Baby coral use noise to find their way home
We often think of corals as rocky mineral structures, but they’re really only the homes of the tiny, tentacled organisms. Researchers have found that the flea-sized, free-swimming coral larvae of the phylum Cnidaria, which look like tiny eggs covered in hairs, must quickly find a safe place to establish a colony or else they will die—and they’re able to use sound cues from reefs to orient themselves and find their way home. The research team designed a “choice chamber” for the larvae, set up with underwater speakers. When the speakers were silent, the coral larvae floated aimlessly, but when recordings were played of a coral reef (mainly sounds created by fish and crustaceans), the larvae were attracted the acoustic cues as a known suitable habitat. It appears that close sound stirs up water molecules, which is detected and interpreted by the tiny hair cells called cilia on the larvae’s surface. It’s not yet clear if the larvae can differentiate between reef sounds and other sounds, but if they can’t, human noise pollution such as boats, drills and seismic testing could interfere and become a problem—making our understanding of their life cycle vital in ensuring the coral’s conservation and survival.
Check out a report of the study on PLoS ONE