By Eleanor Ball
What do you think the “elephant in the room” is when it comes to climate change’s effects on the ocean? Rising sea levels? Melting glaciers? Maybe disappearing species? The authors of a paper published in Science this month argue that this “elephant in the room” is actually noise pollution and its dangerous effects on the marine environment.
Although it may seem like a dark, silent, endlessly vast place to us, oceans are alive with sound to many of their inhabitants. Creatures from fish to marine mammals utilize vocal communication for a multitude of important functions, including courtship, foraging, navigation, territorial defense, rearing of young, and social coordination. For example, dolphins use echolocation to hunt, and Atlantic cod rely on sound to coordinate spawning. Besides intentionally-produced sounds, ambient soundscapes, such as those of coral reefs, are another important part of natural marine noise. Animals such as fish often rely on these soundscapes to find food and safe places to breed. However, as human-produced noise in the ocean increases, animals find it more and more difficult to do all of these things.
Human-produced noise (or anthrophony) in the ocean has been increasing markedly since the Industrial Revolution, muddying the ocean soundscape. Anthrophony has many causes and varieties, such as noise from shipping vessels, which has contributed to an estimated 32-fold increase in low-frequency noise along major shipping routes according to the paper. Other notable sources of anthrophony include seismic surveys, pile-driving, sonar, construction of oil and gas infrastructure, and trawling and dredging. Climate change has also altered the marine soundscape. Changing water temperatures change the way sound travels through water, for example, and the shrinking of formations such as coral reefs affect ambient soundscapes.
Taken together, all this anthrophony confuses the marine soundscape and makes it harder for animals to communicate with each other and pick up sound-based cues from their environment. It can also interfere with their general auditory processing abilities. This can have real, devastating effects. For example, other research has demonstrated how anthrophony can negatively affect the antipredator learning of fish, leading to increased mortality. The impacts on navigation communication have led to other species, such as narwhals, becoming trapped in ice and unable to travel. And when the habitats of some species, like the critically endangered Maui dolphin, are too disrupted by anthrophony for them to continue to live there, they can also rarely effectively migrate because of the specificity of their needs and niche.
While change on this issue will be an uphill battle, the paper’s authors argue it is possible. They suggest a couple of different routes for change: technological innovation and new regulation. There are several promising new technologies that could be utilized to decrease anthrophony, such as acoustic barriers, which can reduce the noise from pile-driving, and alternatives to seismic air guns. Increased regulation of anthrophony could also have positive effects on the ocean. For example, guidelines on shipping routes and speed and ship design can both divert the effects away from ecologically sensitive areas and mitigate the effects where they are still felt. However, ocean noise pollution has not historically--or even recently--been highly prioritized or even acknowledged in much climate change work and activism. Therefore, it’s important to start conversations and raise awareness about this issue so we can start doing the work to mitigate the problem.
Eleanor Ball is a GW Scope staff writer and social sciences editor for the George Washington Undergraduate Review. She is a sophomore majoring in Public Health and double minoring in Sociocultural Anthropology and English. Her most recent research is a project conducted with her county health department during the summer of 2020 to study local racial disparities in the COVID-19 pandemic. At GW, she is also on the boards of the GW Shakespeare Company and the Student Theatre Council.
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