Weird method

Nitrous oxide eaters to reduce greenhouse gases

(Bild: thinkstockphotos.de)

Under certain conditions, soil bacteria in nitrogen-fertilized agricultural soils produce nitrous oxide, which is responsible for a significant proportion of greenhouse gas emissions from agriculture. A bacterium has now been discovered that simply "eats" the nitrous oxide produced in the soil.

The widespread use of nitrogenous fertilizers leads to emissions of the greenhouse gas nitrous oxide (N2O) - also known as "laughing gas" - from agricultural soils. According to the Norwegian University of Life Sciences (NMBU), these emissions currently account for around a third of the total greenhouse gas emissions caused by agriculture. Until now, it was assumed that they were unavoidable.

Researchers from Norway and Austria report in the journal "Nature" on a bacterium that literally "eats" nitrous oxide produced in the soil. If used widely, it could prevent it from escaping into the atmosphere.

(Bild: EXPA Pictures)

Nitrousoxide is 300 times more potent than CO2
Under certain conditions, nitrous oxide is produced by microorganisms in the soil: If these do not have access to oxygen, they are forced to find other ways to obtain energy, for example by respiring nitrate instead of oxygen. In a process called "denitrification", the nitrate is converted into nitrous oxide, among other things. "This greenhouse gas has around 300 times more impact than CO2, and agriculture is responsible for around three quarters of N2O emissions in Europe," explained Wilfried Winiwarter, one of the co-authors of the study from the International Institute for Applied Systems Analysis (IIASA) in Laxenburg near Vienna, in a press release.

After a long search, the scientists have now identified a special type of bacteria that can reduce nitrous oxide to harmless nitrogen gas (N2), but cannot produce nitrous oxide itself. This bacterium "simply lacks the gene to produce nitrous oxide, it can only eat it," says Elisabeth Hiis from the NMBU.

The research team is now working on finding more nitrous oxide "eating" bacteria. This method could make it possible to reduce agricultural nitrous oxide emissions in Europe by a third.