Swarms of tiny animals as small as brine shrimp—known to kids the world over as Sea-Monkeys—could have an outsize effect on ocean currents when they swim together in giant herds, according to new research.

Plankton, tiny marine creatures often thought of as mere drifters, actually aren't always so passive. Many move up and down in the ocean in dense layers throughout the day. These collective movements might produce currents large enough to mix seawater, says study co-author John Dabiri, an engineer studying biological physics at Caltech in Pasadena. (See "Sea Animals Change Climate Via Flutters and Flaps?")

If so, this mixing may need to be accounted for in simulations of Earth's future climate, Dabiri says.

Wind-and tide-driven currents move nutrients,