Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New life beneath sea and ice

17.11.2008
Scientists have long known that life can exist in some very extreme environments. But Earth continues to surprise us.

At a European Science Foundation and COST (European Cooperation in the field of Scientific and Technical Research) 'Frontiers of Science' meeting in Sicily in October, scientists described apparently productive ecosystems in two places where life was not known before, under the Antarctic ice sheet, and above concentrated salt lakes beneath the Mediterranean. In both cases, innumerable tiny microbes are fixing or holding onto quantities of organic carbon large enough to be significant in the global carbon cycle.

Lakes under the ice

Brent Christner of Louisiana State University, in the US, told the conference about the microbes living within and beneath the ice on Antarctica. In the last decade, scientists have discovered lakes of liquid water underneath the Antarctic ice sheet. So far we know of about 150 lakes, but this number will probably increase when the entire continent has been surveyed. These lakes occur as a result of geothermal heat trapped by the thick ice, melting it from underneath, and the great pressure from the ice above, which lowers the melting point of water.

The largest subglacial lake, Lake Vostok, lies beneath the coldest place on the planet, where the temperature at the surface often falls below -60*C. "It's the sixth largest freshwater lake on the planet by volume, and about the size of Lake Ontario," says Christner. "If you were on a boat in the middle of the lake, you would not see shores."

Christner has examined microbial life in ice cores from Vostok and many other global locations. While direct samples of water from subglacial Antarctic lakes have yet to be obtained, the lower 80m or so of the Vostok ice core represents lake water that progressively freezes onto the base as the ice sheet slowly traverses the lake. "Microbial cell and organic carbon concentrations in this accreted ice are significantly higher than those in the overlying ice, which implies that the subglacial environment is the source," says Christner.

Based on accumulating measurements of microbes in the subglacial environment, he calculates that the concentration of cell and organic carbon in the Earth's ice sheets, or 'cryosphere', may be hundreds of times higher than what is found in all the planet's freshwater systems. "Glacial ice is not currently considered as a reservoir for organic carbon and biology," says Christner, "but that view has to change."

Salt below the sea

Beneath the Mediterranean lurks a similar surprise. Michail Yakimov of the Institute of the Coastal Marine Environment, Messina, Italy is a project leader for the European Science Foundation's EuroDEEP programme on ecosystem functions and biodiversity in the deep sea. His team studies lakes of concentrated salt solution, known as anoxic hypersaline basins, on the floor of the Mediterranean. They have discovered extremely diverse microbial communities on the surfaces of such lakes.

The anoxic basins, so called because they are devoid of oxygen, occur below 3,000 m beneath the surface and are five to ten times more saline than seawater. One theory says they exist uniquely in the Mediterranean, because this sea entirely evaporated after it was cut off from the Atlantic around 250 million years ago. Its salt became a layer of rock salt, called evaporite, which was then buried by windblown sediment. Now the sea is filled again, the salt layer has been exposed in some places, perhaps by small seaquakes, and the salts from the ancient Mediterranean have dissolved again, making the water very salty.

Despite the harsh conditions, hypersaline brines have been shown to possess a wide range of active microbial communities. Together with other international partners, Yakimov's team has already identified more than ten new lineages of bacteria and archaea (these are ancient bacteria-like organisms), which they have named the Mediterranean Sea Brine Lake Divisions.

There is ample life at the boundary between the concentrated basin and the ordinary seawater. "Because of the very high density of the brine, it does not mix with seawater," he explains, "and there is a sharp interface, about 1m thick."

In that layer, microbial diversity is incredibly rich. The research shows that these microbes largely live by sulphide oxidation. Like the communities at hydrothermal vents in the deep ocean, they can survive independently of sunlight and oxygen. But they are an important store for organic carbon. "The deep-sea microbial communities in the Mediterranean fix as much or even more carbon dioxide each year as those in the surface layers," says Yakimov. "This carbon sink should be taken into account at the global scale."

This research was presented at the "Complex Systems: Water and Life" Frontiers of Science conference, organized by European Science Foundation and COST, 29-31 October, Taormina, Sicily. http://www.esf.org/research-areas/life-earth-and-environmental-sciences/activities/lesc-cost-synergy.html.

Thomas Lau | alfa
Further information:
http://www.esf.org
http://www.esf.org/activities/eurocores/programmes/eurodeep.html

More articles from Earth Sciences:

nachricht NASA sees quick development of Hurricane Dora
27.06.2017 | NASA/Goddard Space Flight Center

nachricht Collapse of the European ice sheet caused chaos
27.06.2017 | CAGE - Center for Arctic Gas Hydrate, Climate and Environment

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>