Synopsis The environmental science is a fast emerging interdisciplinary branch of science which is now introduced at both undergraduate and postgraduate levels in pure and applied sciences. The environmental biology or ecology is the basic study which any environmental scientist has to be acquainted with. As ecology is related to all branches of biology a clear understanding of ecology assumes great significance. Two main groups of ecology can be classified as terrestrial and aquatic ecology. Relatively less attention has however been paid to aquatic ecology. Aquatic ecology is a fascinating group dealing with fresh water, estuarine and marine ecosystem. The present book covers all the aspects of aquatic ecology. The book contains ten chapters with a special focus on marine ecosystem, productivity in aquatic habitats, water pollution aquaculture, and methodology to study aquatic eco-systems.