Rick Osman (A.B. Brown University, Ph.D. University of Chicago) is currently a senior scientist at SERC. He is a population and community ecologist working principally with marine benthic invertebrate communities. He has worked extensively with fouling communities in southern New England, southern California, and Chesapeake Bay as well as Florida and Belize. Major themes of his research include: 1) mechanisms controlling the development of communities, 2) physical and biological factors controlling the recruitment process, 3) impacts of invasive species on native communities and factors controlling invasion success, 4) local and regional factors controlling species diversity, and 5) thresholds that control switching between different community states. He also has interests in the processes affecting the establishment and development of infaunal invertebrate communities in marsh habitats and the effects of multiple stresses on benthic populations and communities.