2016-09-19

As Arctic sea ice declines as a result of climate change, polar bears -- which traverse sea ice in search of seals, their primary prey -- are in some parts of their range being forced to forage for food on land.

Polar bears have long been known to eat the likes of berries, kelp and birds' eggs to supplement their diet, generally while waiting for sea ice to form in fall or after coming ashore when the ice breaks up in late spring. Now, there's evidence such behavior is becoming more common. Indeed, some bears may be going to extra lengths to procure the precious calories that a nest of bird eggs may provide: In 2010, scientists

reported polar bears climbing rock cliff ledges

to eat murre eggs in Canada; and the following year, tourists in the Russian Arctic

saw a bear clambering down a cliff

populated by guillemots, presumably with the same goal in mind.

However, although there has been some speculation that these alternative food sources may

mitigate against the impacts

of sea ice loss, most researchers have been far more cautious in reaching such conclusions; and a pair of new papers suggests that such caution is merited.

RELATED: Hungry Polar Bears Decimating Seabird Colonies

In one, published in the journal

Global Change Biology ,

scientists worked with local Inuit to study the interaction between polar bears and common eiders on Baffin Island. "Inuit are very in tune to this type of environmental change because they hunt eiders for meat, and collect eggs and down from their nests,"

said study lead author

Cody Dey of the Great Lakes Institute for Environmental Research at the University of Windsor

in Ontario. However, that traditional hunting may be at risk, Dey and colleagues wrote, because "our research suggests that eiders might nest in different locations to avoid polar bear predation, which could make it harder for local people to harvest eiders."

Dey and his co-authors further found that polar bear predation of eider nests is likely to increase over the next 25 years, and that a large percentage of the nests will be consumed by polar bears in years with earlier sea ice melt.

WATCH: If Global Warming Is Real, Why Is Antarctic Sea Ice Growing?

However, despite that, Baffin Bay's polar bears will continue to get skinnier.

"When the sea ice is melted, polar bears are forced to fast until it freezes up again," said Dey. "Even if bears are eating eider eggs, they probably can't meet their caloric demand because eider eggs are relatively low in calories (compared to seals). Our models suggest that polar bears can't compensate for the loss of ice-based hunting opportunities by consuming eider eggs."

Related: Photographing Polar Bears on Thinning Ice (Video)

Another study, in the journal

Physiological and Biochemical Zoology,

paints, if anything, an even starker picture. Between 2009 and 2014, researchers weighed 142 polar bears that had wandered into the "polar bear capital" of Churchill, Manitoba and were captured and transferred to the town's bear holding facility, colloquially known as the

"polar bear jail."

The bears were given water but not food, to discourage them from returning to town once they were released.

During their stay, the bears lost about two pounds of body mass a day -- which, said lead author Andrew Derocher of the University of Alberta, is pretty much the same as the weight loss experienced by bears that forage on berries, kelp and goose eggs during the ice-free season along the coast of Hudson Bay. In other words, bears that gain their nutrition from land alone are not demonstrably better off than those that are forced to fast.

"It's not exactly a good news story for the bears," Derocher

told the Times Colonist newspaper

. "There's always been the question of what could those bears be getting from feeding out there. And, it turns out, not very much."

See Photos: Amazing Shots of Earth



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Whakaari, also known as White Island, is an active stratovolcano, situated 30 miles (48 kilometers) from the North Island of New Zealand in the Bay of Plenty. Whakaari is New Zealand's most active volcano, and has been built up by continuous eruptions over the past 150,000 years. The island is approximately 1.2 miles (2 kilometers) in diameter and rises to a height of 1,053 feet (321 meters) above sea level.

via

Daily Overview

, satellite imagery courtesy of Digital Globe



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The Northeast is suffering its worse drought in a decade,

according to NASA

. A high-pressure ridge has stalled over the Southeast, pushing storms farther north than usual. It's left much of New York and New England with far less rain than usual.



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August 2016 satellite photos show a rift on the glacier in Antarctica called Larsen C is much longer than previously thought. The rift could lead to a collapse similar to the one that occurred to the Larsen B ice shelf. "We don't know yet what will happen here,"

said Ala Khazendar of NASA's Jet Propulsion Laboratory

on the NASA Earth Observatory site.

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Lombard Street runs from east to west in San Francisco. With eight hairpin turns dispersed over a one-block section in the Russian Hill neighborhood, Lombard is often referred to as "the most crooked street in the world."

via

Daily Overview

, satellite imagery courtesy of Digital Globe

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Glacial melting and flooding occurs every year by the Skafta River in Iceland. As the water travels down towards the North Atlantic Ocean, incredible patterns are created on the hillsides. Rising lava, steam vents, or newly opened hot springs can all cause this rapid ice melt, leading to a sizable release of water that picks up sediment as it flows down from the glaciers.

via

Daily Overview

, satellite imagery courtesy of Digital Globe

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The Daldykan River in Siberia turned red in early September, apparently from pollution.

Sadly, it isn't the first time that the river has turned red. A user on the Russian social media site VK.com posted

similar pictures back in 2014

.

Credit: Association of Indigenous Peoples of Taimyr, via Facebook

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Scientists have discovered an entirely new genus of bacteria living in hydraulic fracking wells, part of a thriving ecosystem of microorganisms that contains at least 31 different species.

Credit:

Michael Wilkins, courtesy Ohio State University

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A dance group performs on the cliffs in Zhangjiajie, Hunan province, in China.

Credit:

China Daily/via REUTERS

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