Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Determining Changes to Animals' Diet as a Result of Changes in Ecosystems

03.06.2011
It just takes a pinch. But from a sample of animal fat, Sara Iverson can determine what predators at the top of the food chain are eating, and by extension, how their diet has changed due to changes in ecosystems.

Changes in diet can be seen most dramatically in Arctic polar bears — “canaries in the coal mine when it comes to climate change,” according to Dr. Iverson, scientific director of the Ocean Tracking Network Canada and a University Research Professor at Dalhousie University in Halifax, Nova Scotia. She notes the polar bear is the first animal to be considered vulnerable because of the consequences of climate change. (Polar bears are listed as a threatened species under the Endangered Species Act in the U.S. and as a “species of special concern” in Canada.)

“Polar bears are absolutely dependent on sea ice to hunt seals, which use the ice as a platform to breed,” explains Dr. Iverson. “With the loss of ice, they’re having a difficult time. A major source of food has been removed and in some areas they’ve been forced ashore earlier in the spring in poor condition.”

Using the “quantitative fatty acid signature analysis” (or QFASA for short) she developed, Dr. Iverson, along with her graduate student Gregory Thiemann and Ian Stirling with the Canadian Wildlife Service, examined the diets of 1,700 polar bears across the Canadian Arctic over a 30-year period. The main food source for the bears were generally ringed seals— a food source that’s becoming scarce to the bears because of sea-ice breakup. Some bear populations have been able to adapt by taking advantage of other locally available prey such as harp seals and belugas. As well, larger polar bears were better able to cope by taking on walruses and large bearded seals.

QFASA has proven to be an important tool, allowing researchers to do their work without harm to the animals. Prior to its development, estimates of diet were imprecise and limited to only the animal’s last meal.

Even so, it can still be quite a process to obtain the samples required for analyses. For example, the male northern fur seal is notoriously vicious, given its massive size (340 kg) and predilection for fighting. To study fur seals, the researchers (three at a time) assemble in a plywood box with no ceiling or floor, and shuffle into the midst of the rookery. They bring females into the box one at a time, take samples and attach a tag, before releasing them again, all the while with one person on the lookout for the ornery males.

“You have to have a good sense of humor and there are times when you think, ‘what in the world am I doing here?’” she says. “But it is absolutely incredible to see these animals in their natural environment.”

Northern fur seals, which were hunted almost to extinction during the last century, have thrived on St. Paul Island in the Bering Sea since the hunting ban 100 years ago. However, now the northern fur seal population is crashing again, and researchers are trying to figure out why. Theories include nutritional limitation – food is scarce because of overfishing or climate change – or predation by killer whales which have also had to look for a new food source.

QFASA is one of several innovative tools researchers have to study marine mammals, which are elusive subjects because they spend so much of their time in the sea. Others include satellite tags, physiological and chemical tracers and “critter cams,” which let the researchers “see what the seal sees.”

But for Dr. Iverson, good, old-fashioned field work will always remain the true joy of her job.

“You go to spectacular places and work with amazing animals,” she says. “Sometimes I can’t believe they actually pay me to do this. You cannot be handed the data and have the same feel for it. Field work give you an insight you would not get otherwise.”

Charles Crosby | Newswise Science News
Further information:
http://www.dal.ca

Further reports about: Arctic Canadian Light Source DIET ecosystems food source fur seals polar bear

More articles from Ecology, The Environment and Conservation:

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

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: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>