Oceanography

The ocean is the largest habitat on the planet, and it houses an astounding array of life, from microbes to whales. Oceanography is the branch of Earth science that studies the Earth’s oceans. It is the systematic scientific study of the oceans and deep sea with the goal of understanding their processes and phenomena. The relationship of oceans with other aspects of the Earth’s environment is also highlighted in oceanographic studies. Biology, chemistry, geology, and physics together make oceanography a richly interdisciplinary science. Although they contain most of the Earth’s water, carbon, surface heat, and biomass, the oceans do not operate alone. Together with the atmosphere, continents, and ice-cover, they form a working platform, driven mostly by energy from the sun.

Earth science has four main components: hydrosphere, solid earth, atmosphere, and biosphere. Water at the Earth’s surface, or near it, is termed the hydrosphere. It includes oceans, water vapor, ground water, lakes, rivers, and polar icecaps. The water distribution in the hydrosphere is as follows: oceans—97.54 percent, icecaps—1.81 percent, groundwater—0.63 percent, others—0.02 percent.

Oceanography is studied in order to understand how oceans operate and how they interact with other aspects of the Earth system. Oceans are a vast source of food for the world’s population. The oceans hold an enormous reservoir of minerals, as well as fossil fuels for potential for energy development.

Four Branches of Oceanography

The study of oceanography may be divided into four branches: biological, chemical, geological and physical. Biological oceanography is the study of marine organisms and productivity, life cycles, and ecosystems. Biological oceanography spans studies of all levels of biological organization, from single genes to organisms to their population dynamics. It includes studies on how organisms interact with and contribute to essential global processes.

Chemical oceanography deals with water chemistry and biogeochemical cycling. It is the study of everything about the chemistry of the ocean and is based on the distribution and dynamics of elements, isotopes, atoms, and molecules. This ranges from fundamental physical, thermodynamic, and kinetic chemistry to two-way interactions of ocean chemistry with biological,geological, and physical processes. It encompasses both inorganic and organic chemistry.

Chemical oceanography includes processes that occur on a wide range of spatial and temporal scales; from global to regional to local to microscopic spatial dimensions, and timescales from geological epochs to glacial-interglacial to millennial, decadal, interannual, seasonal, diurnal, and all the way to microsecond time scales. Geological oceanography is the study of the geology of the ocean floor including plate tectonics, ocean basin geology, and ocean history, while physical oceanography studies the ocean’s physical attributes, including temperature-salinity structure, water properties, mixing, waves, tides, and currents.

Physical oceanography studies the physics of the ocean, the kinds of motions of water, the speed, and the direction of the water. Physical oceanography is the study of the fluid motions of the ocean. Its goal is to understand the processes at all time- and space-scales, to simulate these processes and to make predictions, if possible. Physical oceanographers are also interested in determining how much heat enters the ocean and where the heat is transferred. These diverse topics reflect many basic disciplines (biology, chemistry, geology, meteorology, and physics) that oceanographers utilize to further knowledge of the world ocean and understanding of processes within it. Oceanography is born out of scientific curiosity and aids in the understanding of marine resources and their impact on humans and global climate changes. The aim of oceanography is an understanding of the oceanic circulation and the distribution of heat in it, appreciation of the interaction of oceans with the atmosphere, and the role they play in maintaining the climate.

The origin of the ocean basins is traced to many theories. In the cosmic school of thought, it is believed that the moon blew out of the Earth, only to be caught by the Earth’s gravity as a natural satellite. The hole is said to be located in the region of the Pacific Ocean. This idea was popular until the evidence supporting the theory of plate tectonics gained support. In the plate tectonics theory, oceans are produced as diverging plates open the space between them. Triple junction theory states that a crack begins on a continental plate, joining cracks from three different directions, until a series of these cracks eventually separates the plate and produces a proto-ocean.

The supercontinent cycle theory notes that the breaking apart of Pangaea has occurred several times with the production of supercontinents over and over, and with oceans breaking up the spaces between them. The most viable hypothesis for explaining the origin of the ocean water is that it is from the interior of the Earth. Earth’s distance from the sun and its mass were obviously crucial in the formation of the oceans.

The major oceans are the Pacific, Atlantic, Indian, and Artic oceans. The Pacific Ocean is the largest and deepest, and covers 50 percent of the surface area of the world’s oceans. Marine environments could be classified by light and location. Inhabitants of marine zones include planktons, nektons, and benthos. Water is found everywhere on Earth and is the only known substance that can naturally exist as a gas, liquid, and solid, within the relatively small range of temperatures and pressures found at the Earth’s surface. Oceans contain nearly 98 percent of all the water on or near the surface of the Earth. The residence time of ocean water is about 37,000 years. Changes to the coastal environment occur from the movement of ocean waters against the shore. Surface ocean currents are broad, slow, drifts of surface water, set in motion by the prevailing winds, but rarely causing erosion deeper than 164–328 ft. (50–100 m). The gases that make up the oceans were trapped within the Earth as it formed. The major trapped volatile was water; others included nitrogen and carbon (IV) oxide. Seventy-one percent of Earth’s surface is covered by water, and 29 percent of the surface area is land.