Sound of the Sea
By Ailbhe Doyle
Our sea is a place we go when we need to clear our heads, reset, and listen to the ebb and flow of the tide. We are lucky because our sea is a place where our senses get a chance to relax from a day or a week of sensory overload in work, college, and just life in general. We then leave the sea, but can return as we wish.
The marine life, however, are not as lucky, as the sea is becoming a deafening world from which they cannot escape. Marine animals have developed over millions of years to use aural senses as their number one method of communication and navigation. Sound travels nearly twice as fast as light in the ocean and, therefore, auditory senses, as opposed to visual, have developed to be highly efficient.
Cetaceans (dolphins, whales, porpoises) for example, all use clicks, whistles, and calls to survive in the dark and low-visibility environments in the ocean. Looking at bottle-nosed dolphins, they have developed so well that their bottom jaw includes a casting of fatty substance that absorbs sound from a strikingly large frequency range, while emitting the sound from the melon (a mass of fatty tissue) at the front of their skull. Whales, a species that communicate on a much lower frequency, can emit calls that travel for distances as long as 16,000km!
These fascinating species rely solely on sound for survival and the increasing anthropogenic noise within the water is driving them into psychosis, causing them to haemorrhage and is also the main cause of marine life beaching on our shores. There is four times more traffic on our oceans than only twenty years ago, and this along with increased building of, and searching for, offshore energy (both renewable and fossil) has taken any peace that was once in the sea and replaced it with an inundation of noise.
We must realise just how lucky we are that we cannot hear our own destruction of the peace beneath the water.
Due to the sensitivity of marine life to sound, it is creating an inhabitable environment from which they cannot getaway. They end up looking for shallower waters, to which they cannot physically adjust and die, or stranding themselves on the coast. It also means they are losing their only system of communication, navigation, and foraging due to their own sounds being drowned out by those manmade eruptions of noise. This is pushing life in the water further into species decline at an alarming rate.
However, there is hope for our seas returning to a quieter place again. Germany, for example, has put a maximum hectohertz (the measure of sound in water) on any new ships being built. In fact, it only takes a simple adjustment of the engine to make a ship 90% quieter! We must also stop building and detonating within our waters and keep up the research on acoustic behaviours in our marine life. Discovering the areas we need to keep silent for their vital mating and breeding seasons is of utmost importance. For now though, being aware of this huge, underreported issue is key. We must realise just how lucky we are that we cannot hear our own destruction of the peace beneath the water.
