Methane-munching, rock-dwelling microbes in deep ocean may be our best bet against global warming


The Earth's warming climate has raised alarm because of its devastating impact but it appears that there are organisms in the sea that help in humanity's fight against global warming.

In a new study, researchers claimed that a group of methane-munching microbes that live in rocky dwellings on the seafloor could be preventing large amounts of greenhouse gas from reaching the surface of the ocean and the atmosphere, where it could contribute to rising global temperatures.

Heat-trapping greenhouse gases are attributed as a major contributor to climate change that the world experiences today and whose effects range from rising sea levels to potentially fueling international conflict.

Although most focus has been centered on carbon dioxide because it is more abundant and thus contributes more to global warming, methane is about 30 percent more powerful than carbon dioxide when it comes to trapping heat. Fortunately, an army of microbes appear to curb levels of this greenhouse gas.

Jeffrey Marlow, from the Division of Geological and Planetary Sciences at the California Institute of Technology, and colleagues have found that the towering rocks lying at the ocean floor and near methane seeps, are the dwellings of methane-munching microbes.

For their study, the researchers examined 24 rock samples from under the sea that were from near active methane seeps and from areas without methane activity and found that the rocks from near the methane seeps have clusters of microbes inside them. Further investigation revealed that these microbes consume methane and they excrete byproducts that mineralize and form into the towering rocks.

"Here we show that seep-associated carbonates harbour active microbial communities, serving as dynamic methane sinks," the researchers wrote in their study. "Carbonate-hosted methanotrophy represents an unrecognized methane sink in the deep sea," which was published in the Nature Communications on Oct. 14.

The findings reveal the important role played by these microbes as they consume enough methane to influence the global levels of greenhouse gas. Between 6 and 22 percent of the Earth's methane comes from seeps in the ocean floor but most of these do not get into the surface nor released into the atmosphere because microbes consume up to 90 percent of this.

"Without this biological process, much of that methane would enter the water column, and the escape rates into the atmosphere would probably be quite a bit higher," Marlow said. "There are likely many more microbes living in carbonate mounds than in sediments, their contributions to methane removal from the environment may be more significant." 

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