WASHINGTON -- In one of the most remote lakes of Antarctica, nearly 65
feet beneath the icy surface, scientists from NASA, the Desert Research
Institute (DRI) in Reno, Nev., the University of Illinois at Chicago,
and nine other institutions, have uncovered a community of bacteria.
This discovery of life existing in one of Earth's darkest, saltiest and
coldest habitats is significant because it helps increase our limited
knowledge of how life can sustain itself in these extreme environments
on our own planet and beyond.
Lake Vida, the largest of several unique lakes found in the McMurdo Dry Valleys, contains no oxygen, is mostly frozen and possesses the highest nitrous oxide levels of any natural water body on Earth. A briny liquid, which is approximately six times saltier than seawater, percolates throughout the icy environment where the average temperature is minus 8 degrees Fahrenheit. The international team of scientists published their findings online Nov. 26, in the Proceedings of the National Academy of Sciences Early Edition.
"This study provides a window into one of the most unique ecosystems on Earth," said Alison Murray, a molecular microbial ecologist and polar researcher at the DRI and the report's lead author. "Our knowledge of geochemical and microbial processes in lightless icy environments, especially at subzero temperatures, has been mostly unknown up until now. This work expands our understanding of the types of life that can survive in these isolated, cryoecosystems and how different strategies may be used to exist in such challenging environments."
Despite the very cold, dark and isolated nature of the habitat, the report finds the brine harbors a surprisingly diverse and abundant variety of bacteria that survive without a current source of energy from the sun. Previous studies of Lake Vida dating back to 1996 indicate the brine and its inhabitants have been isolated from outside influences for more than 3,000 years.
"This system is probably the best analog we have for possible ecosystems in the subsurface waters of Saturn's moon Enceladus and Jupiter's moon Europa," said Chris McKay, a senior scientist and co-author of the paper at NASA's Ames Research Center, Moffett Field, Calif.
Murray and her co-authors and collaborators, including Peter Doran, the project's principal investigator at the University of Illinois at Chicago, developed stringent protocols and specialized equipment for their 2005 and 2010 field campaigns to sample from the lake brine while avoiding contaminating the pristine ecosystem.
"The microbial ecosystem discovered at Lake Vida expands our knowledge of environmental limits for life and helps define new niches of habitability," said Adrian Ponce, co-author from NASA's Jet Propulsion Laboratory, Pasadena, Calif., who enumerated viable bacterial spore populations extracted from Lake Vida.
To sample unique environments such as this, researchers must work under secure, sterile tents on the lake's surface. The tents kept the site and equipment clean as researchers drilled ice cores, collected samples of the salty brine residing in the lake ice and assessed the chemical qualities of the water and its potential for harboring and sustaining life.
Geochemical analyses suggest chemical reactions between the brine and the underlying iron-rich sediments generate nitrous oxide and molecular hydrogen. The latter, in part, may provide the energy needed to support the brine's diverse microbial life.
Additional research is under way to analyze the abiotic, chemical interactions between the Lake Vida brine and its sediment, in addition to investigating the microbial community by using different genome sequencing approaches. The results could help explain the potential for life in other salty, cryogenic environments beyond Earth, such as purported subsurface aquifers on Mars.
This study was partially funded by the NASA Astrobiology Program in collaboration with the University of Illinois at Chicago and the Desert Research Institute, a nonprofit research campus of the Nevada System of Higher Education.
For more information about DRI, visit:
Lake Vida, the largest of several unique lakes found in the McMurdo Dry Valleys, contains no oxygen, is mostly frozen and possesses the highest nitrous oxide levels of any natural water body on Earth. A briny liquid, which is approximately six times saltier than seawater, percolates throughout the icy environment where the average temperature is minus 8 degrees Fahrenheit. The international team of scientists published their findings online Nov. 26, in the Proceedings of the National Academy of Sciences Early Edition.
"This study provides a window into one of the most unique ecosystems on Earth," said Alison Murray, a molecular microbial ecologist and polar researcher at the DRI and the report's lead author. "Our knowledge of geochemical and microbial processes in lightless icy environments, especially at subzero temperatures, has been mostly unknown up until now. This work expands our understanding of the types of life that can survive in these isolated, cryoecosystems and how different strategies may be used to exist in such challenging environments."
Despite the very cold, dark and isolated nature of the habitat, the report finds the brine harbors a surprisingly diverse and abundant variety of bacteria that survive without a current source of energy from the sun. Previous studies of Lake Vida dating back to 1996 indicate the brine and its inhabitants have been isolated from outside influences for more than 3,000 years.
"This system is probably the best analog we have for possible ecosystems in the subsurface waters of Saturn's moon Enceladus and Jupiter's moon Europa," said Chris McKay, a senior scientist and co-author of the paper at NASA's Ames Research Center, Moffett Field, Calif.
Murray and her co-authors and collaborators, including Peter Doran, the project's principal investigator at the University of Illinois at Chicago, developed stringent protocols and specialized equipment for their 2005 and 2010 field campaigns to sample from the lake brine while avoiding contaminating the pristine ecosystem.
"The microbial ecosystem discovered at Lake Vida expands our knowledge of environmental limits for life and helps define new niches of habitability," said Adrian Ponce, co-author from NASA's Jet Propulsion Laboratory, Pasadena, Calif., who enumerated viable bacterial spore populations extracted from Lake Vida.
To sample unique environments such as this, researchers must work under secure, sterile tents on the lake's surface. The tents kept the site and equipment clean as researchers drilled ice cores, collected samples of the salty brine residing in the lake ice and assessed the chemical qualities of the water and its potential for harboring and sustaining life.
Geochemical analyses suggest chemical reactions between the brine and the underlying iron-rich sediments generate nitrous oxide and molecular hydrogen. The latter, in part, may provide the energy needed to support the brine's diverse microbial life.
Additional research is under way to analyze the abiotic, chemical interactions between the Lake Vida brine and its sediment, in addition to investigating the microbial community by using different genome sequencing approaches. The results could help explain the potential for life in other salty, cryogenic environments beyond Earth, such as purported subsurface aquifers on Mars.
This study was partially funded by the NASA Astrobiology Program in collaboration with the University of Illinois at Chicago and the Desert Research Institute, a nonprofit research campus of the Nevada System of Higher Education.
For more information about DRI, visit:
For more information about the NASA Astrobiology Program, visit:
Scanning electron micrograph of very small and numerous bacterial
cells inhabiting icy brine channels in Antarctica’s Lake Vida, which
lies in the Victoria Valley, one of the northernmost of the Antarctic
dry valleys.
Credit: Christian H. Fritsen, Desert Research Institute
Ancient Microbes Found Living Beneath the Icy Surface of Antarctic Lake
|
DRI scientists’ co-author study examining life in one of Earth’s coldest, ice-sealed ecosystems FOR IMMEDIATE RELEASE: November 26, 2012 RENO – This week a pioneering study published in the Proceedings of the National Academy of Science (PNAS) and co-authored by Dr. Alison Murray and Dr. Christian Fritsen of Nevada’s Desert Research Institute (DRI) reveals, for the first time, a viable community of bacteria that survives and ekes out a living in a dark, salty and subfreezing environment beneath nearly 20 meters of ice in one of Antarctica’s most isolated lakes.  Members of the Lake Vida expedition team.Enlarge image for caption.Lake Vida, the largest of several unique lakes found in the McMurdo Dry Valleys, contains no oxygen, is mostly frozen and possesses the highest nitrous oxide levels of any natural water body on Earth. A briny liquid that is approximately six times saltier than seawater percolates throughout the icy environment that has an average temperature of minus 13.5 degrees centigrade (or 8 degrees Fahrenheit). “This study provides a window into one of the most unique ecosystems on Earth,” said Murray, the report’s lead author, and molecular microbial ecologist and polar researcher for the past 17 years, who has participated in 14 expeditions to the Southern Ocean and Antarctic continent. “Our knowledge of geochemical and microbial processes in lightless icy environments, especially at subzero temperatures, has been mostly unknown up until now. This work expands our understanding of the types of life that can survive in these isolated, cryoecosystems and how different strategies may be used to exist in such challenging environments.”  Research field camp on Lake Vida, Victoria Valley. Enlarge image for caption.Despite the very cold, dark and isolated nature of the habitat, the report finds that the brine harbors a surprisingly diverse and abundant assemblage of bacteria that survive without a present-day source of energy from the sun. Previous studies of Lake Vida dating back to 1996 indicate that the brine and its’ inhabitants have been isolated from outside influences for more than 3,000 years. Murray and her co-authors and collaborators, including the project’s principal investigator Dr. Peter Doran of the University of Illinois at Chicago, developed stringent protocols and specialized equipment for their 2005 and 2010 field campaigns to sample the lake brine while avoiding contaminating the pristine ecosystem. To sample the unique environment researchers worked under secure, sterile tents on the lake’s surface to keep the site and equipment clean as they drilled ice cores, collected samples of the salty brine residing in the lake ice and then assessed the chemical qualities of the water and its potential for harboring and sustaining life, in addition to describing the diversity of the organisms detected. Bacterial cells inhabiting icy brine channels, Lake Vida. Enlarge photo for caption.Geochemical analyses suggest that chemical reactions between the brine and the underlying iron-rich sediments generate nitrous oxide and molecular hydrogen. The latter, in part, may provide the energy needed to support the brine’s diverse microbial life. “It’s plausible that a life-supporting energy source exists solely from the chemical reaction between anoxic salt water and the rock,” explained Fritsen, a systems microbial ecologist and Research Professor in DRI’s Division of Earth and Ecosystem Sciences. “If that’s the case,” echoed Murray. “This gives us an entirely new framework for thinking of how life can be supported in cryoecosystems on earth and in other icy worlds of the universe." Murray added further research is currently under way to analyze the abiotic, chemical interactions between the Lake Vida brine and the sediment, in addition to investigating the microbial community by using different genome sequencing approaches. The results could help explain the potential for life in other salty, cryogenic environments beyond Earth. The Lake Vida brine also represents a cryoecosystem that is a suitable and accessible analog for the soils, sediments, wetlands, and lakes underlying the Antarctic ice sheet that other polar researchers are just now beginning to explore. The funding for this research was supported jointly by NSF and NASA. About the Desert Research Institute:DRI, the nonprofit research campus of the Nevada System of Higher Education, strives to be the world leader in environmental sciences through the application of knowledge and technologies to improve people’s lives throughout Nevada and the world.All DRI news releases available at: http://news.dri.edu/ Additional Details:Proceedings of the National Academy of Science (PNAS)Article #12-08607 - “Microbial Life at -13 ºC in the Brine of an Ice-Sealed Antarctic Lake,” by Alison E. Murray et al. More information on the Lake Vida project can be found online at: http://www.dri.edu/lake-vida Photographs and Video available:Field Work – including the ice core drilling process, Antarctic expedition, ice cores, and Lake Vida research team members.
Link to full article: http://www.pnas.org/gca?submit=Get+All+Checked+Abstracts&gca=pnas%3B1208607109v1
|
Note to Reporters and Editors: DRI, the nonprofit research campus of
the Nevada System of Higher Education, strives to be the world leader in
environmental sciences through the application of knowledge and
technologies to improve people’s lives throughout Nevada and the world.
DRI News & Communications
|
Communications at DRI is the main contact for media relations. When
faculty members are contacted by the media, they are encouraged to
notify Communications for assistance. Communications is responsible for DRI's news releases, the DRI Newsletter and Magazine, and top-level content on the DRI website. Communications also assists the President's office with public relations, public events, development and marketing. Official DRI news releases are available below. |
|
Note to Reporters and Editors: DRI, the nonprofit research campus of the Nevada System of Higher Education, strives to be the world leader in environmental sciences through the application of knowledge and technologies to improve people’s lives throughout Nevada and the world.
NASA
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
No hay comentarios:
Publicar un comentario