Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists unravel the mystery of marine methane oxidation

13.11.2012
Researchers uncover how microorganisms on the ocean floor protect the atmosphere against methane

Microbiologists and geochemists from the Max Planck Institute for Marine Microbiology, along with their colleagues from Vienna and Mainz, show that marine methane oxidation coupled to sulfate respiration can be performed by a single microorganism, a member of the ancient kingdom of the Archaea, and does not need to be carried out in collaboration with a bacterium, as previously thought. They published their discovery as an article in the renowned scientific journal Nature.


The enrichment of the microorganisms responsible for marine AOM, archaea in red and bacteria in green from the Isis Mud Volcano in the Mediterranean Sea has taken 8 years of continuous incubation. Without these cultures it would not have been possible to trace down the complex sulfur cycling involved in AOM.

© Jana Milucka, MPI f. Marine Microbiology


In this model, methane oxidation and sulfate respiration to elemental sulfur (or all the way to sulfide) is performed by the methanotrophic archaea (ANME). The associated bacteria (DSS) are disproportionators (sulfur fermentors), which take up produced elemental sulfur in the form of disulfide and turn it into sulfate and sulfide. Dark circles represent iron- and phosphorus-rich precipitates found in the bacteria.

© Jana Milucka, MPI f. Marine Microbiology

Vast amounts of methane are stored under the ocean floor. Anaerobic oxidation of methane coupled to sulfate respiration (AOM) prevents the release of this potent greenhouse gas into the atmosphere. Although the process was discovered 35 years ago it has remained a long standing mystery as to how microorganisms perform this reaction. A decade ago, an important discovery was made which showed that two different microorganisms are often associated with AOM. It was proposed that these two microorganisms perform different parts of the AOM reaction. One, an archaeon, was supposed to oxidize methane and the other, a bacterium, was supposed to respire sulfate. This implied the existence of an intermediate compound to be shuttled from the methane oxidizer to the sulfate respirer.

Now, the team around Professor Kuypers has turned this whole model on its head. They show that the archaeon not only oxidizes methane but can also respire sulfate and does not necessarily need the bacterial partner. It appears that the archaeon does not employ the common enzyme toolbox that other known sulfate-respiring microorganisms use, but relies on a different, unknown pathway.

The basis for this dramatic shift in thinking is the observation that elemental sulfur is formed and accumulates in the methane-oxidizing archaeon. “Using chromatographic and state-of-the-art spectroscopic techniques we found surprisingly high concentrations of elemental sulfur in our cultures”, says Professor Marcel Kuypers and adds: “The single-cell techniques showed that the sulfur content in the methane-degrading archaeon was much higher than in the bacterium. Our experiments show that this sulfur is formed during sulfate respiration.”
This finding begs the question: What does the bacterium do if the archaeon does both sulfate respiration and methane oxidation? “The bacteria actually make a living off of the elemental sulfur produced by the archaea”, explains Jana Milucka, first author of the study. “The bacteria grow by splitting the elemental sulfur into sulfate and hydrogen sulfide. This is a form of fermentation, like the process that produces alcohol.”

“Until now we have always had trouble explaining the occurrence of elemental sulfur in oxygen-free sediments”, notes Tim Ferdelman, scientist at the MPI Bremen and coauthor on the publication. ”Our discoveries not only provide a mechanism for marine methane oxidation but also cast a new light on the carbon and sulfur cycling in marine, methane-rich sediments.”

Contact

Dr. Marcel Kuypers
Max Planck Institute for Marine Microbiology, Bremen
Phone: +49 421 2028-602
Fax: +49 421 2028-690
Email: mkuypers@­mpi-bremen.de
Dr. Rita Dunker
Max Planck Institute for Marine Microbiology, Bremen
Phone: +49 421 2028-856
Fax: +49 421 2028-790
Email: rdunker@­mpi-bremen.de
Dr. Manfred Schlösser
Press Officer
Max Planck Institute for Marine Microbiology, Bremen
Phone: +49 4 212028-704
Email: mschloes@­mpi-bremen.de

Original publication
Jana Milucka, Timothy G. Ferdelman, Lubos Polerecky, Daniela Franzke, Gunter Wegener, Markus Schmid, Ingo Lieberwirth, Michael Wagner, Friedrich Widdel, Marcel M. M. Kuypers
Zerovalent sulfur is a key intermediate in marine methane oxidation
Nature, 2012. 8 November, 2012. Doi: 10.1038/nature11656

Dr. Marcel Kuypers | Max-Planck-Institut
Further information:
http://www.mpg.de/6619070/marine-methane-oxidation

More articles from Life Sciences:

nachricht Molecular microscopy illuminates molecular motor motion
26.07.2017 | Penn State

nachricht New virus discovered in migratory bird in Rio Grande do Sul, Brazil
26.07.2017 | Fundação de Amparo à Pesquisa do Estado de São Paulo

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

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

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

CCNY physicists master unexplored electron property

26.07.2017 | Physics and Astronomy

Molecular microscopy illuminates molecular motor motion

26.07.2017 | Life Sciences

Large-Mouthed Fish Was Top Predator After Mass Extinction

26.07.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>