because of melting sea ice, causing some to feed on prey with higher concentrations of pollutants.

The alarming trend is the focus of a study published Wednesday that breaks down how Barents Sea polar bears are being affected by climate change.

Researcher Pierre Blévin at the Norwegian Polar Institute found that polar bears hunt for prey in two unique categories.

Polar bears who prey on land animals for survival (coastal) have shifted their feeding habits over time because of melting arctic sea-ice, while bears that hunt for food in the ocean (pelagic) have higher levels of pollutants in their bodies. They too are forced to search for their food in wider feeding habitats, according to the study’s authors.

By studying the migration patterns, feeding habits, distance traveled to find food and how much energy a bear expends in their hunt, Blévin and his team were able to determine their results.

For one, bears that feed on food from the ocean eat much more marine life because of the long distances they travel and the amount of energy they spend in their travels. That journey is made even longer because more sea life has been forced to migrate due to warming waters and melting sea ice, according to the study.

The more prey the pelagic group consumes means more pollutants from animals higher up on the food chain. Researchers tested the pelagic group for pollutants along with their prey, like harp seals from Greenland which were found to have high levels of persistent organic pollutants (POPs).

These two groups of polar bears face different ecological challenges, because the sea-hunting bears are chasing a shrinking ice zone and migrating farther while longer ice-free periods in Svalbard – the Norwegian archipelago between mainland Norway and the North Pole – force coastal bears to feed on land-based prey.

“However, in the absence of sea ice, Barents Sea polar bears can feed opportunistically on alternative food sources such as ground-nesting bird, seabirds, bird eggs, reindeers, whale carcasses, algae, and even vegetation,” writes the study authors.

Since the 1990s, the Barents Sea polar bears have shifted their routes north due to changes in their habitat.

More travel means more energy expended, but it’s what’s waiting for these two groups that equates to the amount of pollutants they will ingest. This could be due to proximity to emission sources, the amount of pollution that is absorbed by their prey and transport routes they now find themselves in according to the study.

The study was published in the American Chemical Society’s Environmental Science & Technology.

A separate study released in November showed polluted food isn’t the only thing Arctic animals need to fear in the age of climate change: Harbor seals were found to be more susceptible to certain deadly pathogens as they are being forced to travel between the North Atlantic and the North Pacific oceans due to climate change.

A recent NASA study of 16 years of data on climate change showed the Arctic is melting from shorter winters, longer summers and the warmest years on record in 2015, 2017 and very likely 2019.

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