A different kind of water pollution
Noise Pollution of Liquid Environments
Water is an insonifying environment meaning that sound travels both faster and further in this liquid environment. Although focused on the ocean, The Guardian’s Oceans of Noise podcasts teach us that water can be polluted by noise. In one of Chris Watson’s recordings taken on a hydrophone (Episode 1) the clear hammering of an Arctic icebreaker is heard 12 km away from the recording spot. This quickly leads listeners to the realisation that the rich marine acoustic environment is constantly being polluted by anthropogenic sources such as shipping, hydrocarbon exploration, and seabed mining activities.
Professor Chris Clark from Cornell University goes on to explain that marine mammals’ communication method (echolocation) is severely compromised by this and is having an effect on their navigation to both feeding and breeding grounds; and it’s not only larger animals such as whales but noise pollution is also influencing krill populations (zooplankton) and fish such as Norwegian Cod that humans depend heavily on for food at many levels of the food chain.
Scolt Head Island National Nature Reserve, Norfolk
Nicolas Entrup of Oceancare puts the onus on governments to act against lack of concrete actions and non-compliance for polluting waters with noise. The EU Water Framework Directive’s principle of bio-assessment compares observed and expected community numbers and aims to define Emerging Stressors on the aquatic environment but does not factor in metrics such as noise or climate change. Hering recommends “keeping assessment systems flexible and adding metrics specific for emerging stressors” as a legislative control.
Marine life being able to use sound effectively for survival may be disabled to an even greater extent as our reach in the oceans stretches further and further and human-made underwater noise starts to affect the social networks of marine mammals and become a contributing factor towards the survival and reproductive success of some species.