Nitrous oxide might make root canals bearable, but the world-warming gas is no laughing matter for the planet.
It is commonly called laughing gas for its ability to create a state of euphoria when inhaled. Experts at the Norwegian University of Life Sciences also know it as the "forgotten greenhouse gas," because it warms the planet around 300 times more effectively than carbon dioxide, according to a lab summary — an estimate supported by the U.S. National Oceanic and Atmospheric Administration, for a 100-year time span.
Per the lab report, it represents 4.8% of Norway's heat-trapping pollution and also damages the ozone layer. That's why the researchers are growing bacteria that can consume the fume at its leading source: fertilizer.
Our growing population and food demand is a large reason why nitrous oxide has spiked in abundance during the last 200 years. Although it is not as abundant in the atmosphere as carbon dioxide or methane, nitrous oxide is potent and can linger.
"We have a major challenge because we need to maintain global food production while reducing N2O emissions," doctoral student Elisabeth Gautefall Hiis, who is working on the project, said.
While bacteria are plentiful in soil, they often create nitrous oxide when they consume nitrogen, a component of fertilizer that on its own can cause big problems in our waterways when it is washed off fields and into rivers and streams. The runoff can cause large fish kills and other disasters, the U.S. Environmental Protection Agency notes.
Hiis and other researchers had to scour through soil samples that contain billions of bacteria per teaspoon to find the kind that are hungry for laughing gas (and converting it into a harmless nitrogen gas), according to the lab summary. They eventually found one that fascinatingly "eats" it, reducing nitrogren pollution from soil by between 40% and 95%.
"Some of the bacteria we initially looked at can both eat and produce nitrous oxide. That made it complicated. One bacterium, for example, would eat nitrous oxide in the laboratory, but once it was in the soil, it had little effect," Hiis said.
A type of cloacibacterium, dubbed the "one-armed bandit" by the team, was found to be the nearly perfect fit for the task.
"It simply does not have the gene to produce nitrous oxide, it can only eat it," she said in the summary.
Experts at labs elsewhere are working on technology to help farmers better manage fertilizer use. The University of Texas at Austin is developing a hydrogel that can catch excess nitrate from fields before it pollutes the surrounding environment. There are around 895 million acres of farmland in the U.S. alone, per the Department of Agriculture.
Growing your own food at home in gardens or raised beds is an excellent way to learn about sustainable agriculture while reducing waste and pollution. A $70 investment can produce $600 worth of food each season. Composting food scraps prevents the would-be garbage from filling gassy landfills. The process also creates great soil for future gardens, limiting fertilizer use.
In Norway, the experts are using a robot that rolls through a test field, checking laughing gas pollution. The nitrous oxide-eating bacteria are grown in organic waste before being introduced to the soil. This method provides the tremendous amounts of bacteria needed to be effective.
Now, the team is working to commercialize the science.
"It gives us hope for both productive and low-emission food production in the future," Professor Lars Bakken said in the lab report.
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