Cinder cones from underwater volcanoes have become a source of greenhouse gases. The reason for this is not yet known to scientists.
Scientists from Oregon State University have confirmed evidence of the first active methane leak from the Antarctic seafloor. The phenomenon was discovered in the cinder cones of underwater volcanoes during research work in McMurdo Sound. An article about this was published in the Proceedings of the Royal Society B.
Experts have long assumed that large amounts of methane accumulate in the bottom region of the so-called Southern Ocean. Its main source may be decomposing algae. As global warming warms the waters, the gas can rise up and enter the atmosphere, warming it even more.
However, in the case under consideration, the methane release was not recorded in the part of the ocean that is significantly warming, so the cause of this leak is a mystery to scientists. Researchers are also very concerned about the reaction of marine methanotrophic microorganisms. Usually, when methane was noticeably released in the bottom region, bacteria began to actively utilize it, preventing the gas from rising to the surface, but this does not happen in the cinder cones of McMurdo Sound: although the first reports of methane accumulating at the bottom appeared nine years ago, the activity of methanotrophic microorganisms changed very slowly at the location.
Analyzes of microbial RNA in seawater samples showed that bacteria capable of utilizing methane make up only a few percent of the total microflora at the site of the gas release. "It is bad news. It took more than five years for microbes to emerge [in sufficient quantities of the cinder cones], and even then methane continued to rise rapidly from the seafloor,” says study co-author Andrew Tharber.
An increase in the concentration of methane in the atmosphere will strengthen the greenhouse effect and lead to a more intense increase in temperature on Earth. As follows from the report of the International Panel on Climate Change, published in 2014, over a 100-year period, the greenhouse activity of methane is 28 times stronger than that of carbon dioxide, and over a 20-year period – 84 times.