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Blue Hole
A blue hole is a large marine cavern or sinkhole, which is open to the surface and has developed in a bank or island composed of a carbonate bedrock (limestone or coral reef). Blue holes typically contain tidally influenced water of fresh, marine, or mixed chemistry. They extend below sea level for most of their depth and may provide access to submerged cave passages. Well-known examples are the Blue Hole of Dahab in the Red Sea, Dragon Hole in the South China Sea and, in the Caribbean, the Great Blue Hole and Dean's Blue Hole. ''Blue holes'' are distinguished from ''cenotes'' in that the latter are inland voids usually containing fresh groundwater rather than seawater. Description Blue holes are roughly circular, steep-walled depressions, and so named for the dramatic contrast between the dark blue, deep waters of their depths and the lighter blue of the shallows around them. Their water circulation is poor, and they are commonly anoxic below a certain depth; this enviro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Blue Hole
The Great Blue Hole is a large Blue hole, marine sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll from the mainland and Belize City. The hole is circular in shape, across and deep. It has a surface area of . It was formed during several phases of the Quaternary glaciation when sea levels were much Last glacial period, lower. Analysis of stalactites found in the Great Blue Hole shows that formation took place 153,000, 66,000, 60,000, and 15,000 years ago. As the ocean began to rise again, the cave was flooded. The Great Blue Hole is a part of the larger Belize Barrier Reef, Belize Barrier Reef Reserve System, a UNESCO World Heritage Site. Exploration The site was made famous by Jacques Cousteau, who declared it one of the top five scuba diving sites in the world. In 1971 he brought his ship, the ''RV Calypso, Calypso'', to the hole to chart its depths. Investigations by this expedition confirmed the hole's origin as typical karst lim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seawater
Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately of dissolved salts (predominantly sodium () and chloride () ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at ) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about . The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was . Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measuremen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halocline
A halocline (or salinity chemocline), from the Greek words ''hals'' (salt) and ''klinein'' (to slope), refers to a layer within a body of water ( water column) where there is a sharp change in salinity (salt concentration) with depth. Haloclines are typically found in oceans or large estuaries and it is a type of chemical stratification that is most commonly found in places where freshwater from rivers or melting ice, mixes with salty ocean water. Description In the midlatitudes, an excess of evaporation over precipitation leads to surface waters being saltier than deep waters. In such regions, the vertical stratification is due to surface waters being warmer than deep waters and the halocline is destabilizing. Such regions may be prone to salt fingering, a process which results in the preferential mixing of salinity. In these regions, the halocline is important in allowing for the formation of sea ice, and limiting the escape of carbon dioxide to the atmosphere. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Weathering
Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs ''in situ'' (on-site, with little or no movement), and so is distinct from erosion, which involves the transport of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity. Weathering processes are either physical or chemical. The former involves the breakdown of rocks and soils through such mechanical effects as heat, water, ice and wind. The latter covers reactions to water, atmospheric gases and biologically produced chemicals with rocks and soils. Water is the principal agent behind both kinds, though atmospheric oxygen and carbon dioxide and the activities of biological organisms are also important. Biological chemical weathering is also called biological weathering. The materials left after the rock breaks down combine with organic material to create soi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Level
Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised geodetic datumthat is used, for example, as a chart datum in cartography and Navigation, marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to Calibration, calibrate altitude and, consequently, aircraft flight levels. A common and relatively straightforward mean sea-level standard is instead a long-term average of tide gauge readings at a particular reference location. The term ''above sea level'' generally refers to the height above mean sea level (AMSL). The term APSL means above present sea level, comparing sea levels in the past with the level today. Earth's radius at sea level is 6,378.137 km (3,963.191 mi) at the equator. It is 6,356.752 km (3,94 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary Glaciation
The Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial period, glacial and interglacial, interglacial periods during the Quaternary period that began 2.58 Year#SI prefix multipliers, Ma (million years ago) and is ongoing. Although geologists describe this entire period up to the present as an "ice age", in popular culture this term usually refers to the Last Glacial Period, most recent glacial period, or to the Pleistocene epoch in general. Since Earth still has polar Ice sheet, ice sheets, geologists consider the Quaternary glaciation to be ongoing, though currently in an interglacial period. During the Quaternary glaciation, ice sheets appeared, expanding during glacial periods and contracting during interglacial periods. Since the end of the last glacial period, only the Antarctic ice sheet, Antarctic and Greenland ice sheets have survived, while other sheets formed during glacial periods, such as the Laurentide Ice Sheet, hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bahamas
The Bahamas, officially the Commonwealth of The Bahamas, is an archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of its population. It comprises more than 3,000 islands, cays and islets in the Atlantic Ocean, and is located north of Cuba and north-west of the island of Hispaniola (split between the Dominican Republic and Haiti) and the Turks and Caicos Islands, southeast of the U.S. state of Florida and east of the Florida Keys. The capital and largest city is Nassau on the island of New Providence. The Royal Bahamas Defence Force describes the Bahamas' territory as encompassing of ocean space. The Bahama islands were inhabited by the Arawak and Lucayans, a branch of the Arawakan- speaking Taíno, for many centuries. Christopher Columbus was the first European to see the islands, making his first landfall in the "New World" in 1492 when he landed on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long Island, Bahamas
Long Island is an island in The Bahamas that is split by the Tropic of Cancer. It is one of the Districts of the Bahamas and is known as the most scenic island in the Bahamas. Its capital is Clarence Town. The population of Long Island is 3,094 inhabitants.LONG ISLAND POPULATION BY SETTLEMENT AND TOTAL NUMBER OF OCCUPIED DWELLINGS: 2010 CENSUS - Bahamas Department of Statistics Geography Long Island is about 130 kilometers (80 mi) long and wide at its widest point. The land area is . Long Island is situated about southeast of the juice capital of[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clarence Town
Clarence Town is a town in The Bahamas. It is located on Long Island. Clarence Town is the capital of Long Island and has a population of 86 people as of 2010.LONG ISLAND POPULATION BY SETTLEMENT AND TOTAL NUMBER OF OCCUPIED DWELLINGS: 2010 CENSUS - Bahamas Department of Statistics It has a marina, two restaurants as well as the government dock where the mail boat docks on a weekly basis. It also has a small grocery store, gas station and a small pub as well as a police station, post office and community centre. There are two churches in Clarence Town, both designed by |
Chetumal Bay
Chetumal Bay is a semi-closed mesohaline estuary on the southern coast of the Yucatán Peninsula. It is located in northern Belize and southeastern Mexico. Geography The mouth of Chetumal Bay is directed southward and buffered by the large Belizean island of Ambergris Caye. Corozal Bay is a smaller inland inlet, that extends to the southwest in the upper region of Chetumal Bay. It is named after the town of Corozal on it. Chetumal is a major city on the bay, located in the Mexican state of Quintana Roo. Blue holes Chetumal Bay contains several blue hole A blue hole is a large marine cavern or sinkhole, which is open to the surface and has developed in a bank or island composed of a carbonate bedrock (limestone or coral reef). Blue holes typically contain tidally influenced water of fresh, ma ...s, most notably the Taam Ja' Blue Hole. With a depth of at least , it is the world deepest known blue hole. See also * * References Bays of the Caribbean Bays of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taam Ja' Blue Hole
Taam Ja' blue hole is an underwater sinkhole located in Chetumal Bay at the southeast corner of the Yucatán Peninsula, Mexico. Its name means ''deep water'' in the Mayan language. While the bottom of the hole still has not been physically explored, the hole has been estimated to be over deep, making it the deepest known blue hole. Discovery It was discovered in about 2003 by a local diver, named Jesús Artemio Poot-Vill, who followed a grouper that went into its mouth. The hole was forgotten until the son of that fisherman began working with marine academic Juan Carlos Alcérreca-Huerta, who took soundings of its depth and was surprised by the results. The initial rediscovery came in 2016, when it was thought that the hole had a depth of 275 meters (902 feet), which still would have placed it as the second deepest blue hole, in comparisons to the Dragon Hole, at 300.89 metres (987 ft), and Dean's Blue Hole, at 202 metres (663 ft). In 2021, Poot-Vill came into contact wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. Calcium carbonate is the second most common type of sand. One such example of this is aragonite, which has been created over the past 500million years by various forms of life, such as coral and shellfish. It is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years, as in the Caribbean. Somewhat more rarely, sand may be composed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
