As oceans warm, snapping shrimp sound a warning

In a warming ocean, brittle shrimp could be the acoustic canary in the coal mine.

Research published today by Woods Hole Oceanographic Establishment (WHOI) scientists in Frontiers in Maritime Science confirmed their previous observations that rising temperatures increase the sound of snapping shrimp, a tiny crustacean found in temperate and tropical coastal marine environments worldwide.

In the first study of this variety, WHOI marine ecologists Ashlee Lillis and T. Aran Mooney established a clear relationship between rising temperatures and the frequency and volume of sound emitted by two species of snapping shrimp, with implications for underwater navigation and human interaction. and animals. The continuous clicks emitted by the snapping shrimp – which evoke the sound of sizzling bacon – are so loud and cover such a wide acoustic range that they interfere with the vessel’s sonar and fish finders. Research shows that whales and dolphins can rely on the sound of slapping shrimp to orient themselves along the coast, and various soundscapes help attract fish, crustaceans and coral larvae to fishing sites. sedimentation.

“These shrimp are the most ubiquitous sound producers in the ocean, and we now have evidence that temperature has a huge impact on their behavior and the global soundscape,” said Lillis, OMSI Visiting Scholar and Senior Scientist at Audio Ocean Science. “It’s about everything from migrating whales to larvae trying to use the soundscape, or humans using the sea for extractive or military purposes.”

Lillis analyzed snapping shrimp recordings from an oyster reef off the coast of North Carolina and found an increase of 1-2 decibels, as well as an increase of 15 to 60 % of the breakout frequency, for each degree Celsius increase in temperature. When tested in a controlled lab, Lillis found that the frequency of popping doubled with water temperatures between 68 F (20 C) and 86 F (20 C), with some differences by season or social group of shrimp.

The experiments simulated the effects of a short-term heat wave, so it is not yet clear whether the shrimp might eventually adapt, or how increased breakage might affect their physiology or the ecosystem over time. While temperature has long been known to impact the behavior of crustaceans, the effects of warming water on the world-wide marine soundscape are a crucial – and often overlooked – offshoot of climate change, says Mooney.

“Climate change has a fundamental affect on the marine soundscape,” Mooney said. “Warming waters can influence how animals are physically able to communicate and use sound to reproduce and attract mates. We don’t yet know what happens to the ecosystem when background levels are higher, but there are far-reaching implications.”

Funding for this research was provided by the NSF Organic Oceanography Grant # 1536782 and the Interdisciplinary Award and Programs of postdoctoral researchers from the Woods Gap Oceanographic Institution.

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