Otters are at their cutest while cracking open crab shells on their stomachs. But according to one recently released study, that's also when they're combatting water pollution.
A study conducted by researchers at the University of California Santa Cruz found that the otters' recolonization of Elkhorn Slough, one of California's largest estuaries, is indirectly linked to the revival of the ecosystem's once-dwindling seagrass growth.
In ecosystems around the world, seagrass is vital to the health of the coast, but polluting runoff from farms floods the grass with nutrients, sparking algae growth on its leaves and barring the plants from soaking in adequate sunlight.
Elkhorn Slough's seagrass beds, however, were an exception that caught scientists' attention.
The study, published by the Proceedings of the National Academy of Sciences, found that since the otters repopulated the estuary in the 1980s, their insatiable taste for the waters' crabs promoted a regrowth of its seagrass beds.
"With fewer crabs to prey on them, grazing invertebrates like sea slugs become more abundant and larger," UCSC reports. "Sea slugs feed on the algae growing on the seagrass leaves, keeping the leaves clean and healthy."
The researchers hope that the study will demonstrate the importance of maintaining the vitality of each level of the food chain. "It's ... a great reminder that the apex predators that have largely disappeared from so many ecosystems may play vitally important functions," co-author of the study Tim Tinker said.
Sea otters were nearly hunted to extinction for their fur in past generations. According to National Geographic, only 1,000 to 2,000 of them remained in the early 20th century. Today, they've made a massive comeback, and 100,000 to 150,000 sea otters are living and protected by law.