. 24/7 Space News .
ICE WORLD
Geoscientific evidence for subglacial lakes
by Staff Writers
Bremerhaven, Germany (SPX) Jun 05, 2017


file image

During the last glacial period - when the ice in the Antarctic was far thicker and extended further offshore than it does today - it has been speculated that subglacial lakes existed beneath it. An international team of researchers has now successfully sampled the metre-thick sediment layers left behind by these lakes contemporary on the seafloor. This is the outcome of a study by Gerhard Kuhn and colleagues, which was published in the journal Nature Communications.

Hundreds of subglacial lakes currently exist beneath the Antarctic Ice Sheet, with Lake Vostok being the largest and best known. The challenges involved in exploring these lake systems, which have remained enclosed for thousands of years, are enormous.

For instance, scientists must adhere to strict environmental restrictions so as to avoid polluting the lakes, which involves considerable resources. To date, Russian researchers have only collected samples by drilling into the surface ice of Lake Vostok and testing the water that poured out of the borehole before promptly refreezing.

Now a team of researchers led by marine geologist Dr Gerhard Kuhn from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have provided unequivocal evidence, in the form of pore water analyses, for the presence of a former subglacial lake on the Antarctic continental shelf. During expeditions to the Amundsen Sea with the Research Icebreaker Polarstern in 2006 and 2010, AWI researchers and their international colleagues collected sediment cores that they now confirm are from subglacial lakes.

"The cores, which are up to ten metres long, were collected at a water depth of 750 metres. The lake sediments are currently buried under a four-metre thick layer of marine sediment on the seafloor," Kuhn reports. They were retrieved from valleys on the ocean floor that were situated under the Antarctic Ice Sheet in the Earth's distant past.

"We have now verified that, during the last glacial period, there were also subglacial lakes under a massively thick ice sheet in Pine Island Bay in the southern Amundsen Sea. The ice there has now dramatically retreated, which allowed us to sample palaeo-lake sediments from aboard Polarstern," says the first author of the Nature Communications study, in which the researchers will share their findings today.

"In this regard, we measured the chloride content in the pore water as an indicator of its salinity. In the lower parts of some sediment cores, it was extremely low: a clear sign of freshwater, which originates from lakes under the ice," explains co-author and AWI geochemist Dr Sabine Kasten.

"We modelled the exchange of freshwater in the porous spaces of the sediment with the overlying seawater, to help us reconstruct the dynamics of the transition from a lake to a marine environment," reports Dr Jose Mogollon from the University of Utrecht. The unique sediments the team collected now provide an archive of changing environmental conditions in the Antarctic and cover a timespan from the present to the Last Glacial Maximum (ca. 21,000 years ago), when the global sea level was roughly 130 metres lower than today.

These lake sediments contain components that are virtually impossible to date, which narrows scientists' ability to estimate their age. "We do know, however, that roughly 11,000 years ago Pine Island Glacier retreated and thinned, causing the moving ice to float on the ocean as an ice shelf.

As a result, the lakes that were previously covered by glaciers disappeared into the ocean, when it flooded the Antarctic continental shelf. Only the imprint of the lakes in the form of deep basins and sediments remained preserved, which we have now investigated," says Dr Claus-Dieter Hillenbrand from the British Antarctic Survey.

Satellite-monitoring shows that the movement of water from one lake to another can cause glaciers draining the Antarctic Ice Sheet to move more quickly. "This aspect needs to be taken into account in models designed to make predictions on the future behaviour and dynamics of ice masses, and with them, the degree to which the sea level will rise," explains AWI marine geologist Kuhn.

According to a second study, which Kuhn contributed to and was published in Nature Communications on 17 March 2017, he added: "We have every reason to believe that there are more subglacial lakes in the Antarctic - and more so in the last glacial period - than has been previously assumed. In addition, icecaps like those on the sub-Antarctic island South Georgia and ice sheets reacted much more sensitively and rapidly to climate changes than previously assumed."

Research paper

ICE WORLD
New Light on the Future of a Key Antarctic Glacier
Pasadena CA (JPL) Jun 01, 2017
The melt rate of West Antarctica's Thwaites Glacier is an important concern, because this glacier alone is currently responsible for about 1 percent of global sea level rise. A new NASA study finds that Thwaites' ice loss will continue, but not quite as rapidly as previous studies have estimated. The new study, published in the journal Geophysical Research Letters, finds that numerical mod ... read more

Related Links
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research
Beyond the Ice Age


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

ICE WORLD
Russia on the Way to Adopt New Program on Development of Space Centers

Astronauts return after marathon ISS mission

From 2D to 3D, Space Station Microscope Gets an Upgrade

Studying Flame Behavior in Microgravity with a Solid "High-Five"

ICE WORLD
Ariane 5 launches its heaviest telecom payload

SpaceX blasts off cargo using recycled spaceship

Ariane 5 launches its first all-electric satellite

India launches GSLV in heavy lift configuation

ICE WORLD
Curiosity Peels Back Layers on Ancient Martian Lake

Student-Made Mars Rover Concepts Lift Off

Illinois Company Among Hundreds Supporting NASA Mission to Mars

Halos discovered on Mars widen time frame for potential life

ICE WORLD
California Woman Charged for Trying to Hand Over Sensitive Space Tech to China

A cabin on the moon? China hones the lunar lifestyle

China tests 'Lunar Palace' as it eyes moon mission

China to conduct several manned space flights around 2020

ICE WORLD
Propose a course idea for the CU space minor

Leading Global Air And Space Law Group Joins Reed Smith

New Horizons for Alexander Gerst

Government space program spending reaches 62B dollars in 2016

ICE WORLD
Bamboo inspires optimal design for lightness and toughness

New sound diffuser is 10 times thinner than existing designs

Mitsubishi Electric Completes New Satellite Component Production Facility

BAE Systems, Helios to collaborate on liquid armor

ICE WORLD
Citizen scientists uncover a cold new world near sun

Giant Ringed Planet Likely Cause of Mysterious Eclipses

New Collaboration with Jodrell Bank Observatory for SETI

Viable Spores, DNA Fragments Discovery at ISS Justifies Biosphere's Expansion

ICE WORLD
A whole new Jupiter with first science results from Juno

First results from Juno show cyclones and massive magnetism

Jupiters complex transient auroras

NASA's Juno probe forces 'rethink' on Jupiter









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.