University of Tennessee study: Unexpected microbes fighting harmful greenhouse gas

November 21, 2012

The environment has a more formidable opponent than carbon dioxide. Another greenhouse gas, nitrous oxide, is 300 times more potent and also destroys the ozone layer each time it is released into the atmosphere through agricultural practices, sewage treatment and fossil fuel combustion.

Luckily, nature has a larger army than previously thought combating this greenhouse gas--according to a study by Frank Loeffler, University of Tennessee, Knoxville-Oak Ridge National Laboratory Governor's Chair for Microbiology, and his colleagues.

The findings are published in the Nov. 12 edition of the Proceedings of the National Academy of Sciences.

Scientists have long known about naturally occurring microorganisms called denitrifiers, which fight nitrous oxide by transforming it into harmless nitrogen gas. Loeffler and his team have now discovered that this ability also exists in many other groups of microorganisms, all of which consume nitrous oxide and potentially mitigate emissions.

The research team screened available microbial genomes encoding the enzyme systems that catalyze the reduction of the nitrous oxide to harmless nitrogen gas.

They discovered an unexpected broad distribution of this class of enzymes across different groups of microbes with the power to transform nitrous oxide to innocuous nitrogen gas. Within these groups, the enzymes were related yet evolutionarily distinct from those of the known denitrifiers. Microbes with this capability can be found in most, if not all, soils and sediments, indicating that a much larger microbial army contributes to nitrous oxide consumption.

"Before we did this study, there was an inconsistency in nitrous oxide emission predictions based on the known processes contributing to nitrous oxide consumption, suggesting the existence of an unaccounted nitrous oxide sink," said Loeffler. "The new findings potentially reconcile this discrepancy."

According to Loeffler, the discovery of this microbial diversity and its contributions to nitrous oxide consumption will allow the scientific community to advance its understanding of the ecological controls on global nitrous oxide emissions and to refine greenhouse gas cycle models.

"This will allow us to better describe and predict the consequences of human activities on ozone layer destruction and global warming," said Loeffler. "Our results imply that the analysis of the typical denitrifier populations provides an incomplete picture and is insufficient to account for or accurately predict the true nitrous oxide emissions."
-end-
Loeffler collaborated with researchers from the University of Illinois in Urbana-Champaign; the Georgia Institute of Technology; the U.S. Department of Agriculture in Urbana, Ill.; the University of Puerto Rico; and the National Institute of Abiotic Stress Management in Pune, India.

University of Tennessee at Knoxville

Related Greenhouse Gas Articles from Brightsurf:

Make your own greenhouse gas logger
Researchers at Linköping University's Department of Thematic Studies, Environmental Change, have developed a simple logger for greenhouse gas flows.

Old carbon reservoirs unlikely to cause massive greenhouse gas release
As global temperatures rise, permafrost and methane hydrates -- large reservoirs of ancient carbon -- have the potential to break down, releasing enormous quantities of the potent greenhouse gas methane.

Mediterranean rainfall immediately affected by greenhouse gas changes
Mediterranean-type climates face immediate drops in rainfall when greenhouse gases rise, but this could be interrupted quickly if emissions are cut.

Seeking better guidelines for inventorying greenhouse gas emissions
Governments around the world are striving to hit reduction targets using Intergovernmental Panel on Climate Change (IPCC) guidelines to limit global warming.

Nitrous oxide, a greenhouse gas, is on the rise
A new study from an international group of scientists finds we are releasing more of the greenhouse gas nitrous oxide into the atmosphere than previously thought.

Atmospheric pressure impacts greenhouse gas emissions from leaky oil and gas wells
Fluctuations in atmospheric pressure can heavily influence how much natural gas leaks from wells below the ground surface at oil and gas sites, according to new University of British Columbia research.

Natural-gas leaks are important source of greenhouse gas emissions in Los Angeles
Liyin He, a Caltech graduate student, finds that methane in L.A.'s air correlates with the seasonal use of gas for heating homes and businesses

From greenhouse gas to fuel
University of Delaware scientists are part of an international team of researchers that has revealed a new approach to convert carbon dioxide gas into valuable chemicals and fuels.

UBC researchers explore an often ignored source of greenhouse gas
In a new study from UBC's Okanagan campus, researchers have discovered a surprising new source of carbon dioxide (CO2) emissions -- bicarbonates hidden in the lake water used to irrigate local orchards.

Corncob ethanol may help cut China's greenhouse gas emissions
A new Biofuels, Bioproducts and Biorefining study has found that using ethanol from corncobs for energy production may help reduce greenhouse gas emissions in China, if used instead of starch-based ethanol.

Read More: Greenhouse Gas News and Greenhouse Gas Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.