Background: Effects of Underwater Noise Pollution on Marine Animals
Noise pollution in oceans and other water bodies is caused by human activities such as oil exploration, commercial shipping, offshore wind turbines, and seismic surveys. These activities generate excessive and unnatural sounds that disrupt marine ecosystems. Underwater noise pollution particularly affects marine mammals like whales, dolphins, and fish that rely on sound for communication, navigation, and hunting (Iflaw, 2024). The noise interferes with their hearing, making it difficult to communicate, hunt, and coordinate with one another.
Marine species like toothed whales and dolphins, which use echolocation to find prey, are especially vulnerable. High levels of underwater noise can mask echolocation signals, impairing their ability to hunt effectively. The increase in background noise, largely from the approximately 250,000 vessels traveling the world’s oceans, further compounds the problem (Iflaw, 2024). For example, commercial cargo ships can produce up to 190 decibels of noise, which is louder than a plane taking off or a rock concert (Knowlton, 2020). Sound travels faster and farther underwater than in air, amplifying the impact of noise pollution on marine life and their habitats.
Activity: Measuring Sound Levels in Different Water Environments
To understand the impact of noise pollution on marine life, scientists measure underwater sound using hydrophones. Here’s a step-by-step process to measure sound levels in different water environments:
1. Use a hydrophone to detect underwater sounds.
(hydrophone, which uses a piezoelectric material to convert sound into an electrical signal)
To make a hydrophone at home follow the following video https://youtu.be/C3Sm4YkPF9w?si=z5Nb8YUAmonRs_YS
3. Amplify the electrical signals to strengthen them.
4. Connect the amplified signals to a recording device for analysis.
5. Analyze the sound using software to measure characteristics such as pitch, volume, and amplitude.
Future: Disruption of Communication and Navigation in Marine Species
As human activities in oceans increase, so does the intensity of underwater noise pollution, which threatens the survival and health of marine species and ecosystems. Many marine animals rely on sound for communication, mating, navigation, and socialization. Rising noise levels disrupt these crucial activities, especially for species like the North Atlantic right whale, which communicates using low-frequency calls. Increased noise pollution from ships reduces the whales’ ability to hear each other, making it difficult for them to find mates and further threatening their already endangered population.
In addition to communication, noise pollution interferes with echolocation, which many marine animals, from fish to mammals, use for navigation and hunting. Elevated noise levels mask these signals, impairing their ability to locate prey and avoid collisions with vessels. Migratory species are also affected, as noise pollution can disorient them, leading to altered migration routes that prevent them from reaching essential breeding and feeding grounds. This disruption affects population dynamics and ecosystem health, as species may lose access to critical habitats.
Mitigation: Regulating Noise Pollution and Creating Quiet Zones in Oceans
i. Regulating Noise Pollution
One of the most effective ways to control underwater noise is through regulation. Governments and international organizations, such as the International Maritime Organization (IMO), can set standards to limit noise from shipping, construction, and naval activities. For instance, vessels can be equipped with quieter engines and redesigned propellers to reduce cavitation, a major source of underwater noise. Reducing ship speeds in sensitive areas can also minimize noise pollution.
Additionally, noise reduction standards can be applied to underwater construction activities, such as pile driving and dredging, which generate significant noise. Mapping underwater noise hotspots can help policymakers identify areas that require stricter regulations. Collaboration between scientists, industry players, and regulatory agencies is essential to manage and reduce underwater noise pollution effectively (Findlay, 2023).
ii. Creating Quiet Zones in Oceans
Quiet zones are marine protected areas where human activities that produce noise are restricted or prohibited. These zones provide refuges for marine species that rely on sound for communication, navigation, and hunting. Establishing quiet zones in ecologically sensitive areas, such as whale migration corridors or breeding grounds, can reduce the harmful effects of noise pollution. These areas also offer opportunities for scientific research and monitoring to study the recovery of marine species when noise levels are reduced.
References:
Findlay, C. (2023). Noise Management – OCEAN GOVERNANCE MARINE MAMMALS. Marine Mammals Management ToolKit. https://marine-mammals.info/noise-management/
Iflaw. (2024). Ocean Noise Pollution Explained | IFAW. IFAW. https://www.ifaw.org/international/journal/ocean-noise-pollution#:~:text=Underwater%20noise%20pollution%20can%20change
Knowlton, C. (2020, July 1). How does shipping affect ocean sound levels? Discovery of Sound in the Sea. https://dosits.org/science/sounds-in-the-sea/how-does-shipping-affect-ocean-sound-levels/
