Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research Team Advances Knowledge of Antarctica's Climate History

11.08.2008
North Dakota State University researchers, Fargo, are among the leaders of a group of National Science Foundation-funded scientists who have discovered the last traces of tundra on the interior of Antarctica before temperatures began a relentless drop millions of years ago.

The collaboration’s research, which resulted in a major advance in the understanding of Antarctica’s climatic history, appears in the Aug. 4 issue of the Proceedings of the National Academy of Sciences.

The international team of scientists headed up by NDSU geoscientists Allan Ashworth and Adam Lewis and David Marchant, an earth scientist at Boston University, combined evidence from glacial geology, paleoecology, dating of volcanic ashes and computer modeling, to report a major climate change centered on 14 million years ago. The three scientists often spend months living in tents in the Transantarctic Mountains’ Dry Valleys doing their research.

They have documented the timing and magnitude of the continent’s shift from warm, temperate glaciers and fringing tundra to polar glaciers and polar tundra. “The contrast couldn’t be more striking,” Marchant said. “It is like comparing Tierra del Fuego today with the surface of Mars—and this transition took place over a geologically short interval of roughly 200,000 years.”

According to Lewis, the discovery of lake deposits with perfectly preserved fossils of mosses, diatoms and ostracods is particularly exciting to scientists. “They are the first to be found even though scientific expeditions have been visiting the Dry Valleys since their discovery during the first Scott expedition in 1902-03,” said Lewis.

For Ashworth, the fossils are a paleoecological treasure trove. He notes that some ancient species of diatoms and mosses are indistinguishable from the ones today, which occur throughout the world except Antarctica.

“To be able to identify living species amongst the fossils is phenomenal. To think that modern counterparts have survived 14 million years on Earth without any significant changes in the details of their appearances is striking,” said Ashworth, the principal paleoecologist in the research. “It must mean that these organisms are so well-adapted to their habitats that in spite of repeated climate changes and isolation of populations for millions of years, they have not become extinct but have survived.”

The fossil finds and dating of volcanic ash show that roughly 14.1 million years ago, the area was home to tundra, “wet” glaciers typical of those of the mountains of Tierra Del Fuego in the high southern latitudes and seasonally ice-free lakes. The beds of the long-gone lakes contain layers of sediments where dying plants and insects accumulated and were preserved.

The mean summertime temperatures would have dropped in that period by as much as 8 degrees Celsius. On average, the summertime temperatures in the Dry Valleys 14.1 million years ago would have been as much as 17 degrees warmer than the present-day average.

According to Lewis, the freshness of the crystals and glass in the volcanic ash and the preservation of cellular detail in the fossils indicate they have been permanently frozen since 13.9 million years ago.

The research conclusion suggests that even when global atmospheric temperatures were warmer than they are now, as occurred 3.5 million years ago during the Pliocene Epoch, and as might occur in the near future as a consequence of global warming, there was no significant melting of the East Antarctic ice sheet inland of the Dry Valleys. According to Ashworth, if this conclusion stands the test of time, it suggests a very robust ice sheet in this sector of Antarctica, and emphasizes the complex and non-uniform response of Antarctica’s ice sheets to global change.

He adds, "The huge uncertainties regarding the inherently unstable marine-based West Antarctic ice sheet, however, make all predictions about the future based on past behavior educated guesses at best.”

The National Science Foundation, in its role as the manager of the United States Antarctic Program, supported the work of Ashworth, Lewis and Marchant as well as United States researchers from Lamont-Doherty Earth Observatory, Ohio State University and the University of Montana.

The work of the research team in the field also appears in the documentary “Ice People” by Emmy-award-winning director Anne Aghion. The film will be screened in science museums throughout Australia during the month of August and will air on SBS Australian Television on August 24. Ice People received support from the National Science Foundation’s Antarctic Artists and Writers Program. It has been screened at international film festivals in New York, San Francisco and Jerusalem and is scheduled to air on the Sundance Channel in 2009.

For more information about the study:
http://www.ndsu.nodak.edu/instruct/ashworth/Boreas/index.htm
Proceedings of the National Academy of Sciences
http://www.pnas.org/content/105/31/10676

Steven Bergeson | Newswise Science News
Further information:
http://www.ndsu.nodak.edu/
http://www.ndsu.nodak.edu/instruct/ashworth/Boreas/index.htm
http://www.icepeople.com

More articles from Earth Sciences:

nachricht Monitoring lava lake levels in Congo volcano
16.05.2018 | Seismological Society of America

nachricht Ice stream draining Greenland Ice Sheet sensitive to changes over past 45,000 years
14.05.2018 | Oregon State University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>