Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

20.09.2013
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?


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. Photo: Rune Dietz, Aarhus University.

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.

Further information

Professor Rune Dietz, Aarhus University, Department of Bioscience and Arctic Research Centre. Tel: +45-8715 8690. Mobile: +45 21254035. Mail: rdi@dmu.dk.

Dr. Robert Letcher, Carleton University, Department of Chemistry. Tel: +011 613 998 6696. Mobile: +011 613 291 3563. Mail: robert.letcher@ec.gc.ca.

Read more

Causes and consequences of long-term change in East Greenland polar bears’ diets: Investigation using quantitative fatty acid estimates and fatty acid carbon isotope patterns. McKinney, M. et al. (2013). Global Change Biology 19: 2360-2372. doi: 10.1111/gcb.12241.

Part 1: Three decades (1984-2010) of legacy contaminant trends in East Greenland polar bears (Ursus maritimus). Dietz R. et al. (2013a). Environment International 59:485-493.

Part 2: Three decades (1984-2010) of flame retardant trends in East Greenland polar bears (Ursus maritimus). Dietz R. et al. (2013b). Environment International 59: 494-500.

Rune Dietz | EurekAlert!
Further information:
http://scitech.au.dk/en/current-affairs/news/show/artikel/climate-change-polar-bears-change-to-diet-with-higher-contaminant-loads/

More articles from Ecology, The Environment and Conservation:

nachricht Despite government claims, orangutan populations have not increased. Call for better monitoring
06.11.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Increasing frequency of ocean storms could alter kelp forest ecosystems
30.10.2018 | University of Virginia

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>