Ocean noises are known to be the sound that is made by human activities. These sounds interfere with and obscure the natural sounds made by marine animals. Ocean noise is usually caused by construction, shipping, seismic, and sonar surveys. According to scientists, these loud sounds drown the natural and healthy soundscape of the ocean bodies.
Most marine animals are dependent upon the ability to hear which is crucial to their survival. This is mainly due to the reason that sound is acutely efficient because it is a convenient means of communication for underwater organisms. It is also the primary way in which numerous marine organisms assemble and understand the information regarding their environment.
Marine animals make use of sound abilities in order to find food, hunt prey, avoid predators, locate mates, navigate and locate habitat. In addition, they also communicate and hear each other through sounds. However, over the past century, ocean noise from human activities including shipping, boating, recreational, and industrial exploration has greatly increased along the offshore, coasts, and deeper water environment.
Ocean noise has the ability to travel long distances underwater. The rising level of noise has negatively affected aquatic organisms and ecosystems. Ocean noise has also reduced the ability of marine animals to listen to environmental cues which are vital to their survival.
Causes Of Ocean Noise
Seismic airguns have been mainly used for gas and oil exploration below the seabed as well as for various geophysical surveys of the seafloor. In this process, the air is pushed into the water through high pressure that sends explosive and intense sound pulses to the seabed. Almost 40 airguns in tight sequence are fired for weeks in the same location. This creates ocean noise that penetrates over 100 km across the ocean floor.
Military sonar often conducts routine activities and exercises to patrol and monitor submarines. These sonar systems emit over 100 seconds of sound pulses for hours. Moreover, these pulses emit a huge amount of energy within a narrow range. 90% of the traded goods all over the world get transported through ships that generate persistent increasing acoustic ‘fog’. Ships normally produce low-frequency ocean noise ranging from 10Hz to 1 kHz.
Explosives also get detonated in the water bodies during military and demolition purposes or equipment testing trials. In addition, construction work also creates intensive ocean noise across a large frequency range.
Impacts Of Marine Life
Over the last couple of decades, humans have increasingly altered the ocean soundscape. Ocean noise pollution has significantly increased and has stranded dolphins and whales in large numbers. Strandings are the most common phenomenon that occurs following naval sonar activities.
Extreme sound activities have vascular damage on the lungs, brain, and several other organs of aquatic organisms. Additionally, animals might quickly panic that further leads to nitrogen bubbles forming in their blood and causing death. Animals that finally die sink to the seabed or end up on the coastal beaches.
Just like humans, loud ocean noise results in hearing damage which is a serious issue since they greatly rely on hearing to communicate, sense danger, and other underwater activities. Other physical repercussions such as disruption of schooling structure or impaired growth of fishes and shrimps.
Several marine species have already started fleeing or migrating from their normal valuable habitats. The main reason being the direct impact of the rise in ocean noise. Grave consequences occur among marine populations which become weakened due to the disruptions in their normal patterns.
Reducing human activities around coastal regions must be the first step towards reducing ocean noise pollution. The water bodies are already damaged due to the plastic wastes and the sound is an added pollution.