oceanography(redirected from Undersea Exploration)
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oceanography,study of the seas and oceans. The major divisions of oceanography include the geological study of the ocean floor (see plate tectonicsplate tectonics,
theory that unifies many of the features and characteristics of continental drift and seafloor spreading into a coherent model and has revolutionized geologists' understanding of continents, ocean basins, mountains, and earth history.
..... Click the link for more information. ) and features; physical oceanography, which is concerned with the physical attributes of the ocean water, such as currents and temperature; chemical oceanography, which focuses on the chemistry of ocean waters; marine biology, the study of the oceanic flora and fauna; and, in meteorology, the interaction between the atmosphere and the ocean.
Oceanography as a comprehensive study dates from the Challenger expedition (1872–76), directed by the naturalists C. W. Thomson, a Scot, and John Murray, a Canadian. The term oceanography became current through reports of the expedition edited by Murray, who later became a leader in the study of ocean sediment. The success of the Challenger expedition and the importance of ocean knowledge to shipping, fisheries, the laying of telegraph cables, and climatological studies led many nations to send out expeditions.
Universities and private individuals, as well as governments, have established institutions for the study of the ocean; there exist today about 250 such institutions. One of the earliest was the marine biological station at Naples (founded 1872), which stimulated the founding of many other seaside stations, some of which, e.g., the Scripps Institution of Oceanography at La Jolla, Calif., have enlarged their activities to include all fields of oceanographic research. Other notable institutions in the field include the Oceanographic Museum at Monaco (1910); the biological station of the Univ. of Oslo; the Woods Hole Oceanographic Institution at Woods Hole, Mass. (1930); and the Lamont-Doherty Geological Observatory of Columbia Univ (1949).
The first international oceanographic organization was the International Council for the Exploration of the Sea (1901). In 1966 the U.S. Congress created the National Council for Marine Resources and Engineering Development charged with exploring all aspects of ocean development, and authorized the National Science Foundation to sponsor sea-grant colleges analogous to the Dept. of Agriculture's sponsorship of land-grant colleges. Projects such as Conshelf, under Jacques Cousteau; Sealab, under the U.S. Navy; Tektite, a cooperative venture of the U.S. Dept. of the Interior and the National Aeronautics and Space Administration; Aquarius under the National Oceanic and Atmospheric Administration; and others have established temporary stations in oceans to see whether humans can live and work underwater for extended periods.
Modern deep-diving equipment has been improved to permit descents to very great depths, such as the U.S. bathyscaphe, Trieste II, which descended to 35,798 ft (10,294 m) in the Mariana TrenchMarianas trench,
or Marianas deep
, elongated depression on the Pacific Ocean floor, 210 mi (338 km) SW of Guam. It is the deepest known depression on the earth's surface, having been measured by various means at 35,760–36,089 ft
..... Click the link for more information. in 1960. Smaller, remote-controlled craft, such as the Jason, which was used to examine the sunken steamship Titanic, explore natural and humanmade underwater structures. Deep-diving craft (see submersiblesubmersible,
small, mobile undersea research vessel capable of functioning in the ocean depths. Development of a great variety of submersibles during the later 1950s and 1960s came about as a result of improved technology and in response to a demonstrated need for the capability
..... Click the link for more information. ) provide invaluable direct observations of the deep ocean bottom, mid-ocean ridges, and marine life. Recent oceanographic studies include drilling of the seafloor (see Deep Sea Drilling ProjectDeep Sea Drilling Project,
U.S. program designed to investigate the evolution of ocean basins by core drilling of ocean sediments and underlying oceanic crust. Funded by the National Science Foundation, the project was directed by the Joint Oceanographic Institution for Deep
..... Click the link for more information. ).
See M. G. Gross, Oceanography: A View of the Earth (1972); R. R. Ward, Into the Ocean World (1974); M. G. Gross, Oceanography (1990); R. A. Davis, Oceanography: An Introduction to the Marine Environment (1987, 2d ed. 1991); J. Cone, Fire Under the Sea (1992).
(Russian, okeanologiia, “oceanology”), the group of scientific disciplines dealing with physical, chemical, geological, and biological processes in the ocean. It is useful to combine the physics, chemistry, geology, and biology of the ocean into a single science because of the unity of the environment in which the diverse processes occur, the variety of interactions between these processes, and the common methodological basis for studying them (investigation of the transformation and exchange of energy and matter in the ocean). Moreover, the basic technical means of oceanographic research are the same for all these sciences. The main practical goals of oceanography are the safety and increased efficiency of surface and underwater navigation, the utilization of the biological, mineral, and energy resources of the ocean waters and bottom, and the improvement of weather forecasting techniques.
Oceanography is based primarily on (1) data from shipboard measurements—echo soundings of depths and determination of the ship’s position by astronomical methods and by using radio and special navigation earth satellites; (2) data from hydrological stations, where the temperature is measured at different depths and water samples are taken to determine its salinity and other chemical and optical characteristics; (3) measurements of surface currents (by the drift of ships and the bottle method) and deep currents (by revolving vanes suspended from anchored buoys and floats of neutral buoyancy with acoustic tracking); (4) visual estimates of wave action and its measurement with wave recorders; (5) special hydroacoustic measurements; (6) evaluation of water color and changes in its transparency according to the depth of visibility of a submerged white disc; and (7) characteristics of ice, bottom samples, and biological samples. Various measurements are also taken at shore and island stations, such as the level of the sea, tides, waves, and temperature.
The world oceanographic catalog (1973) contains data from about 200,000 hydrological stations (the data were obtained primarily in the northern hemisphere, in coastal waters, at maximum depths of 500–2,000 m, and during calm seasons) and from about 1,000 buoy stations measuring currents by instruments (most of the information on deep currents is obtained by computations based on the data from hydrological stations). Data from depth soundings are used to compile bathymetric maps of most of the ocean with a scale of 1:10,000,000; some seas and coastal waters have been described in greater detail. The descriptive data are the scientific basis for the work of hydro-graphic surveys in compiling navigation maps, tables, manuals, and sailing instructions.
Among the promising future methods of oceanographic research are continuous measurement by automatic buoy stations, measurements of the ocean surface by means of earth satellites (its relief, temperature, ice conditions, waves, and color), and the direct study of the shelf in underwater laboratories and of the ocean depths in hermetic underwater apparatus.
Physics of the ocean. Physical oceanography includes the hydrothermodynamics, acoustics, and optics of the ocean and the study of the ocean’s radioactivity (nuclear hydrophysics) and electromagnetic field. Marine hydrothermodynamics deals with the ocean’s heat and water balance and variations in level; its stratification according to temperature, salinity, and density; and its vertical thin-layer microstructure. It also deals with the ice conditions of the polar seas; synoptic, daily, seasonal, and annual fluctuations; the dynamics of wind-driven, internal, and gyroscopic waves (Rossby waves); inertial and tidal fluctuations and tsunami waves; turbulence and convection; and molecular processes on the surface of the ocean. Marine acoustics investigates the nature of propagation of sound waves (the chief means of underwater observation and communication) and natural noises. Marine optics studies the propagation, dispersal, and absorption of light in ocean waters.
The major problem of physical oceanography is to discover the principles of interaction between the ocean and the atmosphere—on a small scale, the formation of streams and the amount of movement, heat, and moisture on the surface of the ocean and on a large scale, the interrelationships between long-term global changes in the ocean and the atmosphere. Such data serves as the basis for long-term forecasting of weather and ocean changes and for climate theory.
Chemistry of the ocean. Chemical oceanography includes the hydrochemistry of ocean waters and the geochemistry of bottom sediments. Geochemistry deals with the quantitative investigation of the substances contained in solution and suspension in ocean waters, the elementary and isotopal composition of these substances, ion and molecular forms, and physicochemical and biochemical transformations. Special attention is devoted to the salinity of water, to dissolved oxygen and carbon dioxide, to solutions of compounds of phosphorus and nitrogen, and to silica and organic carbon. The main problems dealt with are the chemical balance of the ocean (its chemical exchange with the continents through river runoff and with the atmosphere and bottom), identification of different water masses, the origin and geochemical evolution of ocean waters, the extraction of valuable substances from seawater, and the chemical pollution of the ocean with petroleum, DDT, mercury, lead, and other substances. The geochemistry of bottom sediments studies their chemical composition, migrations, transformations, and the concentration of substances, the chemical processes of their diagenesis (conversion into rock), and the formation of sedimentary deposits of useful mineral products.
Geology of the ocean. Geological oceanography includes all the branches of geology, geophysics, and geochemistry as applied to the earth’s crust in the ocean. It deals with the relief of the ocean bottom; the composition and formation of contemporary sediments; the stratigraphy, lithology, mineralogy, and geochemistry of the sedimentary strata (using columns of bottom deposits obtained by bottom sampling tubes and core samples from ocean drilling); the petrography of magmatic bottom rocks; the structure of the layers of the earth’s crust (by seismic sounding and continuous seismic profiling); and heat flow across the bottom, gravitational and magnetic anomalies, and other geophysical characteristics. Geological oceanography focuses on the study of useful mineral products on the surface of the ocean bottom and beneath it (petroleum, gas, mineral placers, fer-romanganese-polymetalic concretions, metal-bearing sediments, phosphorites) and the formation of their deposits. It also devotes primary attention to the geological history of the oceans and global tectonics, including the formation of the mid-ocean mountain ranges, ocean plates, and deep-ocean trenches and the separation of the ocean bottom and continental drift.
Biology of the ocean. Biological oceanography deals with the ocean’s living inhabitants—plankton, nekton, benthos, and microorganisms. It deals with their classification, physiology, biology of development, biochemistry, ecology, biogeography, and evolutionary history; food interrelationships; the structure and functioning of biological communities; and the population dynamics of commercially valuable organisms. The oceanography of fisheries investigates the effect of ocean factors on the yield, number, and behavior of commercially valuable organisms and aims at working out the oceanographic principles of prediction. The major problems of this branch of oceanography are estimating the biomass and annual output of the most important types of organisms and controlling the biological productivity of the ocean—artificially increasing the output of valuable organisms (aquaculture).
A. S. MONIN
International organizations. The leading international organizations devoted to the study of the ocean are the Intergovernmental Oceanographic Commission of UNESCO, the International Council for the Exploration of the Sea, the International Hydrographic Bureau, the International Association of Physical Sciences of the Ocean, the Special Committee for Ocean Research, and the UN Food and Agricultural Organization.
National scientific institutions. The major oceanographic institutions in the USSR are the P. P. Shirshov Institute of Oceanology of the Academy of Sciences of the USSR, the State Oceanographic Institute, the arctic and antarctic institutes of the Central Board of the Hydrometeorological Service of the USSR, the Marine Hydrophysical Institute of the Academy of Sciences of the Ukrainian SSR, the All-Union Scientific Research Institute of Fisheries and Oceanography under the Ministry of the Fishing Industry of the USSR, the Institute of Biology of the Southern Seas of the Academy of Sciences of the Ukrainian SSR, and the Central Board of Navigation and Oceanography under the Ministry of Defense of the USSR. Important work in oceanography is being done at the American Woods Hole Oceanographic Institution in Massachusetts and Scripps Institution of Oceanography in California, the Canadian institutes of oceanography in Vancouver and Halifax, the British National Institute of Oceanography in Surrey, the French Oceanographic Institute in Brest, the Institut für Meereskunde at Kiel in the Federal Republic of Germany, the Oceanographic Museum in Monaco, and the Institute of Ocean Research in Japan.
Periodicals. The leading oceanographic journals are Okeanologiia (since 1961), Izvestiia AN SSSR: Fizika atmosfery i okeana (since 1965), Tr. Gos. okeanograficheskogo in-ta (since 1947), Meteorologiia i gidrologiia (since 1950), Tr. Morskogo gi-drqfizicheskogo in-ta (since 1948), Journal of Marine Research (New Haven, since 1937), Deep-sea Research (London, since 1953), Marine Observer (London, since 1924), International Hydrographic Bureau: International Hydrographic Bulletin (Monaco, since 1928), Bulletin hydrographique: Conseil permanent international pour l’exploration de la mer (Copenhagen, since 1908), Australian Journal of Marine and Freshwater Research (Melbourne, since 1950), Annual Report of the Fisheries Research Board of Canada (Ottawa, since 1937), Bulletin of the Scripps Institution of Oceanography (La Jolla, since 1925), Contributions From the Woods Hole Oceanographic Institution (Woods Hole, since 1933), Collected Reprints: National Institute of Oceanography (Wormly, since 1953), New Zealand Oceanographical Institute Collected Reprints (Wellington, since 1952), Deutsche hydrographische Zeichschrift (Hamburg, since 1948), Beitrage zur Meereskunde (Berlin, 1961), Kieler Meeresforschungen (Kiel, since 1937), Journal of the Oceanographical Society of Japan (Tokyo, since 1942), Japanese Journal of Geophysics (Tokyo, since 1954), and Journal of the Marine Biological Association of the United Kingdom (Plymouth, since 1887).