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Sponge Diving
Sponge diving is underwater diving to collect soft natural sponges for human use. Background Most sponges are too rough for general use due to their structural spicules composed of calcium carbonate or silica. But two genera, ''Hippospongia'' and ''Spongia'', have soft, entirely fibrous skeletons. These two genera are most commonly used by humans. It is unknown when exactly the sponge became an article of use. In Ancient Greek writings, Homer and Plato mentioned the sponge as an object used for bathing. Through trading, Europeans used soft sponges for many purposes including padding for helmets, portable drinking utensils and municipal water filters. Until the invention of synthetic sponges, they were used as cleaning tools, applicators for paints and ceramic glazes, and discreet contraceptives. However, by the mid-20th century, over-fishing had brought both the animals and the industry close to extinction. Many objects with sponge-like textures are now made of substances not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sponge Diver John M
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals. Etymology The term ''sponge'' derives from the Ancient Greek word ( 'sponge'). Overview Sponges are similar to other animals in that they are multicellular, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porifera
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals. Etymology The term ''sponge'' derives from the Ancient Greek word ( 'sponge'). Overview Sponges are similar to other animals in that they are multicellular, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underwater Work
Underwater work is work done underwater, generally by divers during diving operations, but includes work done underwater by remotely operated vehicles and crewed submersibles. Skills commonly used by all professional diving occupations Underwater navigation *Pilotage involves navigation by naturally observable landmarks and phenomena, such as sunlight, water movement, bottom composition (for example, sand ripples run parallel to the direction of the wave front, which tends to run parallel to the shore), bottom contour and noise. Although natural navigation is taught on courses, developing the skills is generally more a matter of experience. *Compass navigation is a matter of training, practice and familiarity with the use of underwater compasses, combined with various techniques for reckoning distance underwater, including kick cycles (one complete upward and downward sweep of a kick), time, and occasionally by actual measurement, which may involve the length of umbilical deploye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sponge Diving
Sponge diving is underwater diving to collect soft natural sponges for human use. Background Most sponges are too rough for general use due to their structural spicules composed of calcium carbonate or silica. But two genera, ''Hippospongia'' and ''Spongia'', have soft, entirely fibrous skeletons. These two genera are most commonly used by humans. It is unknown when exactly the sponge became an article of use. In Ancient Greek writings, Homer and Plato mentioned the sponge as an object used for bathing. Through trading, Europeans used soft sponges for many purposes including padding for helmets, portable drinking utensils and municipal water filters. Until the invention of synthetic sponges, they were used as cleaning tools, applicators for paints and ceramic glazes, and discreet contraceptives. However, by the mid-20th century, over-fishing had brought both the animals and the industry close to extinction. Many objects with sponge-like textures are now made of substances not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skandalopetra
diving () dates from ancient Greece, when it was used by sponge fishermen, and has been re-discovered in recent years as a freediving discipline. It was in this discipline that the first world record in freediving was registered, when the Greek sponge fisherman Stathis Chantzis dived to a depth of 83 m (272 ft) in July 1913. It consists of a variable ballast dive using a tied to a rope. A companion on a boat recovers the diver by pulling the rope up after the descent, and keeps a watch on the diver from the surface. Origins A skandalopetra dive known to contemporary divers is that of Stathis Chantzis, a Greek sponge fisherman who, on 14 July 1913, in the Karpathos port recovered the lost anchor of the Regina Margherita, a ship of the Italian Navy, at the depth of 83 m. That feat is considered the first depth record in apnea diving. The , or simply (), is a stone, usually of marble or granite, weighing between 8 and 14 kg, with rounded corners and hydrodynamic shape. It w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the east by the Levant. The Sea has played a central role in the history of Western civilization. Geological evidence indicates that around 5.9 million years ago, the Mediterranean was cut off from the Atlantic and was partly or completely desiccated over a period of some 600,000 years during the Messinian salinity crisis before being refilled by the Zanclean flood about 5.3 million years ago. The Mediterranean Sea covers an area of about , representing 0.7% of the global ocean surface, but its connection to the Atlantic via the Strait of Gibraltar—the narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates the Iberian Peninsula in Europe from Morocco in Africa—is only wide. The Mediterranean S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sponge Fishing LCCN2003666909
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals. Etymology The term ''sponge'' derives from the Ancient Greek word ( 'sponge'). Overview Sponges are similar to other animals in that they are multicellular, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aegean Sea
The Aegean Sea ; tr, Ege Denizi (Greek: Αιγαίο Πέλαγος: "Egéo Pélagos", Turkish: "Ege Denizi" or "Adalar Denizi") is an elongated embayment of the Mediterranean Sea between Europe and Asia. It is located between the Balkans and Anatolia, and covers an area of some 215,000 square kilometres. In the north, the Aegean is connected to the Marmara Sea and the Black Sea by the straits of the Dardanelles and the Bosphorus. The Aegean Islands are located within the sea and some bound it on its southern periphery, including Crete and Rhodes. The sea reaches a maximum depth of 2,639m to the west of Karpathos. The Thracian Sea and the Sea of Crete are main subdivisions of the Aegean Sea. The Aegean Islands can be divided into several island groups, including the Dodecanese, the Cyclades, the Sporades, the Saronic islands and the North Aegean Islands, as well as Crete and its surrounding islands. The Dodecanese, located to the southeast, includes the islands of R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freediving
Freediving, free-diving, free diving, breath-hold diving, or skin diving is a form of underwater diving that relies on breath-holding until resurfacing rather than the use of breathing apparatus such as scuba gear. Besides the limits of breath-hold, immersion in water and exposure to high ambient pressure also have physiological effects that limit the depths and duration possible in freediving. Examples of freediving activities are traditional fishing techniques, competitive and non-competitive freediving, competitive and non-competitive spearfishing and freediving photography, synchronised swimming, underwater football, underwater rugby, underwater hockey, underwater target shooting and snorkeling. There are also a range of "competitive apnea" disciplines; in which competitors attempt to attain great depths, times, or distances on a single breath. Historically, the term ''free diving'' was also used to refer to scuba diving, due to the freedom of movement compared with sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boat Building
Boat building is the design and construction of boats and their systems. This includes at a minimum a hull, with propulsion, mechanical, navigation, safety and other systems as a craft requires. Construction materials and methods Wood Wood is the traditional boat building material used for hull and spar construction. It is buoyant, widely available and easily worked. It is a popular material for small boats (of e.g. length; such as dinghies and sailboats). Its abrasion resistance varies according to the hardness and density of the wood and it can deteriorate if fresh water or marine organisms are allowed to penetrate the wood. Woods such as Teak, Totara and some cedars have natural chemicals which prevent rot whereas other woods, such as Pinus radiata, will rot very quickly. The hull of a wooden boat usually consists of planking fastened to frames and a keel. Keel and frames are traditionally made of hardwoods such as oak while planking can be oak but is more often so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kalymnos
Kalymnos ( el, Κάλυμνος) is a Greek island and municipality in the southeastern Aegean Sea. It belongs to the Dodecanese island chain, between the islands of Kos (south, at a distance of ) and Leros (north, at a distance of less than ): the latter is linked to it through a series of islets. Kalymnos lies between two and five hours away by sea from Rhodes. In 2011 the island had a population of 16,001, making it the third most populous island of the Dodecanese, after Kos and Rhodes. It is known in Greece for the affluence of much of its population, and also stands as both the wealthiest member of the Dodecanese and one of the wealthiest Greek islands overall. The Municipality of Kalymnos, which includes the populated offshore islands of Pserimos (pop. 80), Telendos (94), Kalolimnos (2), and Pláti (2), as well as several uninhabited islets, has a combined land area of and a total population of 16,179 inhabitants. Naming The island is known as ''Càlino'' in Italian and ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
