9731718 Peterson Soft-bottom benthic habitats represent one of the most ubiquitous environments within the marine ecosystem; however, our knowledge of the processes which determine species abundance and distribution pales in comparison to other types of benthic systems. The majority of past research in benthic systems has focused on the role of predation, disturbance, and competition on adult benthic populations. Recent attention to the potential role of larval supply and the entire recruitment process has greatly expanded our knowledge of the processes which structure benthic communities. Nevertheless, for soft-bottom communities, one large, critical gap exists in our knowledge, the role of secondary movement or redispersal of organisms following larval recruitment. Through a series of field and laboratory experiments designed to address this topic, research will focus on two objectives: to quantify and describe the secondary movement of selected marine benthic macro-invertebrates, particularly juveniles, and to determine the role secondary movement has in structuring soft-bottom communities and mediating interactions of other processes. Research will focus on three common estuarine benthic invertebrates which vary in their dispersal abilities and include two bivalves and one polychate worm. The research will involve direct examination of these organisms in situ and will include a characterization of the hydrodymanic regimes. Research on the interaction of habitat structure, predators and density dependence on secondary dispersion is planned. The results will add knowledge to a poorly understood aspect of the factors which influence community structure and function in soft-bottom benthic environments.