Thursday, August 21, 2008
Scientists in New Zealand from Auckland University claim they have discovered what the 20-30 decibel sounds heard twice a day in the ocean is. Sea Urchins, twice a day, once before sunrise and once before dusk, create this sound by scraping their five teeth along the seafloor scrounging for algae and invertebrates. An urchin's chewing apparatus is called an Aristotle's lantern, due to the ancient Greek philosopher's reference to the mouth's resemblance to a type of five-sided lamp. Other theories coming from this study suggest that the sounds that urchins make, as well as fish grunting and snapping shrimp popping act as beacons to larval fish & crustaceans. Since the ocean is so large with little visual nav points near the surface scientists believe this theory helps to explain how the larva make it to safe waters such as reefs. "They have to find their way back somehow" study co-leader Radford said.