Wednesday October 11, 2023
PhysOrg —
Due to the changing climate, the underwater world is getting ever noisier. That is the main conclusion of a study that was published today in the journal PeerJ. “In some places, by the end of this century, the sound of ships, for example, will be five times as loud,” the article’s first author, NIOZ oceanographer Luca Possenti says. “That will interfere with the behavior of many species of fish and marine mammals.”
The study was based on mathematical modeling in collaboration with Utrecht University and TNO, using a moderate or an extreme climate scenario by the UN climate panel IPCC. Both the temperature and acidity of the water affect how easily or difficult sound travels through the ocean. Because of ongoing emissions of greenhouse gases, seawater becomes more acidic, and together with the rise in seawater temperature, the researchers anticipate that underwater sound will travel further in the future in most parts of the oceans.
Because the supply of warmer surface water to the northern Atlantic Ocean will most likely decrease, the researchers foresee a change in temperature layers in this part of the ocean. Possenti says, “As a result of this, a separated ‘sound channel’ in the upper part of the North Atlantic may be formed. This will act as a kind of tunnel, which will carry sounds much further. As a result, the underwater sound level in this part of the oceans will increase by 7 decibels by the end of this century, under a moderate climate scenario.”