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

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>