Sandy beach benthic invertebrate macrofauna includes species of several taxonomic groups, with annelids (polychaete worms), mollusks, and crustaceans making up most of its number of species and total biomass. It is usually classified as infauna (organisms living within the sediment) or epifauna (organisms living on the sediment), and strongly influenced by sandy beach environmental characteristics such as sediment type, waves, and tides. Brazilian sandy beach macrofauna has been investigated since the 1970s; however, only in the late 1990s, the scientific production on this topic increased considerably. Although our knowledge of the diversity and ecology of macrobenthic organisms inhabiting Brazilian sandy shores has increased significantly, we are only starting to comprehend their ecological role. In this chapter, we present the main macrobenthic groups found along the Brazilian coast, review important topics of their ecology, and discuss the current knowledge about this important component of Brazilian sandy shores.
