These researchers hope their new finding could lead to tips for cutting methane emissions from farm animals.
Some chemicals in the atmosphere, known as greenhouse gases, trap incoming heat from the sun. This leads to warming at the Earth’s surface. Methane is one of the most potent of these greenhouse gases. Its impact on global warming is more than 20 times greater than that of carbon dioxide, the best-known greenhouse gas.
Cutting the methane released by livestock could slow global warming. Scott Godwin works for the Queensland Department of Agriculture, Fisheries and Forestry in Brisbane, Australia. He and his coworkers thought studying the germs responsible for kangaroos’ flatulence (ahem, farts) might offer clues on how to do this.
To sniff out the kangaroo's secret, the microbiologists collected microbes from the digestive tracts of three wild eastern gray kangaroos. They also collected microbes from cows.
These microbes had been dining on the animals’ last grassy meals. The scientists placed the microbes in glass bottles and let them continue to break down the grasses. The bugs do it through a process known as fermentation.
In many animals, this fermentation creates two gases, carbon dioxide and hydrogen. But in animals like cows and goats, other microbes called methanogens gobble up those substances and turn them into methane.
In the kangaroo experiment, the scientists did find some of those methane-making microbes. But some other germs were active too, they reported March 13 in ISME Journal. One key hint: The gas produced by 'roo microbes smelled unusual — like manure with a bit of vinegar and parmesan cheese.
Among the kangaroos’ microbes were acetogens. These microbes take in carbon dioxide and hydrogen — but make no methane. They instead produce a substance called acetate.
Acetogens compete with methanogens in the digestive tracts of animals. Methanogens usually win, Peter Janssen told Science News. He’s a microbiologist at the New Zealand Agricultural Greenhouse Gas Research Centre in Palmerston North. He did not take part in the new study.
In kangaroos, though, the acetogens often win the battle, the researchers report. The result is fairly low levels of methane.
The new research does not fully explain the greener gas of kangaroos, Janssen says. In fact, it raises questions about why methanogens don't always win out in kangaroos.
“It’s an important first study,” he says, and the research offers a clue about where to look for answers.
Acetogens also live in the digestive tract of cows, Godwin told Science News. If scientists could find a way to give their acetogens an edge over their methanogens, cows too might produce low-methane farts and burps." (https://student.societyforscience.org/article/kangaroos-have-green-farts)
