Oceans, known for their rich soundscapes created by natural phenomena, are increasingly impacted by human-generated noise, posing serious threats to marine life. The ability of animals to produce and detect sound is vital for communication, feeding, predator avoidance, and navigation in underwater habitats. Human activities such as shipping, infrastructure development, and industrial operations contribute unintentional noise, while deliberate actions like naval sonar and seismic airguns add to the acoustic disturbance.
he consequences of this noise pollution are far-reaching, with evidence suggesting permanent hearing loss, tissue damage, and even death in marine animals exposed to the intense sounds produced by seismic airguns. Seismic surveys have been linked to mass mortalities of squid and zooplankton, highlighting the lethal impact of human-generated noise in the open ocean.
Chronic noise exposure has also been found to affect animal behaviour and physiology. Laboratory studies on sea hares, a marine slug, revealed a 21% reduction in successful embryo development and a 22% higher death rate when exposed to boat noise. The negative effects observed in controlled environments raise concerns about potential threats to entire populations in natural settings.
Marine mammals, relying on sound for communication, foraging, and navigation, are particularly vulnerable to noise pollution. Shipping noise, overlapping with the vocal frequencies of large mammals like blue whales, has led to altered vocalization patterns and increased physiological stress. Changes in vocal behaviour, feeding patterns, and increased stress have been observed in response to shipping noise.
Efforts to mitigate noise pollution include technological developments in ship design, such as reduced propeller cavitation, and adjustments in ship speed. Studies suggest that even a modest reduction in the average speed of commercial ships can significantly lower underwater noise pollution. While technological solutions exist, there is a need for global awareness and more rigorous policies to manage and reduce noise pollution in oceans, ensuring a quieter and healthier future for marine life.
Source: Graeme Shannon, Bangor University