Deep-sea exploration

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**Historical Milestones in Deep-Sea Exploration:**
– Ferdinand Magellan’s depth measurement attempt in 1521.
– Antoine Risso’s species description in the Gulf of Genoa (1810-1827).
– Edward Forbes’ Abyssus theory on deep-sea life diversity (1843).
– Michael Sars’ discovery of diverse deep-sea fauna near Lofoten (1850).
– Sir John Ross’ discovery of deep-sea life at 2,000m depth (1818).

**Oceanographic Instrumentation and Advancements:**
– Instruments like sounding weights, bathyspheres, and sonar systems.
– The significance of the Challenger Expedition and its Baillie sounding machines.
– Jacques Piccard and Don Walsh’s Mariana Trench descent in 1960.
– Utilization of fiber optics, satellites, and manned submersibles for exploration.
– Ongoing advancements in deep-sea exploration technology.

**Unexplored Ocean Depths and Scientific Discoveries:**
Exploration beyond the continental shelf and the challenges faced by scientists.
– Notable discoveries by Laplace, Michael Sars, and Georg Ossian Sars.
– Contributions to understanding bathypelagic ecosystems and marine biodiversity.
– Scientific results, including findings in the Mid-Atlantic Ridge and hydrothermal vents.
– The ongoing quest to unveil the mysteries of the ocean depths.

**Deep-Sea Exploration Vehicles and Submersibles:**
– Atmospheric diving suits, bathyspheres, bathyscaphes, and manned submersibles like DSV Alvin.
– Various unmanned submersibles, including ROVs, AUVs, and hybrid ROVs.
– Materials, construction, and design considerations for deep-sea vessels.
– The role of pressure vessels, electronics casings, and materials like titanium.
– Notable deep-sea exploration vehicles and their contributions to underwater research.

**Impact, Importance, and Future of Deep-Sea Exploration:**
– The importance of deep-sea exploration in understanding global events and Earth’s final frontier.
– Record-breaking achievements and key players in undersea exploration.
– Environmental impacts of deep-sea mining and the balance between exploration benefits and consequences.
– Resources, references, and educational materials available for deep-sea exploration.
– The role of institutions, scientists, and technological advancements in shaping the future of deep-sea exploration.

Deep-sea exploration is the investigation of physical, chemical, and biological conditions on the ocean waters and sea bed beyond the continental shelf, for scientific or commercial purposes. Deep-sea exploration is an aspect of underwater exploration and is considered a relatively recent human activity compared to the other areas of geophysical research, as the deeper depths of the sea have been investigated only during comparatively recent years. The ocean depths still remain a largely unexplored part of the Earth, and form a relatively undiscovered domain.

The submersible's manipulator arm collecting a crab trap containing five galatheid crabs. This is an eel trap that has been modified to better catch deep sea fauna. Life on the Edge 2005 Expedition.

Scientific deep-sea exploration can be said to have begun when French scientist Pierre-Simon Laplace investigated the average depth of the Atlantic ocean by observing tidal motions registered on Brazilian and African coasts circa the late 18th or early 19th century. However, the exact date of his investigation is unknown. He calculated the depth to be 3,962 metres (12,999 ft), a value later proven quite accurate by echo-sounding measurement techniques. Later on, due to increasing demand for the installment of submarine cables, accurate measurements of the sea floor depth were required and the first investigations of the sea bottom were undertaken. The first deep-sea life forms were discovered in 1864 when Norwegian researchers Michael Sars and Georg Ossian Sars obtained a sample of a stalked crinoid at a depth of 3,109 m (10,200 ft).

Baillie sounding machine, an early gravity core sampler used by the Challenger expedition

From 1872 to 1876, a landmark ocean study was carried out by British scientists aboard HMS Challenger, a screw corvette that was converted into a survey ship in 1872. The Challenger expedition covered 127,653 kilometres (68,927 nmi), and shipboard scientists collected hundreds of samples and hydrographic measurements, discovering more than 4,700 new species of marine life, including deep-sea organisms. They are also credited with providing the first real view of major seafloor features such as the deep ocean basins.

The first instrument used for deep-sea investigation was the sounding weight, used by British explorer Sir James Clark Ross. With this instrument, he reached a depth of 3,700 m (12,139 ft) in 1840. The Challenger expedition used similar instruments called Baillie sounding machines to extract samples from the sea bed.[citation needed]

In the 20th century, deep-sea exploration advanced considerably through a series of technological inventions, ranging from the sonar system, which can detect the presence of objects underwater through the use of sound, to manned deep-diving submersibles. In 1960, Jacques Piccard and United States Navy Lieutenant Donald Walsh descended in the bathyscaphe Trieste into the deepest part of the world's oceans, the Mariana Trench. On 25 March 2012, filmmaker James Cameron descended into the Mariana Trench in Deepsea Challenger, and, for the first time, filmed and sampled the bottom.

Despite these advances in deep-sea exploration, the voyage to the ocean bottom is still a challenging experience. Scientists are working to find ways to study this extreme environment from the shipboard. With more sophisticated use of fiber optics, satellites, and remote-control robots, scientists hope to, one day, explore the deep sea from a computer screen on the deck rather than out of a porthole.

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