Ever had builders working next door? Or a neighbour leaf blowing while you’re trying to make a phone call? Unwanted background noise isn’t just stressful, it also has tangible health impacts – for both humans and our marine cousins.
Sound travels faster and farther in water than in air. For marine creatures who rely heavily on sound, crowded ocean soundscapes could be more harmful than previously thought.
Marine animals use sound to navigate, communicate, find food and mates, spot predators, and socialize. But since the Industrial Revolution, humans have made the planet, and the oceans in particular, exponentially noisier.
From shipping and fishing, to mining and sonar, underwater anthropogenic noise is becoming louder and more prevalent. While parts of the ocean’s chorus are being drowned out, others are being permanently muted through hunting and habitat loss.
Given the speed of ocean soundscape changes, researchers want to know more about the impacts of anthropogenic noise on marine life so they can formulate possible mitigation strategies.
The international team, including University of Victoria biologist Francis Juanes, reviewed over 10,000 papers from the past 40 years. They found overwhelming evidence that anthropogenic noise is negatively impacting marine animals.
“We were surprised by how pervasive the effects of anthropogenic noise were geographically and taxonomically affecting all oceans — from the deep-sea to the Arctic, and most animals from invertebrates to marine mammals,” says Juanes.
The data provides ample evidence that noise pollution compromises hearing ability (90.6% of studies report significant impacts), induces physiological changes and stress responses (91.2%), and elicits evasive actions and displaces marine animals (83.9%).
“Anthropogenic noise is an invisible global stressor of marine life that should be considered together with climate change, chemical pollution, overfishing and habitat loss in terms of its global reach and effects,” lead author Carlos M.Duarte, a researcher at King Abdullah University of Science and Technology, told AAAS news.
But there is good news. Unlike other forms of human pollution — like chemical pollutants and greenhouse gases — reducing human-made ocean noise can have almost immediate positive effects.
The study points to evidence from COVID-19, as marine mammals and sharks return to areas quietened by travel restrictions.
Juanes and the research team cite numerous noise mitigation solutions that could keep our oceans quieter long term. From design improvements, to regulating shipping routes and implementing acoustic barriers like bubble curtains, the team hopes that their paper will convince policymakers that underwater noise is an important stressor that needs to be incorporated into future ocean planning.