Humanity is endangered by noise pollution, which also poses a serious harm to animals. Kenna Bakker

 According to a sobering study, human noise may even be disturbing fish eggs.

Jan 03, 2023 11.14 GMT

One of the greatest yet least understood health risks of our day is noise pollution. Any metropolitan area in which we live has moderate amounts of noise, which increases the risk of dementia, cardiovascular disease, and cognitive decline. Scientists are now demonstrating that non-human animals are much more susceptible to noise pollution than people and that they, too, suffer from it.

The world's oceans are maybe the place where this is most essential. Sound, which travels quicker and further underwater than light, allows marine creatures to see and perceive their environment. One well-known example is whales, who utilise sound to locate prey, navigate, communicate, and breed. But researchers are now finding that a wide variety of aquatic animals are incredibly sensitive to sound. Marine noise pollution has a dizzying array of adverse impacts, including stunted growth, delayed development, hindered reproduction, and altered migration routes.

Extreme loudness can instantly kill. The base of the marine food chain, zooplankton, may be killed by a single shot from a seismic survey airgun up to a mile distant. It has been discovered that boat engine noise has an impact on fish embryos. According to a sobering study, human noise may even be disturbing fish eggs.

Even watery plants are extremely responsive to sound, which is astounding. Take marine seagrass as an illustration. Seagrass is a carbon sink, much like terrestrial forests, and helps to balance our planet's temperature. Seagrass meadows, which offer food and shelter for marine animals, prevent erosion, facilitate nutrient cycling, stabilise the bottom, and filter pollutants, were formerly common throughout the coasts. Seagrass meadows serve as a pantry, a pharmacy, a hunting ground, and a place of healing on the Pacific island chain. The Posidoniaceae oceanica seagrass colony, which is located off the Mediterranean coast of Ibiza, is the oldest known seagrass colony in the world and is likely closer to 200,000 years old, making it the oldest living creature in the world.

Seagrass meadows the size of the Amazon have disappeared during the past few decades. The construction of seawalls and ports, pollution, boat anchors, dredging, hypersaline water from desalination facilities, and climate change are all possible causes. We may now include noise pollution on this list of dangers, as revealed recently by researchers at the Technical University of Catalonia. The symbiotic fungus that aid in the plants' absorption of nutrients as well as the Mediterranean seagrass were both badly harmed when the researchers subjected a sample to seismic blast-level sound.

Why would plants be responsive to sound when they don't appear to have ears? Marine plants feature organelles called amyloplasts that aid in the perception of sound vibrations, as well as the storage of food, orientation to gravity, and establishment of roots in the seafloor. These little organelles resemble the statocysts seen in shrimp and octopuses, which are able to detect even the tiniest sound waves in water. On the heads and limbs of octopuses, statocysts are arranged in lateral lines. This explains how octopuses can locate prey or predators even without ears, especially at night. They do this by using their arms as hearing devices. Similar to humans, plants use their bodies to hear.

Although their acute hearing is advantageous in the murky ocean depths, aquatic animals are extremely susceptible as a result. Their hearing may be damaged or destroyed by loud underwater noises. These impacts happen at far lower sound levels than those that are known to harm terrestrial animals. Think of a loud siren passing by as an analogy. Imagine if it also causes you to lose your hearing, have digestive problems, and become so lightheaded that you are unable to walk or determine which way is up. In an ocean that is becoming increasingly loud, this is what happens to marine organisms: an onslaught of noise that hinders, damages, and even kills them.

These results highlight how seriously marine noise pollution endangers our seas. Little consideration has been devoted to noise pollution as offshore operations—from seabed mining to oil and gas development and the installation of renewable energy sources—proliferate. Although exposure threshold values have not yet been established, it is certain that new constraints on the authorization and conduct of maritime industrial and shipping activities will ultimately result from this developing research.