This book includes a comprehensive review of the processes controlling marine ecosystems, communities, and populations, as well as introduces concepts, approaches, and methods in the fast-changing fields of marine ecology and oceanography. This third edition maintains the structure of previous editions, introducing marine environments, dwelling on population, community, and ecosystem levels of organization, and emphasizing relevant biogeochemical and hydrodynamic mechanisms. The content is updated to include major features that new research has revealed in recent decades, but still highlights links to originators of critical ideas in the history of marine sciences. The greatest change in this edition is an expansion of each chapter to capture new awareness, and implications, of the rapid change affecting all aspects marine environments, driven by anthropogenic forces operating through climate and oceanographic mechanisms.