Living in an environment of noise pollution of the World Ocean, dolphins begin to communicate in simpler and shorter "phrases".
Annoying sounds of anthropogenic origin - for the most part from various means of transport - are the source of a special form of environmental pollution, noise. It has a subtle but negative impact on human health and nature. The noise of ships, submarine sonars, and wind turbines has a particular impact on the life of marine animals, which use sounds for communication and orientation. It is assumed that it is he who can lead to the throwing of whales and dolphins ashore, "knocking down" the operation of their echolocation systems.
Helen Bailey and her colleagues at the University of Maryland's Chesapeake Biological Laboratory have discovered another unexpected result of the effects of noise pollution on ocean inhabitants. In an article published in Biology Letters, they note that the phrases that sociable dolphins exchange get shorter and easier the closer they are to places of high sound pollution. As if we ourselves had to talk in a very noisy room.
Deploying a bottom network of recording devices, scientists investigated the noise environment in the northwest Atlantic Ocean, off the coast of Maryland and the Chesapeake Bay. After analyzing the recordings, they found that the level of background noise correlated with the characteristic changes in the acoustic signals exchanged between bottlenose dolphins. Their chirping "phrases" are shifted to higher frequencies, shorter and simpler. Simplifying these whistles, says Leila Fouda, one of the authors of the paper, can reduce the amount of information contained in the signals and complicate dolphin communication.
Indeed, dolphins are able to compete with humans in terms of communication. They talk, maintaining social bonds in the pack and contact when moving, coordinating during the hunt and simply greeting acquaintances when they meet. Normally, their speech is complexly structured, contains a set of whistles and clicks of different duration, pitch and timbre. And all these characteristics fall in the vicinity of active shipping. According to scientists, in some areas, they recorded background noise, reaching 130 decibels - like the side of a busy highway. “We need to work to create quieter ships,” sums up Professor Bailey.