(Press-News.org) The first evidence for massive and abrupt iceberg calving in Antarctica, dating back 19,000 to 9,000 years ago, has now been documented by an international team of geologists and climate scientists. Their findings are based on analysis of new, long deep sea sediment cores extracted from the region between the Falkland Islands and the Antarctic Peninsula. The study in the May 28, 2014 issue of Nature bears witness to an unstable Antarctic ice sheet that can abruptly reorganize Southern Hemisphere climate and cause rapid global sea level rise.
"One of the iceberg events in our data that is of particular interest took place 14,600 years ago and coincided with a huge ice-sheet melt, the famous Meltwater Pulse 1A, which according to previous studies led to a global sea level rise of about 4 meters within 100 years," says lead author of the study, Michael Weber at the University of Cologne in Germany.
"This is the first direct evidence that instabilities of the Antarctic ice sheet caused rapid sea level rise during the last glacial termination," says co-author Peter Clark, professor at Oregon State University.
To determine what brought about such huge ice-sheet collapses in Antarctica, the team conducted a series of climate modeling experiments.
"An unusually strong flow of warm water towards Antarctica may have triggered these events. Our model experiments reveal further that the associated melting in turn increased the warm water flow, thus providing a positive feedback. This is a perfect recipe for rapid sea level rise," explains co-author Axel Timmermann, professor at the International Pacific Research Center of the University of Hawaii.
The new findings document that the Antarctic ice-sheet underwent rapid changes in an otherwise gradual transition from glacial to interglacial times in the Southern Hemisphere.
"Our paleo data of abrupt ice-sheet instabilities provide an important benchmark against which future projections of human-induced changes in Antarctic ice volume and global sea level can be evaluated," says Gerrit Lohmann, professor at the Alfred Wegener Institute, Bremerhaven, Germany.
INFORMATION:
Citation
Weber, M. E., Clark, P.U., Kuhn, G., Timmermann, A., Sprenk, D., Gladstone, R., Zhang, X., Lohmann, G., Menviel, L., Chikamoto, M. O., Friedrich, T. Ohlwein, C., 2014:
Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation, Nature
http://dx.doi.org/10.1038/nature13397
Author Contact Information
Michael Weber: Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, 50935 Cologne; email michael.weber@uni-koeln.de; phone xx49-221-470-7316.
Axel Timmermann: International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 96822; email axel@hawaii.edu; phone (808) 956-2720.
Funding and Acknowledgements
This study was supported by the Deutsche Forschungsgemeinschaft (DFG grant numbers We2039/7-1, Ri525/17-1 and Ku683/ 9-1), the University of Cologne, the US NSF Antarctic Glaciology Program (grant numbers ANT-1043517 and ANT-1341311), the US NSF Paleoclimatology Program, the Japan Agency for Marine-Earth Science and Technology, and Helmholtz funding through the Polar Regions and Coasts in the changing Earth System (PACES) program. Our study was also part of the Southern Ocean Initiative of the International Marine Past Global Change Study (IMAGES) program.
About the IPRC
The International Pacific Research Center (IPRC) of the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawaii at Manoa, is a climate research center founded to gain greater understanding of the climate system and the nature and causes of climate variation in the Asia Pacific region and how global climate changes may affect the region. Established under the "U.S. Japan Common Agenda for Cooperation in Global Perspective" in October 1997, the IPRC is a collaborative effort between agencies in Japan and the United States.
Antarctic ice-sheet less stable than previously assumed
2014-05-28
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
Filling in the gaps on the protein map
2014-05-28
By cataloging over 18,000 proteins, researchers from TUM have produced an almost complete inventory of the human proteome. This information is now freely available in the ProteomicsDB database, which is a joint development of TUM and software company SAP. The database includes information for example on the types, distribution, and abundance of proteins in various cells and tissues as well as in body fluids.
The investigations show that, on the one hand, around 10,000 proteins are concerned with housekeeping processes in many different places. On the other hand, it was ...
Zeroing in on the proton's magnetic moment
2014-05-28
As part of a series of experiments designed to resolve one of the deepest mysteries of physics today, researchers from RIKEN, in collaboration with the University of Mainz, GSI Darmstadt and the Max Planck Institute for Physics at Heidelberg, have made the most precise ever direct measurement of the magnetic moment of a proton.
The work, published in Nature today, seeks to answer the fundamental question of why we exist at all. It is believed that the Big Bang some 13 billion years ago generated equal amounts of matter and antimatter-which annihilate when they collide-and ...
Extensive cataloging of human proteins uncovers 193 never known to exist
2014-05-28
Striving for the protein equivalent of the Human Genome Project, an international team of researchers has created an initial catalog of the human "proteome," or all of the proteins in the human body. In total, using 30 different human tissues, the team identified proteins encoded by 17,294 genes, which is about 84 percent of all of the genes in the human genome predicted to encode proteins.
In a summary of the effort, to be published May 29 in the journal Nature, the team also reports the identification of 193 novel proteins that came from regions of the genome not predicted ...
New study finds Antarctic Ice Sheet unstable at end of last ice age
2014-05-28
CORVALLIS, Ore. – A new study has found that the Antarctic Ice Sheet began melting about 5,000 years earlier than previously thought coming out of the last ice age – and that shrinkage of the vast ice sheet accelerated during eight distinct episodes, causing rapid sea level rise.
The international study, funded in part by the National Science Foundation, is particularly important coming on the heels of recent studies that suggest destabilization of part of the West Antarctic Ice Sheet has begun.
Results of this latest study are being published this week in the journal ...
Major discovery on the mechanism of drug resistance in leukemia and other cancers
2014-05-28
A mechanism that enables the development of resistance to Acute Myeloid Leukemia (AML) anticancer drugs, thereby leading to relapse, has been identified by Kathy Borden of the University of Montreal's Institute for Research in Immunology and Cancer (IRIC) and her collaborators. Kathy Borden is a Principal Investigator at IRIC and a professor at the university's Department of Pathology and Cell Biology. The development of drug resistance is one of the main problems in clinical oncology and the cause of relapse in many patients.
The new discovery, recently published in ...
NASA's TRMM and Aqua satellites peer into Tropical Storm Amanda
2014-05-28
Hurricane Amanda has weakened to a tropical storm, but not before NASA's TRMM satellite took a look under its clouds at the rate of heavy rainfall it was generating. After weakening to a tropical storm, NASA's Aqua satellite identified that those strong thunderstorms were limited to the area around the center of its circulation.
The Tropical Rainfall Measuring Mission satellite known as TRMM passed over Amanda on Saturday May 24, 2014 at 2150 UTC (5:50 p.m. EDT). TRMM is a joint mission between NASA and the Japan Aerospace Exploration Agency known as JAXA.
At NASA's ...
Wild coho may seek genetic diversity in mate choice
2014-05-28
CORVALLIS, Ore. – A new study by researchers at Oregon State University suggests that wild coho salmon that choose mates with disease-resistant genes different from their own are more likely to produce greater numbers of adult offspring returning to the river some three years later.
The researchers also found that hatchery-reared coho – for some unknown reason – do not appear to have the same ability to select mates that are genetically diverse, which may, in part, explain their comparative lower reproductive success.
Results of the study have been published in this ...
Increased social network can have big payoff for nonprofits, study shows
2014-05-28
BUFFALO, N.Y. — Charitable fundraising once depended primarily upon a charity's size, efficiency and longstanding reputation. That was before Razoo, Chipin, Facebook and Twitter came to town.
In the first academic study to look at what determines charitable giving on social-media sites, researchers found that those media have created a more level playing field in the nonprofit world, one in which successful use of technology can make up for limited organizational size.
Technology and social media, it turns out, can not only raise the online profile of even small organizations, ...
How long should HCV treatment last? Study suggests answers are complex
2014-05-28
BUFFALO, N.Y. – As new treatments for hepatitis C virus (HCV) are approved, biomedical scientists are exploring their mechanisms and what they reveal about the virus. An online publication this month in Hepatology is the first to report real-time tracking of viral decay in the liver and blood in 15 patients with HCV.
Led by Andrew H. Talal, MD, University at Buffalo professor of medicine in the Division of Gastroenterology, Hepatology and Nutrition and corresponding author, the study is the first to trace in real-time how the drug telaprevir inhibits viral replication ...
Study affirms value of epigenetic test for markers of prostate cancer
2014-05-28
A multicenter team of researchers report that a commercial test designed to rule out the presence of genetic biomarkers of prostate cancer may be accurate enough to exclude the need for repeat prostate biopsies in many — if not most — men.
"Often, one biopsy is not enough to definitively rule out prostate cancer," says study researcher Jonathan Epstein, M.D., director of the Division of Surgical Pathology and a professor of pathology, urology and oncology at the Johns Hopkins University School of Medicine. "Our research finds that by looking for the presence or absence ...