Underwater noise pollution is causing turtles to experience hearing loss that can last from minutes to days, reveals a study of the Woods Hole Oceanographic Institution.
Activities such as shipping and construction generate a lot of noise in both freshwater and saltwater environments. Previous studies have focused on the effects of noise on a variety of animals, from squid to fish to whales. But less work has been done on reptiles, such as turtles, said Andria Salas, a researcher presenting the findings in a statement from the American Geophysical Union (AGU).
“Our preliminary findings are the first to support that these animals are underwater after exposure to intense noise. Salas said. “We have assumed that turtles experience hearing loss when exposed to loud enough sounds as seen in other animals, but no turtle-specific data has been collected.”
Salas and his colleagues were surprised by the relatively low level of noise that affects the turtles’ hearing, which The new findings could have implications for the survival of some threatened turtle species.
“If this occurs in the wild, turtles would be less able to detect sounds in their environment on these timescales, including sounds used to communicate or warn them of approaching predators.” said. “More than half of the land and sea turtle species are threatened, and noise pollution is an additional stressor to consider as we work to protect these animals.”
The most important thing -says the institution- is that in this case the results of the study can help predict the largest and most harmful noise impacts, “with permanent hearing loss or hearing damage”.
Salas and his colleagues focused their experiments on two species of non-endangered freshwater turtles. They used a minimally invasive electrode, inserted just under the skin above a turtle’s ear, to detect very small electrical voltages created by the turtles’ auditory system when they hear sounds. Before exposing the turtles to loud (high-amplitude) white noise, the researchers first determined what and what tones (frequencies) they heard best.
After exposing the turtles to noise and then removing them from the noise, the researchers continued to measure the turtles’ hearing for about an hour to see how short-term their underwater hearing recovered, and then checked two days later to see if the recovery was complete.
While the tortoises always recovered their hearing, the hearing loss, however, sometimes had not recovered by the end of the test hour, indicating that they needed more time to fully recover from the noise exposure. One tortoise’s hearing was affected for several days.
With information from Europe Press