Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Antarctic life hung by a thread during ice ages

18.02.2008
Frozen in time… frozen in place… frozen solid… All of these phrases have been used to describe Antarctica, and yet they all belie the truth about this southerly point on the globe.

Although the area is covered in ice and bears witness to some of the most extreme cold on the planet, this ecosystem is dynamic, not static, and change here has always been dramatic and intense.

A report published in the March issue of Ecology argues that the extreme cold and environmental conditions of past Ice Ages have been even more severe than seen today and changed life at the Antarctic, forcing the migration of many animals such as penguins, whales and seals. Understanding the changes of the past may help scientists to determine how the anticipated temperature increases of the future will work to further transform this continent.

Extreme cold and lasting darkness have always worked to limit the productivity of the microscopic algae in Antarctica. The availability of such algae drives the entire region’s food web, from one-celled organisms to top predators such as whales and seals, making life in this region challenging for all kinds of animals.

But during the Ice Ages, animals in Antarctica faced conditions even more life-threatening. Massively thick and permanent ice covered most of the land, and sea-ice coverage around the continent was permanent. The Antarctic continental shelf was glaciated and most seafloor animals dodged extinction by emigrating into deeper waters.

Sven Thatje from the University of Southampton’s School of Ocean and Earth Science (UK) has been studying geological records of the area for such insights. He and his team from the British Antarctic Survey in Cambridge and the German Alfred Wegener Institute have found that penguins, whales and seals were very dependant upon areas of open water known as polynyas. The polynyas, the team contends, must have existed far south of the present winter sea-ice boundaries, and far north of the Antarctic shelf.

Polynyas have been important both in the past and today because they cause upswells of warmer water, and thereby help establish local food webs for many animals.

Thatje’s team analyzed geologic and genetic records and found that during glacial periods the permanent sea-ice belt advanced much further to the North than it is now. In parts of the Southern Ocean, the summer sea-ice boundary was located where the winter sea-ice limit is today, and ice coverage was complete and a magnitude thicker than seen today. These boundaries would have forced a complete shut down of food supplies for most life, both from the sea and land.

Only species that are champions of cold weather adaptation in the present day, such as Emperor Penguins and Snow Petrels, were likely able to survive in locally restricted areas of biological productivity. Those animals, it seems likely, may have stayed in Antarctica during the Ice Ages.

But the polynyas were too isolated to support larger top predators, such as seals and whales, which had to move north to escape starvation. Many other penguin species lost access to traditional feeding grounds and ice-free breeding areas on land, which are crucial for their survival. Some of those animals may have thus been forced to emigrate as far north as the Patagonian shelf off the coast of what is now Argentina.

“Science is only now beginning to ponder what happened here during the Ice Ages,” says Thatje. “This research is leading to a radical reconsideration of those time periods. Antarctic species are champions in adaptations to extreme cold and the harshest environmental conditions. Understanding how the stunning Antarctic fauna has evolved and coped with glacial-interglacial periods will help us to assess their sensitivity to current climate warming.”

Thatje also notes that the animals of Antarctica are extremely vulnerable to warming temperatures. Their ability to survive in extreme cold is unique and has taken tens of millions of years to evolve.

Shifts in the distribution of animals over glacial cycles have likely been a very common phenomenon in region, he says. But given the fact that sub-Antarctic organisms are invading the area as temperatures rise, Thatje says it is time to assess how and if the Antarctic ecosystems will be able to cope with the new invaders.

Nadine Lymn | EurekAlert!
Further information:
http://www.esa.org

More articles from Ecology, The Environment and Conservation:

nachricht Safeguarding sustainability through forest certification mapping
27.06.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

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: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>