The science of the sea; including physical oceanography, marine chemistry, marine geology, and marine biology. The need to know more about the impact of marine pollution and possible effects of the exploitation of marine resources, together with the role of the ocean in possible global warming and climate change, means that oceanography is an important scientific discipline. Improved understanding of the sea has been essential in such diverse fields as fisheries conservation, the exploitation of underwater oil and gas reserves, and coastal protection policy, as well as in national defense strategies. The scientific benefits include not only improved understanding of the oceans and their inhabitants, but important information about the evolution of the Earth and its tectonic processes, and about the global environment and climate, past and present, as well as possible future changes. Climate history Marine sediments Maritime meteorology The traditional basis of modern oceanography is the hydrographic station. Hydrographic studies are still carried out at regular intervals, with the research vessel in a specific position. Seawater temperature, depth, and salinity can be measured continuously by a probe towed behind the ship. The revolution in electronics has provided not only a new generation of instruments for studying the sea but also new ways of collecting and analyzing the data they produce. Computers are employed in gathering and processing data in all fields, and are also used in the creation of mathematical models to aid in understanding. Much information can also be gained by remote sensing using satellites, which are also a valuable navigational aid. These provide data on sea surface temperature and currents, and on marine productivity. Satellite altimetry gives information on wave height and winds and even bottom topography (because this affects sea level). Deep-sea cameras and submersibles now permit visual evidence of creatures in remote depths.Hydrography Marine ecology Seawater Since the early 1900s, all recorded ocean depths have been incorporated in the General Bathymetric Chart of the Ocean. The amount of data available increased greatly with the introduction of continuous echo sounders; subsequently, side-scan sonar permitted very detailed topographical surveys to be made of the ocean floor. The features thus revealed, in particular the midocean ridges (spreading centers) and deep trenches (subduction zones), are integral to the theory of plate tectonics. An important discovery made toward the end of the twentieth century was the existence of hydrothermal vents, where hot mineral-rich water gushes from the Earth's interior. The deposition of minerals at these sites and the discovery of associated ecosystems make them of potential economic as well as great scientific interest. Marine geology Mid-Oceanic Ridge |
