A new research study to be published online in the journal Nature Geoscience have raised the question as to whether undersea methane is contributing to the rising acidification of the planet’s oceans.
The research team found methane leaking from “cold seeps” in two areas of the Pacific Ocean was being taken up by oceanic microorganisms and bacteria as dissolved organic carbon, or DOC, a byproduct of which is carbon dioxide which in large enough quantities increases the acidity of the water.
“Normally, DOC primarily comes from the degradation of phytoplankton (algae), or from river discharge into the ocean,” says Dr. Chris Osburn, assistant professor of marine science at NC State and member of the research team led by geologists from the U.S. Geological Survey. “Finding DOC that comes from methane is a new part of the carbon cycle that hasn’t really been accounted for.”
Finding methane in two cold seeps does not mean it is everywhere, and the researchers will look to cold seeps worldwide to see if it is localised phenomenon.
“Based on what we found, up to 30 percent of the Pacific Ocean’s deep water DOC could be methane-derived,” Osburn says. “If it is utilized by marine microorganisms, methane-derived DOC could be a component of deep ocean ecosystems. Moreover, microbial processing of this DOC could be contributing to increased CO2 in the deep ocean and thus to ocean acidification.”
Source: North Carolina State University