From ocean ambient noise to soundscape ecology

Abstract

Ambient noise in the ocean has been studied for more than 80 years but recently there has been a tendency to use the word “soundscape” for what appears to be the same phenomenon. Ambient noise is usually defined as the background noise from all sources, excluding sounds from individual identifiable sources and is an important limitation on sonar performance and the use of sound by marine animals. The term “soundscape” has been used for decades outside of underwater acoustics with varying definitions depending on the application. Probably the most relevant is “soundscape ecology,” which comes from terrestrial ecology and includes the acoustic interaction between animals and between animals and their environment. A soundscape, therefore, includes all sounds in an environment, not just the background or ambient noise. Sounds from individual identifiable sources may have particular interest to marine animals especially if they are from conspecifics, predators, or prey. This paper discusses the value of applying the broader concepts of soundscapes and soundscape ecology to the underwater environment, the advantages of recognizing the distinction between soundscapes and ambient noise and the importance of soundscape ecology in understanding animal acoustic behavior and the effects of anthropogenic noise.