Oceans, Part 3

“In every curving beach, in every grain of sand, there is a story of the Earth.”       [Rachel Carson]

Whenever I get the chance to go snorkeling, I’m always happy to see parrotfish. I’m not sure why I like them so much. Maybe it’s because they always look like they are smiling. Or that you can see their perfect teeth (which form a parrot-like beak). Or how colorful some of them are.

Recently I learned an especially cool fact about parrotfish – they poop sand. Like many people I’d always thought that sand was the byproduct of hundreds of years of erosion and the weathering of rocks. That is still true. But there’s more to the story. On some beaches around the world, the sand is the byproduct of parrotfish. Here’s how it works. Parrotfish scrape off coral with their beaks. The soft tissues of polyps, bacteria, and algae are absorbed. The hard calcium carbonate skeleton of the coral, however, is processed and pooped out as sand! A large parrotfish can produce hundreds of pounds of sand a year. I will never look at sand or parrotfish the same.