Biology is a natural science which focuses on life and living organisms. It attempts to study their physical structure, physiological mechanisms, development and evolution. The marine life or organisms living in the seas and oceans are studied under marine biology. Some of the common habitats of marine life are coral reefs, seagrass meadows, kelp forests, tidepools, deep sea trenches and surroundings of seamounts and thermal vents. Marine ecosystems exhibit an inverted energy pyramid structure. Microorganisms such as phytoplankton, zooplankton, ctenophores, molluscs, arthropods, etc. are at the bottom of the pyramid while large organisms such as whales and sharks are at the top. Marine life is studied under various sub branches of biology such as phycology, ichthyology and invertebrate zoology. The topics included in this book on biology of marine life are of utmost significance and bound to provide incredible insights to readers. It elucidates new techniques and their applications in a multidisciplinary approach. This book aims to serve as a source of information for students and experts alike and contribute to the growth of the discipline.