Deep sea methane scavengers capturedMay 14, 2008Leipzig / Pasadena. Scientists of the Helmholtz Centre for Environmental Research (UFZ) in Leipzig and the California Institute of Technology (Caltech) in Pasadena succeeded in capturing syntrophic (means "feeding together") microorganisms that are known to dramatically reduce the oceanic emission of methane into the atmosphere. These microorganisms that oxidize methane anaerobically are an important component of the global carbon cycle and a major sink for methane on Earth. Methane -- a more than 20 times stronger greenhouse gas than carbon dioxide -- constantly seeps out large methane hydrate reservoirs in the ocean floors, but 80 percent of it are immediately consumed by these microorganisms. The importance of the anaerobic oxidation of methane for the Earth's climate is known since 1999 and various international research groups work on isolating the responsible microorganisms, so far with little success. Pernthaler and co-workers developed a new molecular technique to selectively separate these microorganisms from their natural complex community, and subsequently sequenced their genome. The findings were exciting: Besides identifying all genes responsible for the anaerobic oxidation of methane, new bacterial partners of this syntrophic association were discovered and the ability to fix N2 could be demonstrated. The work has been published in the current issue of the renowned Journal Proceedings of the National Academy of Sciences (PNAS). The beauty of small things revealed Microorganisms are the unseen majority on our planet: There are more than 100 Million times more microbial cells than stars in the visible universe, accounting for more than 90 percent of the Earth's biomass. Yet, we have little idea what most of these bacteria and archaea are doing. It is not only their small size that makes them hard to study. Most microorganisms can not be grown, and thus studied, in the lab. But recent developments of new molecular techniques allow the study of microorganisms where they live: In nature. This is leading to an explosion of knowledge with no end in sight. One of these techniques is genome sequencing - learning about the genetic make-up of an organism. This works well for single organisms, such as the sequencing of the human genome. The complexity of natural microbial communities, however, is a major problem. The vast collection of genes can often not be linked to an organism or a physiological process. This plenitude of general information can be compared to a one-billion pieces puzzle of which you own only 300 pieces and you have to try to find out where which piece belongs and how the whole picture could look like. Scientist at UFZ and Caltech now developed a method that solves this problem. Pernthaler and co-workers attached small ironbeads to the microorganisms of interest and pulled them out of the deep sea sediment by simply applying a magnet. These microbes are Archaea, which cooperate with sulfate reducing Bacteria to perform a thermodynamically tricky process: the anaerobic oxidation of methane (AOM). These poorly understood consortia are globally distributed in oceanic sediments above methane hydrates and provide a significant sink for methane by substantially reducing the export of this potent greenhouse gas into the atmosphere. After sequencing the genomes of the purified syntrophic consortia, Pernthaler and co-workers could find all genes responsible for AOM. The scientist also discovered an unexpected diversity in the bacterial partners of this syntrophic association, which may play a role in the performance of AOM. Pernthaler and co-workers also found genes for N2 fixation and demonstrated in lab experiments that the AOM archaea are indeed fixing N2. These results are intriguing, especially since the fixation of N2 is energetically expensive processes and the energy gained by AOM is low. The potential for metabolic versatility combined with the ability to form partnerships with other microorganisms, might be the secret to the successful distribution of this biogeochemically significant group of microorganisms. This work is being published in PNAS, May 13th, 2008, the method has been patented (Pernthaler A, Orphan VJ (2007) US Patent 11/746,374). Helmholtz Association of German Research Centres |
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| Related Methane Current Events and Methane News Articles Interactions with aerosols boost warming potential of some gases For decades, climate scientists have worked to identify and measure key substances -- notably greenhouse gases and aerosol particles -- that affect Earth's climate. Report examines hidden costs of energy production and use A new report from the National Research Council examines and, when possible, estimates "hidden" costs of energy production and use -- such as the damage air pollution imposes on human health -- that are not reflected in market prices of coal, oil, other energy sources, or the electricity and gasoline produced from them. Caltech researchers reveal unexpected sources of nitrogen fixation Researchers at the California Institute of Technology (Caltech) have identified an unexpected metabolic ability within a symbiotic community of microorganisms that may help solve a lingering mystery about the world's nitrogen-cycling budget. Arctic land and seas account for up to 25 percent of world's carbon sink In a new study in the journal Ecological Monographs, ecologists estimate that Arctic lands and oceans are responsible for up to 25 percent of the global net sink of atmospheric carbon dioxide. Coal-mining hazard resembles explosive volcanic eruption, study shows Worldwide, thousands of workers die every year from mining accidents, and instantaneous coal outbursts in underground mines are among the major killers. But although scientists have been investigating coal outbursts for more than 150 years, the precise mechanism is still unknown. Mystery Solved: Marine Microbe Is Source of Rare Nutrient A new study of microscopic marine microbes, called phytoplankton, by researchers at Woods Hole Oceanographic Institution (WHOI) and the University of South Carolina has solved a ten-year-old mystery about the source of an essential nutrient in the ocean. Denver to Barcelona: Global cities and greenhouse gas emissions Denver released the largest amount of greenhouse gases (GHG) and Barcelona the smallest amount in a new study documenting how differences in climate, population density and other factors affect GHG emissions in global cities. Carnegie Institution The future of the Earth could rest on potentially dangerous and unproven geoengineering technologies unless emissions of carbon dioxide can be greatly reduced, a new study has found. International Greenland ice coring effort sets new drilling record in 2009 A new international research effort on the Greenland ice sheet with the University of Colorado at Boulder as the lead U.S. institution set a record for single-season deep ice-core drilling this summer, recovering more than a mile of ice core that is expected to help scientists better assess the risks of abrupt climate change in the future. Stressed crops emit more methane than thought Scientists at the University of Calgary have found that methane emission by plants could be a bigger problem in global warming than previously thought. More Methane Current Events and Methane News Articles |
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