You might not expect it, but cows are a large source of the greenhouse gases that are driving climate change. Now scientists have shown the pollution from cows can be reduced by adding a little seaweed to their food.
A cow has one stomach, but it has four separate sections, one of which has a special chemical that helps break down the grass into something the cow's body can use. But the process of breaking down the grass produces much methane(甲烷), the world's second worst greenhouse gas.
Recently, the researchers from the University of California, Davis studied 21 cows on a farm for about five months. They taught the cows to get their food from inside a special hood(罩), which allowed the scientists to know the amount of the methane the cows were giving off. They used a small amount of seaweed, which they mixed with the cows' food.
The results were surprisingly good. In some cases, the cows produced 82% less methane- the improvement depended on the kind of food the cows were given. And even the worst- polluting cows produced 33% less methane.
Over the five months, the scientists didn't see any signs that the cows' stomachs were starting to produce more methane again. Besides, the cows that were fed seaweed gained just as much weight as the other cows, but they didn't need as much food.
But there are still some big problems with the idea of feeding cows seaweed. For one thing， there's not enough seaweed to feed all of the cows in the world. So farmers would have to figure out a way to grow lots of seaweed. A bigger problem is that for most of their lives, cows live in fields, where they eat the grass. That means there's no chance to feed them seaweed every day.
Still, it's very good news that something as simple as feeding cows seaweed can help reduce some of the pollution causing the climate crisis.
