Introduction to Marine Biology

Abstract

Life on Earth began in the sea which covers 71% of our planet’s surface and its algae have produced half of the atmospheric oxygen that we breathe. Under the influence of worldwide water currents, marine organisms are distributed as neuston, plankton, nekton, or benthos. This chapter summarizes the major horizontal and vertical gradients in chemical and physical conditions that determine ocean productivity of the sea which is driven by sunlight and algae. Seawater is a dense, viscous medium and so marine life has an array of adaptations to take advantage of this environment. We introduce the different marine phyla present, which have a far greater biodiversity than terrestrial fauna. This introduction explains the highly interdisciplinary nature of marine biology and demonstrates that pioneering research in the life sciences continues to use marine organisms, including evolutionary biology, molecular biology, developmental biology and physiology. The islands of Japan have attracted marine scientists worldwide due to an exceptional variety of conditions (from tropical corals to high latitude kelp forests, abyssal deep sea to shallow lagoons). This gives the region an unusually rich flora and fauna coupled by highly productive fisheries. This overview sets the scene for our book on Japanese marine life.