Shallow water benthic ecology: A North American perspective of sedimentaryhabitats

North American benthic research in sedimentary estuarine environments began with an emphasis on descriptions of organism distributions and abundance. These efforts resulted in a crude map of infaunal assemblage types. This ma p is not complete even today but the data allow us to ask questions about p attern. As is typical of such efforts, the majority of the techniques used to evaluate the existence of infaunal patterns are correlative and thus res ult in only weak inferences which do not necessarily expose the causal rela tionships. Such approaches dominated sedimentary benthic ecology until the 1960s and 1970s when investigators began to concentrate to a much larger ex tent on elucidating causal mechanisms. The original stimulus for this chang e has its origins in the work of Sanders and Rhoads and their collaborators who recognized the link between the activities of the infauna and the stru cture of the habitat. Additionally in the 1970s, several investigators with strong ties to rocky intertidal benthic ecology, where manipulative experi ments have been enormously successful, began publishing their work which ac celerated the move to address mechanisms through experimentation. During th e 1980s and 1990s the emphasis on explicit experiments has continued. In th is contribution I explore our current understanding of the processes that l ead to patterns of distribution and abundance in marine sedimentary assembl ages and our ability to ask testable questions concerning mechanism in this habitat.