Scientists have found the cause of the greenhouse effect

Up to four percent of methane on Earth comes from oxygen-rich ocean water, but scientists have until recently been unable to determine the specific source of this greenhouse gas. Now the researchers claim that they managed to find it.

The scientists who made the discovery did not set themselves the task of investigating the geochemistry of the ocean. They were looking for new antibiotics. Funded by the National Institute of Health, the project investigated an unusual class of potential antibiotics called phosphonates, which are already used in agriculture and medicine.

"We are studying all kinds of antibiotics that have carbon-phosphorus bonds," explains the professor of microbiology William Metcalf of the University of Illinois (project manager) and Professor Wilfred van der Donck of the Institute of Genomic Biology. "We managed to find genes from microbes, which, in our opinion, were supposed to produce an antibiotic. But they did not. They did something completely different. "

This microbe was Nitrosopumilus maritimus, one of the most common organisms on the planet, an inhabitant of the oxygen-rich waters of the open ocean. In these microbes, scientists have found genes that, presumably, could produce potential antibiotics - phosphonic acids. Taking the necessary DNA fragment of Nitrosopumilus maritimus, the researchers transferred its copies to the genome of Escherichia coli (E. Coli), but this modified bacterium began to produce not an antibiotic, as the scientists hoped, but methylphosphonic acid (methylphosphonate).

This substance was used by researchers to confirm the previously unpopular hypothesis that methane in the ocean is a product of the life of bacteria that split methyl phosphonate into methane and phosphoric acid.

"There was only one problem with this theory," says van der Donck. - Methylphosphonic acid has never before been found in marine ecosystems. Based on known chemical reactions, it was difficult to understand how this compound can be produced without the use of unusual biochemistry. "

Growing Nitrosopumilus maritimus in laboratory conditions in large quantities together with other bacteria, the habitat of which is the ocean, scientists have discovered that methylphosphonate accumulates in the walls of Nitrosopumilus maritimus cells. After the death of this microorganism, other bacteria tear apart the carbon-phosphorus bond of the methylphosphonate to devour the phosphorus element, which is rare in the oceans, but necessary for life. Thus, if a carbon-phosphorus bond is broken in the methylphosphonate, methane is also released.

Scientists note that their discovery will allow us to better understand the nature of climate change on the planet.

"We know that twenty percent of the greenhouse effect depends on methane, four percent of which comes from a previously unknown source. You need to know where methane is produced and what happens to it to understand what will happen when the climate changes, "said William Metcalfe.

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