Climate change is changing the way nature sounds.
Professor Ivan Nagelkerken team’s research has been featured in a New York Times article which covers how climate change will silence some species and push others into new habits and habitats, changing when and where they sing, squeak, whistle, bellow or bleat. It will also change the sound animals produce, as well as how such vocalisations travel.
In turn, these changes could make it more difficult for wild creatures to attract mates, avoid predators and stay oriented, as well as force them to expend more energy to make themselves heard. When a habitat is under stress, or being transformed by humans in some manner and is not healthy, it shows in its voice.
The research led by Dr Toullio Rossi is one of five examples that changing climate may modify animals’ acoustic behaviour and remix the planet’s natural soundtracks. This is in the form of snapping shrimp. Shrimp are some of the noisiest creatures in the ocean. By rapidly closing their large claws, the animals make snaps, crackles and pops loud enough to stun prey into submission. Dr Rossi was able to capture these sounds.
But ocean acidification, which occurs as seawater absorbs rising levels of carbon dioxide, could soften their snaps. In studies conducted both in the laboratory and at several underwater vents that naturally spew carbon dioxide, researchers at Australia’s University of Adelaide found that the shrimp snap less often and at lower volumes when the water becomes more acidic.
The lower pH doesn’t seem to damage the shrimp physically; rather, it simply alters their behaviour, possibly by acting directly on their nervous systems. “It’s not that ocean acidification completely takes away their ability to make loud snaps,” said Professor Nagelkerken, a marine biologist. “They can still do that but essentially don’t want to do that any more.”
Ocean acidification is also likely to damage many of the shrimp’s habitats, including coral reefs and kelp forests, and could thus reduce their numbers, resulting in a further drop in sound. Many marine organisms, especially fish larvae, rely on the sound of snapping shrimp to navigate to suitable habitats; if the shrimp go silent, they could have trouble finding their way.