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Deep Sea Exploration
Deep Sea Exploration is investigation of physical, chemical, and biological conditions at the bottom of the ocean, for scientific and commercial purposes. The depths of the sea have been investigated with precision only during comparatively recent years; compared to the other areas of geological research, they still form a relatively unexplored domain.
Modern scientific study of the deep sea can be said to have begun when the French scientist Pierre Simon de Laplace calculated the average depth of the Atlantic Ocean from tidal motions registered on the Brazilian and African coasts. He determined this depth to be 3962 m (13,000 ft), a value proven quite accurate by later soundings. The first investigations of the sea bottom were undertaken because of the need for accurate soundings when laying submarine cables. That life exists at great depths was discovered in 1864, when Norwegian researchers sampled a stalked crinoid at a depth of 3109 m (10,200 ft). The most important knowledge of deep-sea conditions has been gained since 1870, beginning with the Challenger expedition sent out by the British government in 1872. It engaged in global oceanographic investigations for nearly four years, during which 715 new genera and 4417 new species of marine organisms were discovered.
Deep Sea Exploration - Instruments
The first instrument used for the investigation of the sea bottom was the sounding weight, with which British explorer Sir James Clark Ross reached a depth of 3700 m (12,140 ft) in 1840. The sounding weights used on the Challenger, called Baillie sounding machines, were provided with a tube into which a sample of the seabed was forced when the weight hit the bottom of the ocean. Also used on the Challenger were dredges and scoops, suspended on ropes, with which samples of the sediment and biological specimens of the seabed could be obtained.
A modern version of the Baillie sounding machine is the gravity corer. The corer consists of an open-ended tube with a lead weight and a trigger mechanism that releases the corer from its suspension cable when the corer is lowered over the seabed and a small weight touches the ground. The corer falls into the seabed and penetrates it to a depth of up to 10 m (33 ft). By lifting the corer, a long, cylindrical sample is extracted in which the structure of the seabed's layers of sediment is preserved. Samples of deeper layers can be obtained with a corer mounted in a drill. The drilling vessel JOIDES Resolution (see Ocean Drilling Program) is equipped to extract cores from depths of as much as 1500 m (4900 ft) below the ocean bottom.
Since World War II (1939-1945), echo-sounding techniques have been widely used to measure the depth of the sea bottom. Acoustic pulses are transmitted from the ship; the time registered for the reflection of the sound wave is a measure of the water's depth. By registering the time lapses between outgoing and returning signals continuously on paper tape, a continuous mapping of the seabed is obtained. Much of the ocean floor has been mapped in this way. Other instruments for deep-sea exploration are high-resolution television cameras, movie cameras, thermometers, pressure meters, flow meters, and seismographs. These instruments are either lowered to the sea bottom on long cables or attached to submersible buoys; they sometimes are provided with a sound source, making depth determination possible. Deep-sea currents can be determined by floats carrying an ultrasonic sound source so that their movements can be followed aboard the research vessel. Such vessels themselves require precise navigational instrumentation, such as satellite navigation devices, and special positioning systems that keep the vessel in a fixed position relative to sonar beacon on the bottom of the ocean.
Deep Sea Exploration - Submersibles
The American explorer Charles William Beebe was the first to observe marine species at depths that could not be reached by a diver. He and the engineer Otis Barton designed a spherical steel vessel called a bathysphere that could be lowered from a ship, suspended from a cable. In 1930 Beebe and Barton reached a depth of 435 m (about 1425 ft), and in 1934 a depth of 923 m (3028 ft). The danger of this submersible was that if the cable broke, the occupants could not return to the surface. With this in mind, Swiss physicist Auguste Piccard designed his first bathyscaphe, a navigable deep-sea vessel consisting of a pressure sphere that is kept buoyant by a float (a large container filled with gasoline). With this bathyscaphe, Piccard reached (1954) a depth of 4000 m (13,125 ft). In 1960 his son Jacques Piccard reached the record depth of 10,915 m (about 35,810 ft) in the Mariana Trench off the island of Guam, with Trieste (the second bathyscaphe built by Piccard in 1953).
Different countries around the world now employ a large number of occupied submersibles for deep-sea exploration. Among them is the American-built Alvin, which can dive to about 3600 m (about 12,000 ft), and which is equipped with underwater lights, cameras, a television system, and a mechanical manipulator to collect bottom samples. Unmanned, robot submersibles are also being used for underwater exploration. Capable of descending to depths of as much as 6000 m (20,000 ft), one such craft, called Argo, was used in 1985 to locate the wreck of the Titanic, and a smaller robot, called Jason, was used to explore the wreck.
Deep Sea Exploration - Results
The first large deep-sea exploration using occupied submersibles was the French-American Mid-Ocean Undersea Study (FAMOUS) project. In 1974 the Alvin (operated by the Woods Hole Oceanographic Institution), the French bathyscaphe Archimède, and the French diving saucer Cyane, assisted by support ships and the Glomar Challenger, explored the great rift valley of the Mid-Atlantic Ridge, southwest of the Azores. Geologists consider the rift valley as the separation between the Eurasian plate and the North American plate of the earth's crust, and it constitutes one of the many sites in the ocean bottom where molten rock oozes forth to form new crust. About 5200 photographs of the region were taken, and samples of relatively young solidified magma were found on each side of the central fissure of the rift valley, giving additional proof that the seafloor spreads at this site at a rate of about 2.5 cm (about 1 in) per year (see Plate Tectonics). In a series of dives in 1979 and 1980 into the Galápagos Rift, off the coast of Ecuador, French, Mexican, and U.S. scientists found chimney like vents, nearly 9 m (nearly 30 ft) high and about 3.7 m (about 12 ft) across, discharging a mixture of hot water (up to 300° C/570° F) and dissolved metals in dark, smoke like plumes (see Hydrothermal Vent). These hot springs play an important role in the formation of deposits that are enriched in copper, nickel, cadmium, chromium, and uranium.
Deep Sea Explorations - Time-Line
Ocean Diving Begins
Around this time, coastal cultures like those in Greece and China begin diving into the sea as a source of food gathering, commerce, and possibly even warfare.
First Sailing Vessels
The ancient Egyptians develop the first sailing vessels. These vessels were probably only used for sailing in the eastern Mediterranean and near the mouth of the Nile river.
First Sea Routes
In search of tin and other resources, the ancient Phoenicians develop sea routes around the Mediterranean and into the Red Sea and Indian Ocean. They make it as far as Africa by 590 B.C. They also reach England by sailing along the western European coast.
First Crude Diving Bell
The Greek philosopher Aristotle mentions the use of a sort of crude, air-supply diving bell.
Viking Expeditions Begin
The Vikings begin to explore and colonize Iceland, Greenland, and Newfoundland. They are among the first to use the North Star to determine their latitude.
September 20, 1519
First Circumnavigation of the World
Ferdinand Magellan and his fleet depart Portugal to begin a daring voyage of discovery. The fleet would become the first sail around the world. Magellan does not live to see their accomplishment. He dies on the Island of Mactan in the Philippines in 1521 from the poison arrows of the local natives.
First True Diving Bell
Guglielmo de Lorena invents the first true diving bell. The apparatus rested on diver’s shoulders and had much of its weight supported by slings. The bell provided enough air for the diver to breathe for about a one-hour dive.
First Plans for a Submarine
An English mathematician named William Bourne draws up the first known plans for an underwater boat. These plans call for a leather-covered wooden frame craft that would be rowed from the inside. There is no evidence to suggest that this craft was ever built.
Dutch physician Cornelis Drebbel builds the world's first submarine. The boat is made of wood reinforced with iron and covered with leather. Inside, 12 oarsmen are seated six on each side. They row with oars that stick out the sides through tight fitting leather sleeves to keep the water out. Drebbel makes several trips in his submarine in the Thames River near London at a depth of about 12 or 15 feet.
First Air-replenished Diving Bell
The English astronomer Edmund Halley develops a diving bell in which the atmosphere in the bell can be replenished by sending weighted barrels of air down from the surface.
First Waterproof Suit
Chevalier de Beauve, a guard in the Navy, develops a waterproof suit with lead shoes. Air is supplied from the surface by two leather tubes fastened to the helmet.
First Enclosed Diving Device
Englishman John Lethbridge develops a completely enclosed, one-man diving dress. The device is made from a reinforced, leather-covered barrel of air, equipped with a glass porthole for viewing, and two arm holes with watertight sleeves.
August 26, 1768
First Voyage of Endeavour
Lieutenant James Cook leaves the port of Plymouth, England on a voyage to observe a transit of the planet of Venus across the Sun. During this and two voyages to follow, Cook would explore and map the Pacific Ocean. He was the first to use a chronometer to to accurately determine his longitude at sea.
First Practical Diving Helmet
The French scientist Sieur Freminet invents a helmet-hose diving apparatus, in which air is pumped from the surface with an egg-shaped reservoir. The air reaches the diver through a hose attached to the helmet. This system provided a constant supply of air to the diver. With this device, Freminet is able to stay submerged at a depth of 16 meters for up to 1 hour.
First True Diving Bell
American John Smeaton incorporates several improvements to the diving bell. He builds the bell made from cast iron and is the first to use an efficient hand-operated pump to sustain the air supply via a hose. An air reservoir system and non-return valves to keep air from being sucked back up the hoses when the pump stops.
First Diving Suit
German mechanic Karl Heinrich Klingert creates a device, which is the first to be called a "diving suit”. It consists of a jacket and trousers made of waterproof leather, a helmet with a porthole, and a metal front. It is linked to a turret with an air reservoir. The reservoir cannot replenish itself, so the suit has a limited dive time duration.
Robert Fulton, inventor of the steamboat, builds an early submarine called The Nautilus. This cigar-shaped craft is made of wood over iron plates, and uses a horizontal rudder to control the up-and-down movement of the submarine. This rudder system is still in use today.
First use of Scuba
Englishman William H. James designs a self-contained underwater breathing apparatus, or scuba. In James' design, the diver wears a helmet and carries a supply of compressed air in a cast-iron belt fastened around the waist. This device allows the diver to remain underwater for up to an hour.
December 27, 1831
Voyage of the H.M.S. Beagle
English naturalist Charles Darwin departs England aboard the H.M.S. Beagle. The goal of the expedition is to perform a survey Patagonia and Tierra del Fuego. Darwin studies the plants and animals at each new stop. He discovers many unique species on the Galapagos Islands off the coast of Peru in South America. These discoveries lead to his groundbreaking theory of evolution. In his book, The Origin of Species, Darwin suggests that the deep ocean may be a sanctuary for living fossils.
First Practical Diving Suit
Augustus Siebe, a German instrument maker, refines and improves previous diving suit designs and introduces the "Siebe Improved Diving Dress". This diving suit is the true predecessor to the famous deep-sea diving suit familiar to everybody today. The improved design allowed a greater freedom of movement for the diver and would be used for over a century.
December 21, 1872
Voyage of the H.M.S. Challenger
Intrigued by the earlier work by Charles Darwin aboard the Beagle, the H.M.S. Challenger sails from Portsmouth, England and begins a four-year around the world. During the voyage, scientists test the salinity, temperature and density of the seawater. Information is also collected about ocean currents, sediment, and meteorology. The crew discovers underwater mountain chains and hundreds of species previously unknown. This research is eventually consolidated into a fifty-volume research report known as The Challenger Report. This research forms the basis of modern oceanography.
Scripps Institution of Oceanography becomes affiliated with the University of California. Scripps is one of the world's leading marine research centers and is located in La Jolla, California, just north of San Diego.
Woods Hole Oceanographic Institution
In Cape Cod, Massachusetts, the Woods Hole Oceanographic Institution is founded. Woods Hole would become one of the world's leading oceanographic research institutions.
First Deep Ocean Dive
William Beebe and Otis Barton descend in a tethered sphere to a depth of a half-mile, where they find a previously unseen world of bizarre, luminescent creatures.
Fishermen off the coast of South Africa pull up a five-foot fish identified as a coelacanth, a living fossil thought to be extinct since the days of the dinosaurs. Since then, several live coelacanths have been discovered in African coastal waters.
First Modern Scuba
Explorers Jacques Cousteau and Emile Gagnan develop the first scuba that allows divers to stay underwater for extended periods and more effectively explore the ocean realm.
First Untethered Deep Water Craft
Swiss physicist Auguste Piccard dives in his newly designed vehicle known as a bathyscaph. It is the first untethered craft to carry people into the oceans deep waters. His son, Jacques Piccard, would soon take the bathyscaph to the deepest point in the ocean.
Deepest Ocean Point Found
The British ship Challenger II bounces sound waves off the ocean bottom and locates what appears to be the sea's deepest point. Nearly seven miles down, it is subsequently named the Challenger Deep. Located off the coast of the Marianas Islands in the Pacific Ocean, the site is known today as the Marianas Trench. If you could put Mount Everest on the ocean floor in the Marianas Trench, its summit would lie about a mile below the ocean sirface.
Mid-Atlantic Ridge Discovered
Through the use of echo soundings, Marie Tharp discovers that the Mid-Atlantic Ridge conceals a long rift valley, which turns out to be part of a hidden volcanic mountain range that extends the entire length of the Atlantic Ocean.
January 23, 1960
Deepest Ocean Dive
Jacques Piccard, son of explorer August Piccard, and two other men descend into the ocean to a depth of 35,797 feet, nearly seven miles. They make the trip in the Trieste, a sturdy underwater vehicle known as a bathyscaphe. Trieste was designed by Piccard and built several years earlier. The divers discover fish and other amazing deep-sea life at these tremendous depths.
First Underwater Habitat
Several experiments are conducted whereby people live in underwater habitats. The researchers leave the habitat for exploration and return again for food, sleep, and relaxation. The habitats are supplied by compressed air from the surface. In the first such experiment, Conshelf (Continental Shelf) One, Jacques Cousteau and his team spend seven days under 33 feet of water near Marseilles, France, in a habitat they name Diogenes.
First Underwater Robot
The Navy develops Halibut, a submarine that can lower miles of cables bearing lights, cameras, and other gear to spy on enemy armaments and materiel lost on the bottom of the sea.
The National Oceanic and Atmospheric Administration is established. This U.S. Government agency is responsible for all U.S. weather and climate forecasting, monitoring and archiving of ocean and atmospheric data, management of marine fisheries and mammals, mapping and charting of all U.S. waters, coastal zone management, and research and development in all of these areas.
Hydrothermal Vents Discovered
Scientists aboard the deep sea submersible, Alvin, discover and document incredible deep-sea hydrothermal vents in the eastern Pacific Ocean. Scalding hot water pouring from these vents enriches the water with nutrients and provides food for bacteria and a host of other organisms. This discovery rocks the scientific community because, for the first time, an ecosystem was found that thrives without the energy of the Sun. Instead of relying on sunlight and photosynthesis, these ecosystems rely on chemicals energy through a process known as chemo-synthesis.
July 20, 1985
Famed treasure hunter Mel Fisher finds the wreck of the Atocha off the coast of the Florida Keys. Lying in only 55 feet of water, the Atocha would soon yield the biggest treasure ever recovered from a shipwreck. The discovery would come at a price, however. Mel lost his son, Dirk, Dirk's wife, and another crew member in a tragic boating accident in 1975 while searching for the Atocha.
September 1, 1985
Dr. Robert Ballard, with the help of a tiny robotic submarine named Jason, discovers the wreck of the Titanic. The wreck is found in 12,500 feet (two and a half miles) of water about 375 miles off the coast of Newfoundland in Canada. Titanic is found in two separate pieces, dashing any hopes of one day raising the mighty ship.