Increased sea ice drift puts polar bears on faster-moving treadmill

June 7, 2017, University of Wyoming
Polar Bear (Ursus maritimus) near Kaktovik, Barter Island, Alaska. Credit: Alan Wilson/Wikipedia.

A new study led by the U.S. Geological Survey (USGS) and the University of Wyoming found that increased westward ice drift in the Beaufort and Chukchi seas requires polar bears to expend more energy walking eastward on a faster-moving "treadmill" of sea ice.

These findings represent the first assessment of the consequences of changing drift rates for , one of several previously unexplored effects of .

"Increased sea ice drift rates likely exacerbate the physiological stress due to reduced foraging opportunity already experienced by many polar bears in the warming Arctic," says George Durner, research ecologist with the USGS and lead author of the report, "adding yet another 'straw to the camel's back.'"

The results were derived from radio-tracking data of collared adult female polar bears in the Beaufort and Chukchi seas, coupled with sea ice drift data from the National Snow and Ice Data Center (NSIDC). The data, composed of over 77,000 bear locations and matching values, were collected during two periods with different sea ice characteristics, 1987-98 and 1999-2013.

"These were very intensive analyses requiring advanced computational capabilities," says Shannon Albeke, a spatial ecologist with UW's Wyoming Geographic Information Science Center. "It was probably the most complicated analysis of my career."

Credit: University of Wyoming

"This study demonstrates the unparalleled value of long-term uninterrupted data collection," says Professor Merav Ben-David of UW's Department of Zoology and Physiology. "Without access to the ice data from NSIDC, and the interagency and international cooperation, we could not have conducted this project."

The study estimates that polar bears must catch and consume one to three more seals per year (a 2-6 percent increase) in order to compensate for the higher expenditure of living on faster-drifting ice. This elevated energy expenditure is concurrent with a diminished availability of sea ice suitable for hunting seals, due to early ice melt in spring and expansive ice melt during summer.

The need to travel longer distances coincides with deterioration of the ice surface, on which polar bears walk, creating a complex and difficult environment to traverse. The study showed that, during the recent period, a solitary adult female polar bear required between 2.8 million and 3.2 million kilocalories annually. This was 51,000-107,000 kilocalories more than during the early period and is 3.5-4 times greater than total energy requirements of a moderately active adult human female.

Explore further: Sea ice loss associated with increased summer land use by Chukchi Sea polar bears

More information: George M. Durner et al. Increased Arctic sea ice drift alters adult female polar bear movements and energetics, Global Change Biology (2017). DOI: 10.1111/gcb.13746

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14 comments

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MR166
4 / 5 (4) Jun 07, 2017
And yet polar bear populations are increasing and at decade highs. This is just another example of people with useless degrees sucking monies from the government teat.
Whaleblubber
4 / 5 (4) Jun 07, 2017
They are becoming healthier because the treadmill is faster-moving therefore the population has increased? More soda and fries please
MR166
3.4 / 5 (5) Jun 07, 2017
Now if we could only turn them vegan they would be REALLY healthy . HeHe!
marcoantonio649
3 / 5 (4) Jun 07, 2017
After the data manipulation by NOAA, NASA, East Anglia University, the UN, and other peer-coordinated individuals, Why would I believe the data from NSIDC?
JohnDonohue
2 / 5 (4) Jun 07, 2017
Wait ... please explain this to me, a rational knowlege worker, if not a climate scientist.
1) the seals give birth on ice, not in the water, in the spring. They rest on ice, also.
2) the area of ice is shrinking;
3) bears eat baby seals alive;
4) there is a greater concentration of baby seals to eat now, per square mile of ice.

Joy for bears.
greenonions1
5 / 5 (2) Jun 07, 2017
MR166
And yet polar bear populations are increasing and at decade highs.
One of the most frequent myths we hear about polar bears is that their numbers are increasing and have, in fact, more than doubled over the past thirty years.
- From - https://polarbear...booming/
Spreading misinformation - makes you either uninformed, or a troll. Which would it be?
AGreatWhopper
5 / 5 (1) Jun 07, 2017
Both. That's why they're here. And after a decade, your progress against it?

Time to rethink.

Time to feed the deniers to the polar bears. It's good karma.
greenonions1
5 / 5 (1) Jun 07, 2017
your progress against it?
A big fat 0. But I just watched Buffy the Vampire Slayer - and one of the messages was that no matter how many times you kill the evil dudes - there are more of them to kill tmrw - but you cannot give up. We can't allow the trolls to silence us - then they really have won...
MR166
not rated yet Jun 07, 2017
greenonions1
5 / 5 (1) Jun 07, 2017
INCREASING!!!!!!!
Unless you dig a little - instead of getting your science info from the Daily Caller. If you actually looked at the science sites - that your rag article was based on - you would see a very different picture. http://polarbears...e/status
http://wwf.panda....ulation/
So let's dig a little into your Daily Caller misinformation. The first link they provide takes you to the known misinformation blog of Susan Crockford. She crops up on every anti science article regarding Polar Bears. Here - read a bit about Crockford - and also the Daily Caller. If you actually read the science - instead of right wing outrage media sites - you would come across this kind of truth.
scientists don't have solid figures on the total number of polar bears worldwide. They lack data on some populations, specifically those in Russia and East Greenland.
Cont.
MR166
not rated yet Jun 07, 2017
Onions is this more to your liking?

https://polarbear...t-30000/
greenonions1
5 / 5 (1) Jun 07, 2017
From - http://polarbears...e/status Now you can link from Crockford's misinformation - the the actual science of counting polar bears - and see that she is referencing a population of Bafin Bay, and Kane Basin. These are 2 sub populations - and do not necessarily reflect the overall population numbers. The facts regarding polar bears - is that they are very difficult to count - hard numbers are not available - due to this problem - and declarative statements about population trends are very problematic. So announcing on a science site that their numbers are INCREASING - when this conflicts with the scientific position - makes you a troll. Willie reads the Daily Mail - and you pick the Daily Caller - both rags - and not science.
greenonions1
5 / 5 (1) Jun 07, 2017
Onions is this more to your liking?

No troll - it is not. I already addressed the Susan Crockford blog - that is well understood in the Polar Bear community. She is a paid shill. Why don't you just look at the science - instead of immediately heading to the paid shill sites - that of course support your pre-outraged position. OMG all the scientists are lying - when they say that the trends in terms of #'s of polar bears are very problematic - due to insufficient data. That does not negate the concern the scientists have over the loss of habitat for the bears. Troll.
Da Schneib
5 / 5 (1) Jun 07, 2017
This is one of those times when the #climatecranks pick a really old and unreliable number for something, then pick a new number, then draw a straight line between them. The line goes the way they want, so they use that and keep repeating it even though it's stupid and doesn't actually constitute evidence of anything.

In short, another #climatecrank lie.

Good link, @greenos.

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