Seabed microbes munch methane, curb warming -study
Source: Reuters
By Alister Doyle, Environment Correspondent OSLO, Oct 18 (Reuters) - Exotic microbes living around mud volcanoes on the seabed are helping to offset global warming by munching heat-trapping methane seeping from the depths, scientists said on Wednesday. They said the microbes, studied at a mud volcano on the floor of the Arctic Barents Sea between Greenland and Norway, were part of fragile habitats that could also hold industrial clues about how to convert methane into more easily used fuels. "Methane-consuming microbes ... are helping to control climate change," the journal Nature said of the report it published by scientists at German and French institutes. Microbes around the Haakon Mosby Mud Volcano are a pinprick in offsetting climate change by consuming thousands of tonnes of methane, the main component of natural gas and which is also a powerful greenhouse gas. The scientists found a new methane-consuming microbe -- an oxygen-hating type of single-celled archaea dubbed ANME-3 -- living alongside two other known types of microbes by the mud volcano in waters 1,250 metres (4,100 ft) deep. "Finding a new type of microbe is important to help understand the methane cycle," said Antje Boetius, an author of the study who runs a laboratory at the Max Planck Institute for Marine Microbiology in Germany. Scientists have known about such methane-consuming microbes for less than a decade and have no reliable estimates of world methane emissions from subsea vents, she told Reuters. BACTERIA, WORMS The study, the first description of a subsea mud volcano habitat including archaea, bacteria and tube worms, found the microbes were able to consume less than 40 percent of methane emitted because they thrived only in a thin layer of mud. "They have enough to eat but they suffocate elsewhere," Boetius said. The microbes lived only where they could get both nutrients from the sea and methane from the volcano. She added that the findings might help unravel how methane-munching microbes work and give clues about how to convert the gas into a more easily transported liquid. "Industry is interested into converting methane into another energy-rich molecule, such as methanol or butane. Industrialists can do it chemically but they are hoping for a microbe that could do it much more efficiently," she said. Boetius said it would cost far too much to trap methane from most subsea vents. In California, however, methane bubbling from the seabed near Santa Barbara is trapped by tent-like metal structures, providing energy for almost 200 homes. Scientists have found thousands of mud volcanoes around the world, on land and on the seabed, spewing out sediments and gases through vents blown open by high pressure deep below the surface. Such volcanoes do not produce red-hot lava. In Java, Indonesia, a mud volcano erupted in May and has since flooded an area larger than Monaco, displacing more than 10,000 people from swamped homes. Methane is about 21 times more powerful as a greenhouse gas than carbon dioxide, released mainly by burning fossil fuels. Many scientists predict more powerful storms, heatwaves, droughts and rising seas by 2100 because of warming.
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