This text, with individual chapters written by researchers in marine ecology, explains the structure and organization of the groups of organisms that live on the sea floor. The first section covers general processes and how physical and biological forces combined with historical and genetic constraints work to structure marine communities. The second section examines specific benthic community types, such as rocky shores or soft substrate habitats. The book concludes with three chapters exploring conservation and management issues and emphasizing how these communities are impacted by human activity.