Scallops cough to expel feces and water from their central cavities. The friction between the mollusk’s two valves makes a sharp crack, followed by a drawn-out puffing sound as the valves close. Biologists think that these coughs could serve as an early warning system for worsening water quality.
The scientists published their findings in the Journal of Experimental Marine Biology and Ecology. Because the sonically striking coughs are distinct from the choruses of other marine organisms like shrimp and sea urchins, the researchers discovered that they could record the scallops’ coughs from up to 10 meters away by using hydrophones, which are submersible acoustic sensors.
Previous research has indicated that scallops feed less often and grow slower in the presence of toxic algae and decreased levels of oxygen concentration. Scientists could monitor the changes in water quality by analyzing fine-scale growth patterns in the tiny ridges of scallop shells, but they feel it will be less labor-intensive to set up a network of hydrophones to track the coughing behaviors of the animals instead.
This method could replace the current, more disruptive method of tracking scallops. Usually, scientists attach motion sensors directly to their shells. The researchers plan on exploring other kinds of scallop movement, such as digging, swimming, jumping and spinning. These could reveal more sonic qualities useful for diagnosing the health of the oceans.
Reference: “Hydrophone detects cracking sounds: Non-intrusive monitoring of bivalve movement” by Lucia Di Iorio, Cédric Gervaise, Virginie Jaud, Anthony A. Robson and Laurent Chauvau, 30 November 2012, Journal of Experimental Marine Biology and Ecology.