Featured Research

from universities, journals, and other organizations

Climate change: Polar bears change to diet with higher contaminant loads

Date:
September 20, 2013
Source:
Aarhus University
Summary:
Over the past 30 years, polar bears have increasingly exchanged ringed seal with harp seal and hooded seal in their diet. This change exposes the polar bear to more contaminants, according to a recent international study.

Harp seal with cub. Polar bears increasingly exchange ringed seal with harp seal and hooded seal in their diet and therefore become exposed to higher concentrations of contaminants.
Credit: Rune Dietz, Aarhus University

Over the past 30 years, polar bears have increasingly exchanged ringed seal with harp seal and hooded seal in their diet. This change exposes the polar bear to more contaminants, according to a recent international study.

Researchers expect the climate to become warmer in the future and predict that climate change will have a significant impact on the Arctic. How will a warming Arctic affect the polar bears?

The East Greenlandic population of polar bears resides in an area, where the Arctic sea ice is expected to disappear very late. However, the decline in the ice sheet here occurs at a rate of almost 1% per year, one of the highest rates measured in the entire Arctic region.

How does this affect the prey of the polar bears -- and, in turn, the polar bears' intake of contaminants? An international team of researchers set out to explore this question. The team counted researchers from the Greenland Institute of Natural Resources, Aarhus University (Denmark) and a number of Canadian institutions including: Dalhousie University, Great Lakes Institute for Environmental Research, University of Windsor, Carleton University and the National Water Research Institute.

The researchers studied the fatty acid profiles in the adipose tissue from a unique material of 310 polar bears hunted by East Greenland Inuits from the Scoresbysund area in the years from 1984 to 2011. The composition of fatty acids in the fat tissue of the polar bears namely reflects the profile of fatty acids in their diet.

The results show that the polar bears primarily feed on three species of seals: the high Arctic ringed seal and the two sub-Arctic species harp seal and hooded seal. Moreover, the results showed that the diet of the polar bears had changed over the almost 30 years during which the samples were collected. In this period, the average relative decline in the ringed seal's significance for the polar bears diet was 42%. Similarly, the intake of the sub-Arctic seals increased during the same period. Also, the researchers found that polar bears are generally in better condition now, so at a first glance the polar bears should be happy with this development.

Climate change undermines improvements

There are, however, a couple of problems that might mar the happiness, explains Professor Rune Dietz, Aarhus University:

"The problem is that the sub-Arctic seals that the polar bear has switched to, have a higher content of contaminants because they live closer to the industrialised world and are higher up in the food chain. Therefore, climate change undermines the improvements that you would otherwise have obtained owing to international regulations in the use of environmental use of persistent organic pollutants (POPs). We can see that the content of the POPs after year 2000 decreases slower in the polar bear than in, the ringed seal."

In the long term, the polar bear may very well lose access to the sub-Arctic seals as these depend on packed ice where they give birth to their cubs and are exposed to sunlight allowing them to form vital vitamin D.


Story Source:

The above story is based on materials provided by Aarhus University. The original article was written by Jens C. Pedersen. Note: Materials may be edited for content and length.


Journal References:

  1. Melissa A. McKinney, Sara J. Iverson, Aaron T. Fisk, Christian Sonne, Frank F. Rigét, Robert J. Letcher, Michael T. Arts, Erik W. Born, Aqqalu Rosing-Asvid, Rune Dietz. Global change effects on the long-term feeding ecology and contaminant exposures of East Greenland polar bears. Global Change Biology, 2013; 19 (8): 2360 DOI: 10.1111/gcb.12241
  2. Rune Dietz, Frank F. Rigét, Christian Sonne, Erik W. Born, Thea Bechshøft, Melissa A. McKinney, Robert J. Letcher. Three decades (1983–2010) of contaminant trends in East Greenland polar bears (Ursus maritimus). Part 1: Legacy organochlorine contaminants. Environment International, 2013; 59: 485 DOI: 10.1016/j.envint.2012.09.004
  3. Rune Dietz, Frank F. Rigét, Christian Sonne, Erik W. Born, Thea Bechshøft, Melissa A. McKinney, Robert J. Drimmie, Derek C.G. Muir, Robert J. Letcher. Three decades (1983–2010) of contaminant trends in East Greenland polar bears (Ursus maritimus). Part 2: Brominated flame retardants. Environment International, 2013; 59: 494 DOI: 10.1016/j.envint.2012.09.008

Cite This Page:

Aarhus University. "Climate change: Polar bears change to diet with higher contaminant loads." ScienceDaily. ScienceDaily, 20 September 2013. <www.sciencedaily.com/releases/2013/09/130920094748.htm>.
Aarhus University. (2013, September 20). Climate change: Polar bears change to diet with higher contaminant loads. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2013/09/130920094748.htm
Aarhus University. "Climate change: Polar bears change to diet with higher contaminant loads." ScienceDaily. www.sciencedaily.com/releases/2013/09/130920094748.htm (accessed April 23, 2014).

Share This



More Earth & Climate News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

California Drought Is Good News for Gold Prospectors

California Drought Is Good News for Gold Prospectors

AFP (Apr. 22, 2014) — For months California has suffered from a historic drought. The lack of water is worrying for farmers and ranchers, but for gold diggers it’s a stroke of good fortune. With water levels low, normally inaccessible areas are exposed. Duration: 01:57 Video provided by AFP
Powered by NewsLook.com
Raw: MN Lakes Still Frozen Before Fishing Opener

Raw: MN Lakes Still Frozen Before Fishing Opener

AP (Apr. 22, 2014) — With only three weeks until Minnesota's fishing opener, many are wondering if the ice will be gone. Some of the Northland lakes are still covered by up to three feet of ice, causing concern that just like last year, the lakes won't be ready. (April 22) Video provided by AP
Powered by NewsLook.com
Is North Korea Planning Nuclear Test #4?

Is North Korea Planning Nuclear Test #4?

Newsy (Apr. 22, 2014) — South Korean officials say North Korea is preparing to conduct another nuclear test, but is Pyongyang just bluffing this time? Video provided by Newsy
Powered by NewsLook.com
Nasa Gives You An Excuse to Post a Selfie on Earth Day

Nasa Gives You An Excuse to Post a Selfie on Earth Day

TheStreet (Apr. 22, 2014) — NASA is inviting all social media users to take a selfie of themselves alongside nature and to post it to Twitter, Facebook, Flickr, Instagram, or Google Plus with the hashtag #globalselfie. NASA's goal is to crowd-source a collection of snapshots of the earth, ground-up, that will be used to create one "unique mosaic of the Blue Marble." This image will be available to all in May. Since this is probably one of the few times posting a selfie to Twitter won't be embarrassing, we suggest you give it a go for a good cause. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins