Under water, a coral reef seems like quite a tranquil place. But up close, the tiny animals that make up the reef are wildly waving their tiny hairlike projections, creating quite a rip tide that sweeps in food and nutrients, BBC reports. Researchers discovered that corals stir up the water around them by studying them through a microscope with high-speed video cameras. Until now, researchers thought the corals just pushed water along their surfaces to remove mud and sand that might cut down on light. But it turns out that in at least six coral species, the cilia do much more.