Organisms Beneath the Sand

What’s lurking beneath your beach blanket? Even when a beach looks empty, the sand is filled with life. When you step on a wet beach, there may be a million organisms underfoot. Most are too tiny to see, but they represent more than half of Earth’s major animal groups (phyla). Not even tropical rainforests match this diversity. In addition to many microbes, most of the major animal groups live in sand. Living in beach sand can be tough. Space is tight. Sometimes you’re underwater, sometimes not. Waves continually rearrange your home or threaten to wash you out to sea. Elongated, wormlike shapes make it easier for animals to slither and squeeze through narrow spaces between the sand grains. Most sand-dwellers can’t swim. So when waves threaten to wash them away, they hang on to the sand grains with claws, grippers, and glue-like secretions. Shells, spines, and scales protect tiny animals from the sand grains continually tossed by the waves. (Video has no sound.)