Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Siberian hot springs reveal ancient ecology

27.04.2011
Geochemist Albert Colman follows trail from Kamchatka microbes into the history of Earth’s atmosphere.

Exotic bacteria that do not rely on oxygen may have played an important role in determining the composition of Earth’s early atmosphere, according to a theory that UChicago researcher Albert Colman is testing in the scalding hot springs of a volcanic crater in Siberia.

He has found that bacteria at the site produce as well as consume carbon monoxide, a surprising twist that scientists must take into account as they attempt to reconstruct the evolution of Earth’s early atmosphere.

Colman, an assistant professor in geophysical sciences, joined an American-Russian team in 2005 working in the Uzon Caldera of eastern Siberia’s Kamchatka Peninsula to study the microbiology and geochemistry of the region’s hot springs. Colman and his colleagues focused on anaerobic carboxydotrophs — microbes with a physiology as exotic as their name. They use carbon monoxide mostly for energy, but also as a source of carbon for the production of new cellular material.

This carbon monoxide-based physiology results in the microbial production of hydrogen, a component of certain alternative fuels. The research team thus also sought to probe biotechnological applications for cleaning carbon monoxide from certain industrial waste gases and for biohydrogen production.

“We targeted geothermal fields,” Colman says, “believing that such environments would prove to be prime habitat for carboxydotrophs due to the venting of chemically reduced, or in other words, oxygen-free and methane-, hydrogen-, and carbon dioxide-rich volcanic gases in the springs.”

The team did discover a wide range of carboxydotrophs. Paradoxically, Colman found that much of the carbon monoxide at the Kamchatka site was not bubbling up with the volcanic gases; instead “it was being produced by the microbial community in these springs,” he says. His team began considering the implications of a strong microbial source of carbon monoxide, both in the local springs but also for the early Earth.

The Great Oxidation Event
Earth’s early atmosphere contained hardly any oxygen but relatively large amounts of carbon dioxide and possibly methane, experts believe. Then during the so-called Great Oxidation Event about 2.3 to 2.5 billion years ago, oxygen levels in the atmosphere rose from vanishingly small amounts to modestly low concentrations.

“This important transition enabled a widespread diversification and proliferation of metabolic strategies and paved the way for a much later climb in oxygen to levels that were high enough to support animal life,” Colman says.

The processing of carbon monoxide by the microbial community could have influenced atmospheric chemistry and climate during the Archean, an interval of Earth’s history that preceded the Great Oxidation Event.

Previous computer simulations rely on a primitive biosphere as the sole means of removing near-surface carbon monoxide produced when the sun’s ultraviolet rays split carbon dioxide molecules. This theoretical sink in the biosphere would have prevented substantial accumulation of atmospheric carbon monoxide.

“But our work is showing that you can’t consider microbial communities as a one-way sink for carbon monoxide,” Colman says. The communities both produce and consume carbon monoxide. “It’s a dynamic cycle.”

Colman’s calculations suggest that carbon monoxide may have nearly reached percentage concentrations of 1 percent in the atmosphere, tens of thousands of times higher than current concentrations. This in turn would have exerted influence on concentration of atmospheric methane, a powerful greenhouse gas, with consequences for global temperatures.

Toxic Concentrations
Furthermore, such high carbon monoxide concentrations would have been toxic for many microorganisms, placing evolutionary pressure on the early biosphere.

“A much larger fraction of the microbial community would’ve been exposed to higher carbon monoxide concentrations and would’ve had to develop strategies for coping with the high concentrations because of their toxicity,” Colman says.

Colman and UChicago graduate student Bo He have conducted fieldwork in both Uzon and California’s Lassen Volcanic National Park. Colman has most recently journeyed to Kamchatka for additional fieldwork in 2007 and 2010.

“This fantastic field site has a wide variety of hot springs,” he says. “Different colors, temperatures, chemistries, different types of micro-organisms living in them. It’s a lot like Yellowstone in certain respects.” Lassen’s springs have a narrower range of acidic chemistries, yet microbial production of carbon monoxide appears to be widespread in both settings.

Collaborator Frank Robb of the University of Maryland, Baltimore, lauds Colman for his “boundless enthusiasm” and for his “meticulous preparation,” much-needed qualities to ensure the safe transport of delicate instruments into the field.

Some of the microbial life within the caldera’s complex hydrothermal system may survive in even more extreme settings than scientists have observed at the surface, Colman says. “One thing we really don’t know very well is the extent to which microbial communities beneath the surface influence what we see at the surface, but that’s possible as well,” Colman says. “We know from culturing deep-sea vent microbes that they can live at temperatures that exceed the temperatures we’re observing right at the surface, and some of the turn out to metabolize carbon monoxide.”

The National Science Foundation and the National Aeronautics and Space Administration’s Astrobiology Institute have funded Colman’s Kamchatka research. The work offers insights into astrobiology, the study of the potential for life on other worlds, by showing how organisms might thrive in extreme environments beyond Earth, including the subsurface of Mars, Jupiter’s moon Europa, or even planets orbiting other stars.

By Steve Koppes

Steve Koppes | EurekAlert!
Further information:
http://www.uchicago.edu

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

NASA laser communications to provide Orion faster connections

30.03.2017 | Physics and Astronomy

Reusable carbon nanotubes could be the water filter of the future, says RIT study

30.03.2017 | Studies and Analyses

Unique genome architectures after fertilisation in single-cell embryos

30.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>