There are around 1,250 different species of sea cucumber scattered across the world’s oceans, and they occupy many different niches. For instance, some bury themselves completely in sand, like worms, while others snag food as it floats by in the water column, like corals.
Others, like the deposit-feeding sea cucumber, Thelenota anax, walk across the sea floor mopping up sediment and stuffing it into their mouths with an array of tentacles.
“One at a time, over and over,” says Richard Strathmann, a marine biologist and professor emeritus at the University of Washington. “It has always looked to me like a peaceful sort of life.”
Because these animals eat the organic materials found wedged in between all that sand, what comes out of a sea cucumber is actually ‘cleaner’ than what went in. And this simple process of sifting through the sediment—which scientists call bioturbation—can have quite an impact on the makeup of the ecosystems they live in.
Read the full story on National Geographic.