Introduction to the special issue on assessing sediment heterogeneity on continental shelves and slopesa).

Over the past decade, an interdisciplinary team of scientists conducted a series of at-sea measurements designed to further our understanding of acoustics in complex ocean environments. Most of these efforts focused on bottom-interacting acoustics in areas characterized by fine-grained sediments. Geographically, the primary experimental sites and data analysis took place in an area of the Western Atlantic Ocean approximately 60 miles south of Martha's Vineyard, MA, known as the New England Mudpatch, and extending south to include the shelf break and upper slope characterized by larger-grained sediments. This introductory paper provides a summary of the various experimental techniques and analysis approaches detailed in the collection of 23 papers that make up this special issue focused on Assessing Sediment Heterogeneity on Continental Shelves and Slopes.