Introduction and application of a proposed method for quantitative soundscape analysis: The soundscape code

Abstract

A novel methodology for the analysis of soundscapes was developed in an attempt to facilitate quick and accurate soundscape comparisons across time and space. The methodology, proposed here for the first time, consists of a collection of traditional soundscape metrics, statistical measures, and acoustic indices that were selected to quantify several salient properties of marine soundscapes: amplitude, impulsiveness, periodicity, and uniformity. The metrics were calculated over approximately 30 h of semi-continuous passive acoustic data gathered in seven unique acoustic environments. The resultant metric values were analyzed and cross-examined to determine which combination most effectively captured the characteristics of the respective soundscapes. The best measures of amplitude, impulsiveness, periodicity, and uniformity were combined to form the proposed “Soundscape Code,” which allows for rapid multidimensional and direct comparisons of salient soundscape properties across time and space. The soundscape code methodology was then applied at three deep-sea habitats located in the Mid- South Atlantic Outer Continental Shelf (OCS) region that varied in depth, substrate, proximity to shore, and community structure. Soundscape code metrics highlighted nuanced differences in the acoustic environments and allowed for rapid, direct, quantitative comparisons to be made between the sites.