A New York Times article describes the cacophony that assails our oceans. Let’s be clear: before man’s intervention, the oceans were by no means silent. Clicking and snapping noises from shrimp and other crustaceans, the songs of whales, and the vocalisations of various other creatures have always been a part of life under the surface. However: the advent of modern warfare, requiring weapons testing and the use of sonar, and the constant propellor and engine noise from the commercial and cruise ships that ply the world’s oceans, has elevated the underwater noise level to an alarming volume.
The noise under the sea is specially dangerous to cetaceans, who occasionally engage in mass strandings when – it is believed – their navigation abilities are confused by loud sonar blasts. Many whales also have very sensitive hearing, not adapted to the loud blasts that are now commonplace in their habitat. Every year thousands of marine mammals suffer hearing damage and loss as a result of man’s activities in the sea.
A first step in reducing undersea noise is a visualisation of the problem. The USA’s National Oceanic and Atmospheric Administration (NOAA) is engaged in a project to map the noise level in the ocean, indicating the number of decibels using a colour heatmap. Once it is understood where the noisy places are and what is causing the racket, steps can be taken to reduce the noise. These include better propellor design on ships, and mounting noisy machinery on mechanisms to isolate its vibrations from the rest of the vessel.
Read the full article here. There’s an interactive companion map showing estimated noise levels that’s also worth checking out.
