Marine sound propagation refers to how sound travels through water. In the ocean, sound waves can move faster than in air due to water's higher density. Factors like temperature, salinity, and pressure affect how sound travels, creating different paths and distances for sound waves. Underwater, sound can reflect off surfaces like the ocean floor or bounce off layers of water with varying temperatures, known as thermoclines. This can create complex patterns of sound movement, which is important for marine life communication and navigation, as well as for human activities like sonar and underwater exploration.