Multidimensional comparison of ocean soundscape properties across depth and substrate type

Abstract

The local soundscape is determined by its physical environment, human activity, and presence of soniferous marine life and, therefore, provides insight on ecosystem processes, habitat quality, and biodiversity. Shallow coral habitats in tropical environments are hotspots of biodiversity and marine life. Deep-sea coral environments along the southeastern U.S. provide important habitat for a variety of marine animals but are generally poorly understood. An innovative Soundscape Code methodology for quantitatively characterizing soundscapes was applied to passive recordings from four locations along the US Outer Continental Shelf (OCS) and one from the Great Barrier Reef to assess how differences in habitat, depth, and substrate manifest acoustically. Comparisons were made between (1) deep, cold-water and shallow, warm-water coral reefs and (2) deep-sea coral and sandy bottom habitats. The shallow, tropical reef soundscape differed from the deep-sea soundscapes in amplitude and impulsiveness. Differences in soundscape properties among the deep-sea soundscapes suggest deep-sea coral sites produce different soundscapes than the deep sites without live hardbottom. Biologic and anthropogenic signals influenced the deep-sea soundscapes and represent fundamental differences in habitat. This initial assessment of deep-sea soundscapes along the US OCS provides baseline acoustic properties in a region likely to experience changes in climate and human use.