Every Morning, Breanna Roque goes out to the farm to feed the cows. But this isn't your typical farm; it's a laboratory, and Roque is a graduate researcher at the University of California, Davis. She's been spending her time among the cows to see if she can adjust their diets so they burp (打嗝) less. The cows' special diet includes small parts of a red seaweed. It contains a chemical combination, which prevents the production of CH4 during the cows' digestion. Less CH4 means less burping. And less burping could mean slowing down climate change globally.
Although agriculture accounts for a smaller percentage of total greenhouse gas production than sectors like transportation and energy, it produces more CH4, which warms the Earth up to 86 times as much as CO2. When cows eat, they burp food back up, producing CH4 as a byproduct. Researchers across the globe have been pursuing the idea that adding substances to feed might help reduce these CH4-loaded burps. But it wasn't until 2016 that researchers in Australia found that grass feed of 2 percent seaweed could cut CH4 productions by nearly 99 percent. In 2019, Roque's team published the results of a similar study: They cut CH4 production 95 percent by adding to a typical U. S. dairy cow diet with just 5 percent seaweed. But questions remained about the seaweed's effectiveness in actual cow stomachs.
So more researchers headed to the farm. They found that a diet of just 0. 5 percent seaweed led to a 26-percent decrease in CH4. A 1-percent seaweed diet produced 67 percent less CH4. Further research is needed to fully understand why this seaweed in particular works best-and to see if adding seaweed to cows' diets will affect the quality of the products coming from the animals. In the future, they'll run trials to see if seaweed gives cow's milk an unpleasant taste or leaves steaks smelling of seafood.
Researchers still need to ensure the seaweed combination, which is sensitive to heat and light, will be shelf-stable and remain effective in real-world applications. And even if the seaweed succeeds, CH4 from cattle accounts for just 5 percent of greenhouse gas production in the U. S. , so the overall picture won't improve much.
Still, last August, researchers at the University of the Sunshine Coast in Queensland, Australia, announced they would be trying to find ways to farm the seaweed on a large-enough scale to break into the cattle feed market. Roque says she's regularly contacted by annoying businessmen who want her help to mass produce the seaweed for global animal consumption. "People reach out to me all the time, "she says. "Unfortunately, I'm an animal biologist and not a sea biologist. "
