Deep ocean water

Deep ocean water (DOW) is the name for cold, salty water found deep below the surface of Earth's oceans. Ocean water differs in temperature and salinity. Warm surface water is generally saltier than the cooler deep or polar waters;[1] in polar regions, the upper layers of ocean water are cold and fresh.[2] Deep ocean water makes up about 90% of the volume of the oceans. Deep ocean water has a very uniform temperature, around 0-3 °C, and a salinity of about 3.5% or as oceanographers state as 35 ppt (parts per thousand).[3]

In specialized locations such as the Natural Energy Laboratory of Hawaii NELHA ocean water is pumped to the surface from approximately 900 metres (3000 feet) deep for applications in research, commercial and pre-commercial activities. DOW is typically used to describe ocean water at sub-thermal depths sufficient to provide a measurable difference in water temperature.

When deep ocean water is brought to the surface, it can be used for a variety of things. Its most useful property is its temperature. At the surface of the Earth, most water and air is well above 3 °C. The difference in temperature is indicative of a difference in energy. Where there is an energy gradient, skillful application of engineering can harness that energy for productive use by humans. Assuming the source of deep ocean water is environmentally friendly and replenished by natural mechanisms, it forms a more innovative basis for cleaner energy than current fossil-fuel-derived energy.

The simplest use of cold water is for air conditioning: using the cold water itself to cool air saves the energy that would be used by the compressors for traditional refrigeration. Another use could be to replace expensive desalination plants. When cold water passes through a pipe surrounded by humid air, condensation results. The condensate is pure water, suitable for humans to drink or for crop irrigation. Via a technology called Ocean thermal energy conversion, the temperature difference can be turned into electricity.

Cold-bed agriculture

During condensation or Ocean thermal energy conservation operations, the water does not reach ambient temperature, because a certain temperature gradient is required to make these processes viable. The water leaving those operations is therefore still colder than the surroundings, and a further benefit can be extracted by passing this water through underground pipes, thereby cooling agricultural soil. This reduces evaporation, and even causes water to condense from the atmosphere.[4] This allows agricultural production where crops would normally not be able to grow. This technique is sometimes referred to as "cold agriculture"[5] or "cold-bed agriculture".[6]


  1. ^ "Ocean Stratification". The Climate System. Columbia Univ. Retrieved 22 September 2015.
  2. ^ "The Hidden Meltdown of Greenland". Nasa Science/Science News. NASA. Retrieved 23 September 2015.
  3. ^ "Temperature of Ocean Water". UCAR. Retrieved 2012-09-05.
  4. ^ "Energinat - DOW Technologies - Cold Agriculture". Retrieved 14 July 2016.
  5. ^ West Hawaii Tech Pau Hana
  6. ^ "What is OTEC". OTEC News. the OTEC foundation. Retrieved 14 July 2016.

See also


Agwé (also spelt Goue, Agoueh, or Agive), is a loa who rules over the sea, fish, and aquatic plants, as well as the patron loa of fishermen and sailors in Vodou, especially in Haiti. He is considered to be married to Erzulie Freda and La Sirene. He goes by several titles, including koki la me ("Shell of the Sea"), koki dore ("Golden Shell"), "The Angel in the Mirror", "The Eel", and "The Tadpole in the Pond".


Alkalinity (from Arabic "al-qalī") is the capacity of water to resist changes in pH that would make the water more acidic. (It should not be confused with basicity which is an absolute measurement on the pH scale.) Alkalinity is the strength of a buffer solution composed of weak acids and their conjugate bases. It is measured by titrating the solution with a monoprotic acid such as HCl until its pH changes abruptly, or it reaches a known endpoint where that happens. Alkalinity is expressed in units of meq/L (milliequivalents per liter), which corresponds to the amount of monoprotic acid added as a titrant in millimoles per liter.

Although alkalinity is primarily a term invented by oceanographers, it is also used by hydrologists to describe temporary hardness. Moreover, measuring alkalinity is important in determining a stream's ability to neutralize acidic pollution from rainfall or wastewater. It is one of the best measures of the sensitivity of the stream to acid inputs. There can be long-term changes in the alkalinity of streams and rivers in response to human disturbances.

Amundsen Sea

The Amundsen Sea, an arm of the Southern Ocean off Marie Byrd Land in western Antarctica, lies between Cape Flying Fish (the northwestern tip of Thurston Island) to the east and Cape Dart on Siple Island to the west. Cape Flying Fish marks the boundary between the Amundsen Sea and the Bellingshausen Sea. West of Cape Dart there is no named marginal sea of the Southern Ocean between the Amundsen and Ross Seas. The Norwegian expedition of 1928–1929 under Captain Nils Larsen named the body of water for the Norwegian polar explorer Roald Amundsen while exploring this area in February 1929.The sea is mostly ice-covered, and the Thwaites Ice Tongue protrudes into it. The ice sheet which drains into the Amundsen Sea averages about 3 km (1.9 mi) in thickness; roughly the size of the state of Texas, this area is known as the Amundsen Sea Embayment (ASE); it forms one of the three major ice-drainage basins of the West Antarctic Ice Sheet.

Bahama Banks

The Bahama Banks are the submerged carbonate platforms that make up much of the Bahama Archipelago. The term is usually applied in referring to either the Great Bahama Bank around Andros Island, or the Little Bahama Bank of Grand Bahama Island and Great Abaco, which are the largest of the platforms, and the Cay Sal Bank north of Cuba. The islands of these banks are politically part of the Bahamas. Other banks are the three banks of the Turks and Caicos Islands, namely the Caicos Bank of the Caicos Islands, the bank of the Turks Islands, and wholly submerged Mouchoir Bank. Further southeast are the equally wholly submerged Silver Bank and Navidad Bank north of the Dominican Republic.


Benthos is the community of organisms that live on, in, or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.

Many organisms adapted to deep-water pressure cannot survive in the upper parts of the water column. The pressure difference can be very significant (approximately one atmosphere for each 10 metres of water depth).Because light is absorbed before it can reach deep ocean-water, the energy source for deep benthic ecosystems is often organic matter from higher up in the water column that drifts down to the depths. This dead and decaying matter sustains the benthic food chain; most organisms in the benthic zone are scavengers or detritivores.

The term benthos, coined by Haeckel in 1891, comes from the Greek noun βένθος "depth of the sea". Benthos is also used in freshwater biology to refer to organisms at the bottom of freshwater bodies of water, such as lakes, rivers, and streams. There is also a redundant synonym, benthon.

Canfield ocean

The Canfield Ocean model was proposed by geochemist Donald Canfield to explain the composition of the ocean in the middle to late Proterozoic. His theory has been coined the 'Canfield Ocean' and remains one of the cornerstone theories of ocean oxygen composition during that time.

In a seminal paper published in 1998 in Nature, Canfield argued that the ocean was anoxic and sulfidic during the time of the Boring Billion, and that those conditions affected the mineral deposition of iron-rich Banded iron formations (BIF). Prior to the Canfield Ocean theory, it was believed that the ocean became oxygenated during the Great Oxygenation Event. The presence of oxygen in the deep ocean made the formation of BIF impossible, which is seen in ocean sediment records. Conversely, the Canfield Ocean theory postulates that deep ocean water remained anoxic long after the Great Oxidation Event, and he argued that the euxinic conditions in the deep ocean ceased the deposition of BIF in ocean sediments.

Deep ocean minerals

Deep ocean minerals (DOM) are mineral nutrients (chemical elements) extracted from deep ocean water (DOW) found at ocean depths of between 250 and 1500 meters. DOW contains over 70 mineral nutrients and trace elements including magnesium (Mg), calcium (Ca) and potassium (K) in their bio ionic form. To extract these products, DOW is treated with micro filtration and reverse osmosis to desalinate and concentrate magnesium, other minerals and trace elements whilst eliminating the salt (sodium chloride).Although research about DOM is in its early stages, as it is a source of electrolytes that can help metabolize carbohydrate, proteins and fat plus maintain bone, teeth and muscle function, health benefits are possible.

The abundance of minerals and trace elements is also of note as deficiencies in macro minerals and micro trace elements can lead to premature aging, immune dysfunction and susceptibility to cardiovascular related diseases.

The minerals and trace elements (DOM) present in DOW have three important functions:

Provide the structure to our organs, tissues and bones – calcium, phosphorus, magnesium, fluorine and sulfur.

The electrolyte form facilitates body fluid activity in tissues to maintain fluid balance, acid-base balance, membrane permeability, tissue irritability (including nerve transmission and muscle contraction) - sodium, potassium, chloride, calcium and magnesium in blood, all present in DOMs.

Magnesium alone, potentially catalyses up to 600 enzyme and hormone reactions.

Great Australian Bight

The Great Australian Bight is a large oceanic bight, or open bay, off the central and western portions of the southern coastline of mainland Australia.

List of marine molluscs of Ireland

The list of marine marine molluscs of Ireland is a list of marine species that form a part of the molluscan fauna of Ireland.

Theer habitats include littoral, mesopelagic, pelagic, oceanic zone, benthic, deep ocean water and deep sea.

Natural Energy Laboratory of Hawaii Authority

The Natural Energy Laboratory of Hawaii Authority (NELHA) administers the Hawaii Ocean Science and Technology Park (HOST Park). NELHA was founded in 1974. At 870 acres (350 ha), HOST Park is perhaps the largest single green economic development project in the world solely devoted to growing a green economy. NELHA also administers a small site, 4 acres (1.6 ha), in Puna on the eastern side of the Island of Hawaii for geothermal research. The original mission was for research into the uses of Deep Ocean Water in Ocean thermal energy conversion (OTEC) renewable energy production and in aquaculture. It later added research into sustainable uses of natural energy sources such as solar energy.

Its administration offices are located in the HOST Park Keahole Point in the North Kona District.

The entrance is on the Hawaii Belt Road at coordinates 19°42′58″N 156°02′01″W, just south of the Kona International Airport. The main administration office is in the 4 acre research campus at the end of the road along the coastline on Keahole Point.

The laboratory was founded in 1974 with 345 acres (140 ha), associated with the University of Hawaii. Large pipelines pump cold sea water from a depth of 3,000 feet (910 m). For three months in 1979, a small amount of electricity was generated. A larger plant was constructed in the Almost $250M was spent on Ocean thermal energy conversion, but by 1991, the research shifted to other areas. The adjacent Science and Technology Park was merged into the facility, expanding it to 877 acres (355 ha). A neutrino detector was partially constructed in the 1990s called Project DUMAND.In 2002, 50 acres (20 ha) were leased to a commercial company which filters and bottles the water for sale in Japan.

The pipelines were broken in the October 15, 2006 earthquake, but one of the three has been repaired over two years later.

Makai Ocean Engineering, working with Lockheed Martin, restarted OTEC research. Aquaculture, biofuel from algae, solar thermal energy, solar concentrating and wind power are some of the 40 tenants.

Ocean current

An ocean current is a continuous, directed movement of sea water generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, shoreline configurations, and interactions with other currents influence a current's direction and strength. Ocean currents are primarily horizontal water movements.

Ocean currents flow for great distances, and together, create the global conveyor belt which plays a dominant role in determining the climate of many of the Earth’s regions. More specifically, ocean currents influence the temperature of the regions through which they travel. For example, warm currents traveling along more temperate coasts increase the temperature of the area by warming the sea breezes that blow over them. Perhaps the most striking example is the Gulf Stream, which makes northwest Europe much more temperate than any other region at the same latitude. Another example is Lima, Peru, where the climate is cooler, being sub-tropical, than the tropical latitudes in which the area is located, due to the effect of the Humboldt Current.

Ocean thermal energy conversion

Ocean thermal energy conversion (OTEC) uses the temperature difference between cooler deep and warmer shallow or surface seawaters to run a heat engine and produce useful work, usually in the form of electricity. OTEC can operate with a very high capacity factor and so can operate in base load mode.

Among ocean energy sources, OTEC is one of the continuously available renewable energy resources that could contribute to base-load power supply. The resource potential for OTEC is considered to be much larger than for other ocean energy forms [World Energy Council, 2000]. Up to 88,000 TWh/yr of power could be generated from OTEC without affecting the ocean’s thermal structure [Pelc and Fujita, 2002].

Systems may be either closed-cycle or open-cycle. Closed-cycle OTEC uses working fluids that are typically thought of as refrigerants such as ammonia or R-134a. These fluids have low boiling points, and are therefore suitable for powering the system’s generator to generate electricity. The most commonly used heat cycle for OTEC to date is the Rankine cycle, using a low-pressure turbine. Open-cycle engines use vapour from the seawater itself as the working fluid.

OTEC can also supply quantities of cold water as a by-product. This can be used for air conditioning and refrigeration and the nutrient-rich deep ocean water can feed biological technologies. Another by-product is fresh water distilled from the sea.OTEC theory was first developed in the 1880s and the first bench size demonstration model was constructed in 1926. Currently the world's only operating OTEC plant is in Japan, overseen by Saga University.

Ruditapes largillierti

Ruditapes largillierti is a saltwater clam, a marine bivalve mollusc in the family Veneridae, the Venus clams. Moderately large for genus (45–65 mm long), elongate and subrectangular, thick and solid, with smooth ventral margin.It has limited use to people and the seafood industry because it resides in very deep Ocean water and contains a very common pearl.


The seabed (also known as the seafloor, sea floor, or ocean floor) is the bottom of the ocean.

Underwater glider

An underwater glider is a type of autonomous underwater vehicle (AUV) that uses small changes in its buoyancy in order to move up and down in the ocean like a profiling float. Unlike a float, a glider uses wings to convert that vertical motion to horizontal, propelling itself forward with very low power consumption. While not as fast as conventional AUVs, gliders using buoyancy-based propulsion represent a significant increase in range and duration compared to vehicles propelled by electric motor-driven propellers, extending ocean sampling missions from hours to weeks or months, and to thousands of kilometers of range. Gliders follow an up-and-down, sawtooth-like profile through the water, providing data on temporal and spatial scales unavailable to previous AUVs, and much more costly to sample using traditional shipboard techniques. A wide variety of glider designs are in use by navies and ocean research organizations and typically cost US$100,000.

Wave base

The wave base, in physical oceanography, is the maximum depth at which a water wave's passage causes significant water motion. For water depths deeper than the wave base, bottom sediments and the seafloor are no longer stirred by the wave motion above.

West Antarctic Ice Sheet

The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West (or Lesser) Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains which lies in the Western Hemisphere. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea.

William H. Avery (engineer)

William Hinckley Avery (July 25, 1912 – June 26, 2004) was an influential aeronautical engineer. He designed the propulsion mechanism known as the ramjet, and was known for heading the Ocean Thermal Energy Conversion program which generates electricity from the temperature differential between shallow and deep ocean water.

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