Chloe Tenn graduated from North Carolina State University, where she studied neurobiology, English, and forensics. She is fascinated by the intersection of science and society, for...

Learn about our editorial policy.

Above: Amorphous carbon (black) in a culture of anaerobic methanotrophs (amber) GUNTER WEGENER

An international team of scientists claimed to have identified two deep-sea microbial communities that produce amorphous carbon, an elemental carbon. Robert White, a biochemist and co-author of the paper at Virginia Tech, said in a press release: “This is the first report of any organism on the planet that produces amorphous carbon, adding that the team is Very interested in the possible impact. "cycle."

"We never thought that living organisms can produce amorphous carbon, because it usually requires extreme chemical reactions to form it," he added.

Compared with life-related molecules, elemental carbon contains only carbon atoms, where carbon is connected to other elements such as hydrogen and oxygen. It exists in many different forms, from crystalline diamond formed under high pressure and high temperature to black powdery amorphous carbon in soot. According to "Chemical World", its synthesis is non-biological under all previously known conditions. But a paper published in Science Advances on October 27 described elemental carbon produced by microorganisms cultivated in deep-sea sediments. 

These microorganisms were originally collected between 2003 and 2009 and cultivated for several years to gain a deeper understanding of the biochemical processes of organisms living in the deep ocean. There are two members of the microbiota in the organisms studied: methanogens, which produce methane instead of carbon dioxide during respiration, and anaerobic methane-oxidizing bacteria, which consume methane as a carbon source. Both thrive in low-oxygen environments, such as hydrothermal vents in the Gulf of California and deep-sea mud volcanoes in the Mediterranean, where researchers obtain research samples.

When they were cultivating microorganisms, they noticed that these creatures produced black spots, which they initially thought might be metal deposits. However, Raman spectroscopy showed that the material was pure carbon, and subsequent analysis confirmed this finding.

The lead author and Virginia Tech biochemist Kelly Allen pointed out in the university's announcement that it is not yet clear why these organisms produce amorphous carbon. They may synthesize it directly for some purpose, or as a by-product of an important process; "We don't know which one it is. This is what we really want to figure out in the future," she said.

The authors of the paper believe that amorphous carbon can play a role in protecting microorganisms from toxins, or as a conductive element for electron transfer. "Elemental carbon is a good electrical conductor. Carbon may be the key to symbiosis between archaea and their partners," co-author and marine microbiologist Gunter Wegener hypothesized in a press release from the University of Bremen.

"It is not at all clear how much elemental carbon is formed by microorganisms in nature and where it resides," he pointed out in a press release from Virginia Tech.

Answering questions about the nature and amount of carbon produced can help clarify whether these organisms have a significant impact on the global carbon cycle. Considering the relatively inactive nature of amorphous carbon and the location of these microorganisms on the seafloor, most of the carbon they produce may remain deep in the ocean and act as a carbon sink. However, Allen emphasized that there is still a long way to go to draw any conclusions of this nature.

© 1986–2021 Scientist. all rights reserved.