With your eyes closed, clap your hands. You can tell if you are in a small room or a big auditorium by the way the clap sounds. Many people who are visually impaired have learned to use details in what they hear to tell them about their surroundings, because the paths that sounds take from sources (like your hands) to receivers (like your ears) reflect the environments that that they pass through and bounce off of. The environment affects what we hear underwater as well, and we have to account for its influence on our recordings when we make comparisons over seasons and among very different locations.

The goal of the SanctSound project was to understand how sound varies in the ocean by collecting the same information in sanctuaries around the United States. To do this, 30 locations within seven national marine sanctuaries and one marine national monument were selected to listen to the ocean, as continuously as possible, over a period of three years.