image: Assistant professor of biochemistry and Fralin Life Sciences Institute affiliate Kylie Allen researches methanogens in her lab in Engel Hall. view more
Credit: Kristin Rose Jutras for Virginia Tech
Carbon is the building block of all known life on our planet. The carbon cycle regulates the release and absorption of carbon from a number of natural sources — including the ocean, soil, geochemical processes, and human emissions — to maintain a delicate balance of this crucial element in our world.
An increase in carbon dioxide and methane in the atmosphere is partly responsible for the adverse effects of climate change experienced in Virginia and throughout the world.
New research at Virginia Tech, the University of Bremen, and the Max Planck Institute for Marine Microbiology has revealed that two kinds of microorganisms - methanogens and anaerobic methanotrophs – are able to produce a form of elemental carbon known as amorphous carbon.
For researchers who study methanogens and anaerobic methanotrophs, the discovery defies all previous expectations of what microorganisms can do, and sheds scientific light on some very interesting questions.
Why and how are these microorganisms making amorphous carbon? Is amorphous carbon being produced in large enough quantities to affect the carbon cycle on Earth?
“We never thought that amorphous carbon could be produced by living organisms because of the normally extreme chemical reactions that are needed to form it,” said Robert White, an emeritus professor of biochemistry in the College of Agriculture and Life Sciences. “This is the first report of amorphous carbon being produced by any organism on Earth, and we are very interested in the possible implications it may have for the carbon cycle.”
Their findings were published in the American Association for the Advancement of Science's open access multidisciplinary journal, Science Advances.
Amorphous carbon is a form of elemental carbon that lacks the hard, crystalline structure of graphite or diamond. The substance is usually formed under extreme temperatures and pressures, or during the burning of organic matter.
One place where amorphous carbon can be found is in your fireplace in the winter. When you burn firewood, the intensity of the heat creates a reaction that disintegrates the wood and leaves behind an ashy, black soot. That residual substance contains amorphous carbon.
Methanogens, or methane-producing microorganisms, have long piqued the interest of scientists because of their role in producing and releasing methane, a potent greenhouse gas, into the environment.
The microorganisms thrive in areas with high amounts of decayed organic matter and low-oxygen, such as wetlands, landfills, and cow stomachs. As these microorganisms eat the breakdown products of organic matter, they produce methane.
The methane produced by these methanogens accounts for 90 percent of biologically produced methane, with 31 percent of this coming from cows alone.
Over the years, methanogen researchers have noticed little black specks forming inside their bacterial cultures during experiments. They had hypothesized that the specks were iron sulfide, another black material that is commonly formed in methanogenic growth media.
In other experiments with anaerobic methanotrophs, researchers found even more black material. Anaerobic methanotrophs are microorganisms that also thrive in the low-oxygen areas, but instead prefer the ocean floor. As they consume the methane that is seeping from the ocean floor, they convert it into carbon dioxide.
"I've always wondered, as have a number of other methanogen experts, what this black material is,” said Kylie Allen, the lead author on the study and an assistant professor of biochemistry in the College of Agriculture and Life Sciences and affiliate faculty of the Fralin Life Sciences Institute. “We used to think it was iron sulfide deposits in methanogenic cultures, but anaerobic methanotrophs produce far more of this black stuff.”
Overwhelmed with curiosity, a few methanogen researchers from across the world banded together and began to take a deeper, more analytical dive into these mysterious specks.
Carbon is the building block of all known life on our planet. The carbon cycle regulates the release and absorption of carbon from a number of natural sources — including the ocean, soil, geochemical processes, and human emissions — to maintain a delicate balance of this crucial element in our world.
An increase in carbon dioxide and methane in the atmosphere is partly responsible for the adverse effects of climate change experienced in Virginia and throughout the world.
New research at Virginia Tech, the University of Bremen, and the Max Planck Institute for Marine Microbiology has revealed that two kinds of microorganisms - methanogens and anaerobic methanotrophs – are able to produce a form of elemental carbon known as amorphous carbon.
For researchers who study methanogens and anaerobic methanotrophs, the discovery defies all previous expectations of what microorganisms can do, and sheds scientific light on some very interesting questions.
Why and how are these microorganisms making amorphous carbon? Is amorphous carbon being produced in large enough quantities to affect the carbon cycle on Earth?
“We never thought that amorphous carbon could be produced by living organisms because of the normally extreme chemical reactions that are needed to form it,” said Robert White, an emeritus professor of biochemistry in the College of Agriculture and Life Sciences. “This is the first report of amorphous carbon being produced by any organism on Earth, and we are very interested in the possible implications it may have for the carbon cycle.”
Their findings were published in the American Association for the Advancement of Science's open access multidisciplinary journal, Science Advances.
Amorphous carbon is a form of elemental carbon that lacks the hard, crystalline structure of graphite or diamond. The substance is usually formed under extreme temperatures and pressures, or during the burning of organic matter.
One place where amorphous carbon can be found is in your fireplace in the winter. When you burn firewood, the intensity of the heat creates a reaction that disintegrates the wood and leaves behind an ashy, black soot. That residual substance contains amorphous carbon.
Methanogens, or methane-producing microorganisms, have long piqued the interest of scientists because of their role in producing and releasing methane, a potent greenhouse gas, into the environment.
The microorganisms thrive in areas with high amounts of decayed organic matter and low-oxygen, such as wetlands, landfills, and cow stomachs. As these microorganisms eat the breakdown products of organic matter, they produce methane.
The methane produced by these methanogens accounts for 90 percent of biologically produced methane, with 31 percent of this coming from cows alone.
Over the years, methanogen researchers have noticed little black specks forming inside their bacterial cultures during experiments. They had hypothesized that the specks were iron sulfide, another black material that is commonly formed in methanogenic growth media.
In other experiments with anaerobic methanotrophs, researchers found even more black material. Anaerobic methanotrophs are microorganisms that also thrive in the low-oxygen areas, but instead prefer the ocean floor. As they consume the methane that is seeping from the ocean floor, they convert it into carbon dioxide.
"I've always wondered, as have a number of other methanogen experts, what this black material is,” said Kylie Allen, the lead author on the study and an assistant professor of biochemistry in the College of Agriculture and Life Sciences and affiliate faculty of the Fralin Life Sciences Institute. “We used to think it was iron sulfide deposits in methanogenic cultures, but anaerobic methanotrophs produce far more of this black stuff.”
Overwhelmed with curiosity, a few methanogen researchers from across the world banded together and began to take a deeper, more analytical dive into these mysterious specks.
Journal
Science Advances