Research has found that coral larvae detect and move towards sound when looking for reefs, but that manmade noises may also endanger it.
Baby corals find their way to reefs by detecting the sound of snapping shrimps and grunting fish, scientists revealed today. It had long been assumed that coral larvae drift aimlessly after being released by their parent colonies and almost by chance land back on reefs. But scientists now believe that though they are anatomically very simple, the larvae can pick up the sound of a reef and head towards it.
One of the experts involved in the study, Steve Simpson, senior researcher in the University of Bristol's School of Biological Sciences, said: "Until recently we assumed that these larvae drift aimlessly, but this study shows they are able to detect sound and move towards it. This could help them find bustling reef habitats but may also draw them towards human sources of noise such as turbines and drilling operations."
Simpson said a reef was a noisy place but usually when humans dive they hear little but their own breathing. But actually a reef is full of "clicks from snapping shrimps that combine to produce a crackling noise and grunts and chirps produced by fish as they communicate."
How the creatures, which look like tiny eggs covered in hairs, detect sound is unknown. Simpson said: "At close range sound stirs up water molecules, and this could waggle tiny hair cells on the surface of the larvae, providing vital directional information for baby corals."
The discovery is worrying as it is feared the larvae might also be drawn to dangerous man-made sounds in increasingly noisy oceans or struggle to find reefs because human noise masks their sound. "Anthropogenic noise has increased dramatically in recent years, with small boats, shipping, drilling, pile driving and seismic testing now sometimes drowning out the natural sounds of fish and snapping shrimps," he said.
via University of Bristol