The oceans are part of the thin, outer shell of the Earth and marine science is the study of this envelope, from the deep sea to shallow coastal oceans: their biology, chemistry, geology and physics together make marine science a richly inter-disciplinary science. The oceans are dynamic and vast, they contain most of the Earth's water and carbon and surface heat, and much of its biomass, but they do not operate alone. In conjunction with the atmosphere, continents and ice (cryosphere), they form a working machine, driven mostly by energy derived from the sun and the Earth’s interior.

Marine Scientists focus their work on both practical or applied problems and basic scientific questions. The oceans provide both bounty and peril; they provide a wealth of food, a vast water supply reservoir and are the source of most of the heat and carbon used in our climate system, they are the source of ½ the oxygen our biosphere needs; they also spawn large storms and hurricanes, and transmit energy over great distances as tsunamis, all of which endanger coastal populations, which are a significant fraction of the Earth’s total population.