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Underwater
An underwater environment is a environment of, and immersed in, liquid water in a natural or artificial feature (called a Water, body of water), such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer. Some characteristics of the underwater environment are universal, but many depend on the local situation. Liquid water has been present on Earth for most of the History of Earth, history of the planet. The underwater environment is thought to be the place of the origin of life on Earth, and it remains the ecological region most critical to the support of life and the natural habitat of the majority of living organisms. Several branches of science are dedicated to the study of this environment or specific parts or aspects of it. A number of human activities are conducted in the more accessible parts of the underwater environment. These include research, underwater diving for work or recreation, and underwater warfare with submarines. It is hostile to humans in many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonar
Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects on or under the surface of the water, such as other vessels. "Sonar" can refer to one of two types of technology: ''passive'' sonar means listening for the sound made by vessels; ''active'' sonar means emitting pulses of sounds and listening for echoes. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. Acoustic location in air was used before the introduction of radar. Sonar may also be used for robot navigation, and sodar (an upward-looking in-air sonar) is used for atmospheric investigations. The term ''sonar'' is also used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from very low ( infrasonic) to e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submersibles
A submersible is an underwater vehicle which needs to be transported and supported by a larger ship, watercraft or dock, platform. This distinguishes submersibles from submarines, which are self-supporting and capable of prolonged independent operation at sea. There are many types of submersibles, including both human-occupied vehicles (HOVs) and uncrewed craft, variously known as remotely operated vehicles (ROVs) or unmanned underwater vehicles (UUVs). Submersibles have many uses including oceanography, underwater archaeology, ocean exploration, tourism, underwater work, equipment maintenance and underwater search and recovery, recovery and underwater videography. History The first recorded self-propelled underwater vessel was a small oar-powered submarine conceived by William Bourne (mathematician), William Bourne (c. 1535 – 1582) and designed and built by Dutch inventor Cornelis Drebbel in 1620, with two more improved versions built in the following four years.Konstam (201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Challenger Deep
The Challenger Deep is the List of submarine topographical features#List of oceanic trenches, deepest known point of the seabed of Earth, located in the western Pacific Ocean at the southern end of the Mariana Trench, in the ocean territory of the Federated States of Micronesia. The General Bathymetric Chart of the Oceans, GEBCO Gazetteer of Undersea Feature Names indicates that the feature is situated at and has an approximated maximum depth of below sea level. A subsequent study revised the value to at a 95% confidence interval. However, both the precise geographic location and depth remain ambiguous, with contemporary measurements ranging from . The depression is named after the British Royal Navy survey ships , whose Challenger expedition, expedition of 1872–1876 first located it, and HMS Challenger (1931), HMS ''Challenger II'', whose expedition of 1950–1952 established its record-setting depth. The first descent by any vehicle was conducted by the United States N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mariana Trench
The Mariana Trench is an oceanic trench located in the western Pacific Ocean, about east of the Mariana Islands; it is the deep sea, deepest oceanic trench on Earth. It is crescent-shaped and measures about in length and in width. The maximum known depth is at the southern end of a small slot-shaped valley in its floor known as the Challenger Deep. The deepest point of the trench is more than farther from sea level than the peak of Mount Everest. At the bottom of the trench, the water column above exerts a pressure of , more than 1,071 times the standard atmospheric pressure at sea level. At this pressure, the density of water is increased by 4.96%. The temperature at the bottom is . In 2009, the Mariana Trench was established as a National monument (United States), US National Monument, Mariana Trench Marine National Monument. One-celled organisms called monothalamea have been found in the trench at a record depth of below the sea surface by researchers from the Scrip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean
The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean, Antarctic/Southern, and Arctic Ocean),"Ocean." ''Merriam-Webster.com Dictionary'', Merriam-Webster, https://www.merriam-webster.com/dictionary/ocean . Accessed March 14, 2021. and are themselves mostly divided into seas, gulfs and Lists of bodies of water#Seawater bodies, subsequent bodies of water. The ocean contains 97% of Water distribution on Earth, Earth's water and is the primary component of Earth's hydrosphere, acting as a huge Ocean heat content, reservoir of heat for Earth's energy budget, as well as for its carbon cycle and water cycl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Ocean
The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian, Antarctic/Southern, and Arctic Ocean),"Ocean." ''Merriam-Webster.com Dictionary'', Merriam-Webster, https://www.merriam-webster.com/dictionary/ocean . Accessed March 14, 2021. and are themselves mostly divided into seas, gulfs and subsequent bodies of water. The ocean contains 97% of [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering Water distribution on Earth, 70.8% of Earth's crust. The remaining 29.2% of Earth's crust is land, most of which is located in the form of continental landmasses within Earth's land hemisphere. Most of Earth's land is at least somewhat humid and covered by vegetation, while large Ice sheet, sheets of ice at Polar regions of Earth, Earth's polar polar desert, deserts retain more water than Earth's groundwater, lakes, rivers, and Water vapor#In Earth's atmosphere, atmospheric water combined. Earth's crust consists of slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's outer core, Earth has a liquid outer core that generates a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Ocean
The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for separating the New World of the Americas (North America and South America) from the Old World of Afro-Eurasia (Africa, Asia, and Europe). Through its separation of Afro-Eurasia from the Americas, the Atlantic Ocean has played a central role in the development of human society, globalization, and the histories of many nations. While the Norse colonization of North America, Norse were the first known humans to cross the Atlantic, it was the expedition of Christopher Columbus in 1492 that proved to be the most consequential. Columbus's expedition ushered in an Age of Discovery, age of exploration and colonization of the Americas by European powers, most notably Portuguese Empire, Portugal, Spanish Empire, Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River
A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it runs out of water, or only flow during certain seasons. Rivers are regulated by the water cycle, the processes by which water moves around the Earth. Water first enters rivers through precipitation, whether from rainfall, the Runoff (hydrology), runoff of water down a slope, the melting of glaciers or snow, or seepage from aquifers beneath the surface of the Earth. Rivers flow in channeled watercourses and merge in confluences to form drainage basins, or catchments, areas where surface water eventually flows to a common outlet. Rivers have a great effect on the landscape around them. They may regularly overflow their Bank (geography), banks and flood the surrounding area, spreading nutrients to the surrounding area. Sedime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abyssal Plain
An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface. They are among the flattest, smoothest, and least explored regions on Earth. Abyssal plains are key geologic elements of oceanic basins, the other elements being an elevated mid-ocean ridge and flanking abyssal hills. The creation of the abyssal plain is the result of the spreading of the seafloor (plate tectonics) and the melting of the lower oceanic crust. Magma rises from above the asthenosphere (a layer of the upper mantle), and as this basaltic material reaches the surface at mid-ocean ridges, it forms new oceanic crust, which is constantly pulled sideways by spreading of the seafloor. Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt. Much of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctic Ocean
The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea. It has also been described as an estuary of the Atlantic Ocean. It is also seen as the northernmost part of the all-encompassing world ocean. The Arctic Ocean includes the North Pole region in the middle of the Northern Hemisphere and extends south to about 60°N. The Arctic Ocean is surrounded by Eurasia and North America, and the borders follow topographic features: the Bering Strait on the Pacific side and the Greenland Scotland Ridge on the Atlantic side. It is mostly covered by sea ice throughout the year and almost completely in winter. The Arctic Ocean's surface temperature and salinity vary seasonally as the ice cover melts and freezes; its salinity is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Ocean
The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the world ocean, generally taken to be south of 60th parallel south, 60° S latitude and encircling Antarctica. With a size of , it is the second-smallest of the five principal oceanic divisions, smaller than the Pacific Ocean, Pacific, Atlantic Ocean, Atlantic and Indian Ocean, Indian oceans, and larger than the Arctic Ocean. The maximum depth of the Southern Ocean, using the definition that it lies south of 60th parallel, was surveyed by the Five Deeps Expedition in early February 2019. The expedition's multibeam sonar team identified the deepest point at 60° 28' 46"S, 025° 32' 32"W, with a depth of . The expedition leader and chief submersible pilot Victor Vescovo, has proposed naming this deepest point the "Factorian Deep", based on the name of the crewed submersible ''DSV Limiting Factor'', in which he successfully visited the bottom for the first time on February 3, 2019 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
