Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Greenland's ancient forests shed light on stability of ice sheet

06.07.2007
Ice cores drilled from southern Greenland have revealed the first evidence of a surprisingly lush forest that existed in the region within the past million years. The findings from an international study published today in the journal Science suggest that the southern Greenland ice sheet may be much more stable against rising temperatures than previously thought.

Researchers analysed ice cores from a number of locations in Greenland, including Dye 3 in the south of the country. From the base of the 2km deep Dye 3 core, they were able to extract what they believe is likely to be the oldest authenticated DNA obtained to date.

By analysing these DNA samples, the researchers identified a surprising variety of plant and insect life, including species of trees such as alder, spruce, pine and members of the yew family, as well as invertebrates related to beetles, flies, spiders, butterflies and moths. The researchers believe that the samples date back to between 450,000 and 800,000 years ago.

"We have shown for the first time that southern Greenland, which is currently hidden under more than 2km of ice, was once very different to the Greenland we see today," explains Professor Eske Willerslev, a Wellcome Trust Bioarchaeology Fellow from the University of Copenhagen, who led the study."Back then, it was inhabited by a diverse array of conifer trees and insects."

The research implies that ancient forests covered southern Greenland during a period of increased global temperatures, known as an interglacial period. When temperatures fell again, the area became covered in ice. This ice sheet appears to have remained during the last interglacial period (116,000-130,000 years ago) when the temperature was 5°C warmer than today, contrary to the view currently held by scientists. Professor Dorthe Dahl-Jensen, also at the University of Copenhagen, has shown that in fact, even during this interglacial period, the ice thickness at Dye 3 would have been reduced to between 1 km to 1.5km.

"If our data is correct, then this means that the southern Greenland ice cap is more stable than previously thought," says Professor Willerslev. "This may have implications for how the ice sheets respond to global warming."

However, Professor Willerslev was keen to dismiss the idea that this meant sea levels would not rise to the levels predicted by scientific models.

"We know that during the last interglacial, sea levels rose by 5-6m, but this must have come from other sources additional to the Greenland ice cap, such as Antarctic ice. I would anticipate that as the Earth warms from man-made climate change, these sources would still contribute to a rise in sea levels."

The results also show conclusively that ancient biomolecules from the base of ice cores can be used by scientists to reconstruct the environments hidden underneath ice-covered areas and can yield insights into the climate and the ecology of communities from the distant past.

"Analysing ancient biomolecules from beneath glaciers and ice sheets is challenging due to the very low concentrations, but the information is worth the effort," says Dr Enrico Cappellini, a member of the University of York's new PALAEO Group and another of the paper's co-authors, whose work is supported by the European Commission. "Our study suggests a solution to this problem. Given that ten per cent of the Earth's terrestrial surface is covered by thick ice sheets, it could open up a world of new discoveries."

Craig Brierley | EurekAlert!
Further information:
http://www.wellcome.ac.uk

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF

nachricht Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.

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: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>