Ocean Noise Pollution The noise that affects sea creatures comes from a number of human activities. It is caused mainly by industrial underwater explosions, ocean drilling, and ship engines. Such noises are added to natural sounds. These sounds include the breaking of ice fields, underwater earthquakes, and sounds made by animals themselves. Some scientists have proposed setting a noise limit of one. hundred-twenty decibels in oceans. They have observed that noises at that level can frighten and confuse whales . Many researchers， whose work depends on ocean sounds object to a limit of one-hundred-twenty decibels. They say such a limit is a greater danger than they believed. They want to prevent noises from harming creatures in the ocean. A The sound of a car. C Man-made noise pollution.