Book excerpt: Bivalve filter-feeding mollusks are important components of coastal ecosystems because they remove large quantities of suspended material from the water and excrete abundant amounts of reactive nutrients. These animals are also major prey for numerous predators including birds, fish, mammals, and invertebrates; furthermore, they are significant food resources for humans. While studies on the organismic and population level have dominated bivalve ecology, the recent focus on the ecosystem roles of filter feeding systems has led to larger-scale investigations. With this approach the specific topics of physiology, grazing, predation, nutrient cycling, physical environment, computer simulation modeling, and environmental management are combined into a meaningful whole.