Climate change is warming up oceans all over the globe. While the warmer water temperatures affect a variety of ecosystems and species, the impact of a changing ocean soundscape has not been extensively studied.
While whales and dolphins heavily rely on sound to communicate and socialise, a new study now suggests that warmer ocean temperatures might speed up underwater sounds, thus directly affecting marine fauna.
The team of researchers behind the study analysed future climate change consequences on underwater sound propagation by basing their model on a high-emissions scenario that is predicted for 2100 if greenhouse gas emissions are not further reduced. They found that ocean warming could accelerate the speed of sound underwater across the globe.
Due to physical principles, sound travels faster in warmer water, while sounds also last longer before they fade away. Two hotspots for this development were identified in the northwestern Atlantic and the Greenland Sea where the average speed of sound could increase by more than 1.5% over the current speed. The researchers say that the phenomenon could contribute to “the impending risk of biodiversity loss at global scale” in these hotspots with “major variations” expected in most seas by the end of century.
As part of the study, the research team analysed the sound patterns of the critically endangered North Atlantic right whale of which only around 350 individuals are believed to exist today. In regards to the whale’s echolocation, Alice Affatati, a bioacoustics and underwater noise researcher at Memorial University of Newfoundland and Labrador, said: “If that gets distorted, it might have an impact on their feeding habits.”
The team found that the call of a right whale directed to another would travel further and faster in a warmer ocean environment. In turn, the whales could get thrown off by the sound shifts and could migrate away from their natural habitats as a consequence. This could also have a direct effect on the food web.
However, some animals might be able to adapt to these new soundscapes by changing their vocal abilities. After all, previous studies have shown that some cetaceans are indeed able to modify their frequencies in noisy environments.
The study is yet another reminder of how human activity such as shipping noise might further affect species and ecosystems in a warming environment.
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Photography courtesy of Unsplash.