Researchers have discovered that deep-sea bacteria dissolve carbon-containing rocks, releasing carbon into the ocean and atmosphere.
Researchers made the discovery when they studied sulfur-oxidising bacteria in methane seeps on the ocean floor at the Del Mar East Methane Seep Field, USA. These seeps contain collections of limestone that trap large amounts of carbon.
They then observed that in the process of oxidising sulfur, the bacteria creates an acidic reaction that dissolves the rocks and this causes the carbon trapped inside the limestone to be released.
Their findings was published in the The ISME Journal: Multidisciplinary Journal of Microbial Ecology.
"If CO2 is being released into the ocean, it's also being released into the atmosphere, because they're constantly interchanging gases between them," said Dalton Leprich, the first author and a PhD student in the University of Minnesota's Department of Earth and Environmental Sciences.
"While it's not as big of an impact as what humans are doing to the environment, it is a flux of CO2 into the atmosphere that we didn't know about. These numbers should help us hone in on that global carbon budget."
The team intend to extend their research to different mineral types. It is hoped that their findings will facilitate better estimates of the amount of carbon dioxide in the Earth’s atmosphere.
"These findings are but one of the many examples of the important and understudied role that microbes play in mediating the cycling of elements on our planet," said corresponding author Jake Bailey, an associate professor at the University's Department of Earth and Environmental Sciences.