Biodiversity loss in terrestrial environments associated with human activities has been appreciated as a major issue for some years now. What is less well documented is the effect of such activities, including climate change, on marine biodiversity.This pioneering book is the first to address this important but neglected topic, which is likely to be the key challenge for marine scientists in the near future. After initially describing the complexity and diversity of the marine environment and the organisms which inhabit it, the book demonstrates the major effect of climate variability and global change on marine biodiversity at a range of spatial and temporal scales and of levels of organization within ecosystems. Building on his research on monitoring plankton populations, the author shows how the food chain in the oceans will be affected and its potential impact on fisheries. The book will serve as a textbook for all students of marine science and environmental change, but will also be accessible to the more general reader.