The Estuary as a Filter contains the proceedings of the Estuarine Research Federation's seventh biennial conference at Virginia Beach, Virginia, in late October, 1983. In five invited sessions, scientists and managers considered the physical, geological, chemical-geochemical, and biological processes involved in the ""filtering"" role of estuaries and reflected on management implications of these matters. Most of their presentations and reflections are included in this book in order to demonstrate what is known and what needs to be explored further. The papers in this volume are grouped as they were presented at the conference. Thus, physical oceanographers begin the work by considering turbulence, mixing, and circulation processes in estuaries. Geologists then examine estuarine sedimentation, including the roles of flocculation and bioturbation in accelerating this process. Chemists and geochemists describe the interactions among and effects of inputs of nutrients, metals, and organic matter into estuaries, and the fate of radionuclides in these systems. Biological and biochemical processes involving surface foam, microbes, sea grasses, and wetlands are considered, along with carefully derived nutrient budgets of selected estuarine regions. Finally, some of the problems facing managers of estuarine ecosystems in three areas of the United States are described, along with the success story of the ongoing rehabilitation of the Thames Estuary in England.