Oceanography, also called marine science, is the study of the ocean. Its goal is to discover unifying principles that can explain data measured in ocean waters, in the organisms that live in the ocean, and on the land surrounding the ocean. Oceanography is a broad subject, drawing on techniques and theories from biology, chemistry, physics, mathematics, geology, and engineering. Oceanography is usually divided into four different areas of research. Marine biology or biological oceanography focuses on life (animals, plants, and bacteria) in the ocean. Chemical oceanography studies the substances that are dissolved in the ocean. Physical oceanography attempts to understand the movement of water and the relationships between oceans and the atmosphere (mass of air surrounding Earth). Marine geology is directed at understanding geological features of the ocean floor, such as the composition of the seafloor and the movement of tectonic plates (moving plates of Earth's crust).

History of Oceanography