Marine animals are feeling the impact as humans have added to the noise levels in the Earth’s oceans with shipping, fishing and recreation, University of New Hampshire researchers say.
“Underwater soundscapes are not an aspect of the ocean that people naturally relate to because humans are visual creatures, but sound is the dominant sensory mode for life underwater and the masking of biologically significant sounds by elevated sound levels can be detrimental to the health of ocean creatures,” Jennifer Miksis-Olds, research professor and director of UNH’s Center for Acoustics Research and Education, said in a news release.
Researchers gathered, assessed and consolidated evidence from more than 10,000 papers that looked at how anthrophony, or sounds generated by humans, can adversely affect marine animals at multiple levels, including their behavior, physiology, and, in extreme cases, survival.
“What is unique about this work is that is goes beyond just pointing out and describing the societal concern of rising sound levels,” Miksis-Olds said. “It identifies ocean users that have already made a positive, progressive difference in addressing the challenge and proposes action that will guide future ocean users to being sound environmental stewards.”
The paper, published in the journal Science, brought together a global team of researchers to understand how changing ocean soundscapes affect wildlife, from invertebrates to whales, in the oceans.
According to the news release, climate change is also a contributor, leading to the deterioration of marine habitats, such as coral reefs, seagrass meadows and kelp beds. It has further silenced their characteristic sound, which guides the larvae of fish and other animals home.
The paper highlights knowledge gained during the human lockdown under COVID-19 as evidence for the potential rapid recovery of ocean soundscapes when human activity is reduced.
“The deep, dark ocean is conceived as a distant, remote ecosystem, even by marine scientists,” said Carlos M. Duarte, professor of marine science at King Abdullah University of Science and Technology (KAUST) and lead author of the paper.
“However, as I was listening, years ago, to a hydrophone recording acquired off the U.S. West Coast, I was surprised to hear the clear sound of rain falling on the surface as the dominant sound in the deep-sea ocean environment.”
The researchers identify a number of options to allow marine animals to reestablish their use of ocean sound, such as regulating speed and noise in major shipping routes as well as reducing the emissions of chemical pollutants and green-house gases.