18 résultats pour "reefs"

• Coral Reef.

  sensitive to particles of mud or sediment settling on them, which means that corals rarely grow close to rivers or other sources of sediment. In the sea, light is filteredout by depth, so reef-building corals can only grow in relatively shallow water. Even in the clearest oceans few reef-building corals grow below a depth of 80 to 100 m(260 to 328 ft). Although corals need nutrients, they cannot thrive in areas where there are large amounts of nutrients. Typically, microscopic organisms in the p...

• Coral Reefs - geography.

• Barrière (Grande) ou Reef.

• Coral - biology.

  Soft corals lack a distinct skeleton. Although they live in colonies, the individual polyps are fused into a complex body, usually strengthened by small lumps or spikesknown as sclerites, which are made of protein and calcite. Soft corals come in a variety of shapes, including undulating sheets, upright mushroomlike shapes, andbeautiful shapes that form branches. A number of other octocorals have skeletons made from a hard or horny protein, sometimes strengthened with more brittle calcareous dep...

• Animal - biology.

  Vertebrates are customarily divided into cold-blooded and warm-blooded animals, but these labels are not very precise. Biologists normally use the terms ectoderm and endoderm to describe temperature regulation more accurately. An ectoderm is an animal whose temperature is dictated by its surroundings, while an endoderm is one that keeps its body at a constant warm temperature by generating internal heat. Reptiles, amphibians, and fish are ectoderms. Although they do not maintain a constant wa...

• Coral great barrier reef

  Coral is essential for life on earth. At the same time, it is one of the planet’s most threatened ecosystems, directly impacted by global ocean warming from anthropogenic climate change. The Great Barrier Reef, one of UNESCO’s World Heritage Sites known for its ‘enormous scientific and intrinsic importance’, has just undergone its third mass bleaching event in five years, affecting 25% of the entire reef. How do we save this marvel before it’s too late? We can all agree that the reef with...

• Hawaii (state) - geography.

  limestone along the coast. The volcanoes of the Hawaiian Islands are all so-called shield volcanoes, or lava domes. Unlike the volcanoes of Alaska and South America, those of Hawaii were notcreated by very explosive eruptions. Formed mostly by lava flows, they are great rounded mountain masses, rather than steep-sided cones. Mauna Kea, dormant forcenturies, is the highest mountain in the state. It rises to 4,205 m (13,796 ft) above sea level, and its summit is dotted with cinder cones formed by...

• Hawaii (state) - USA History.

  limestone along the coast. The volcanoes of the Hawaiian Islands are all so-called shield volcanoes, or lava domes. Unlike the volcanoes of Alaska and South America, those of Hawaii were notcreated by very explosive eruptions. Formed mostly by lava flows, they are great rounded mountain masses, rather than steep-sided cones. Mauna Kea, dormant forcenturies, is the highest mountain in the state. It rises to 4,205 m (13,796 ft) above sea level, and its summit is dotted with cinder cones formed by...

• Africa.

  The highest elevations in Africa are found in the various ranges of East Africa. After Kilimanjaro, the next highest peaks are Mount Kenya (5,199 m/17,057 ft), north ofKilimanjaro in central Kenya; Margherita Peak (5,109 m/ 16,762 ft) in the Ruwenzori Range on the border between Uganda and the Democratic Republic of the Congo(DRC); Ras Dashen (4,620 m/ 15,157 ft) in the Ethiopian Highlands of northern Ethiopia; Mount Meru (4,565 m/ 14,977 ft), close to Kilimanjaro in Tanzania; and MountElgon (4,...

• Africa - Geography.

  The highest elevations in Africa are found in the various ranges of East Africa. After Kilimanjaro, the next highest peaks are Mount Kenya (5,199 m/17,057 ft), north ofKilimanjaro in central Kenya; Margherita Peak (5,109 m/ 16,762 ft) in the Ruwenzori Range on the border between Uganda and the Democratic Republic of the Congo(DRC); Ras Dashen (4,620 m/ 15,157 ft) in the Ethiopian Highlands of northern Ethiopia; Mount Meru (4,565 m/ 14,977 ft), close to Kilimanjaro in Tanzania; and MountElgon (4,...

• Belize - country.

  Education is compulsory for children between the ages of 5 and 14. Attendance at primary schools was nearly universal in 2002–2003, but only 78 percent of children ofsecondary school age were enrolled in school. Higher education is available at colleges in Belize City and Corozal. The literacy rate of 93 percent is one of the highest inLatin America. C Government Belize is governed under a constitution that became effective at independence in 1981. Belize recognizes the British monarch as its o...

• Republic of Indonesia - country.

  Mahakam in East Kalimantan and the Martapura and Barito in South Kalimantan. Most of these rivers originate in the island’s central massif (mountain mass) and meander through extensive swamps as they approach the coast. Settlements such as Samarinda and Banjarmasin cluster along the rivers, which serve ascommunication routes into the interior. The largest rivers on Sumatra drain from west to east into the Strait of Malacca. In the north, the Asahan River once linked trade between the Batak peo...

• Antigua and Barbuda - country.

  The monetary unit of Antigua and Barbuda is the East Caribbean (EC) dollar of 100 cents (2.70 East Caribbean dollars equal U.S.$1, a fixed rate since 1976). VI ENVIRONMENTAL CONCERNS The growth of the tourist industry has created some environmental problems, including uncontrolled disposal of sewage from hotels on the beach. Hotel developmentalso threatens the Antiguan mangrove trees. Water management is another major area of concern because of limited natural freshwater resources. Coral reefs...

• Sailing.

  the sails sweep across the decks of the vessel from one side to the other, and also because of the danger of breaking spars. In wild jibing, control can be lostmomentarily and, if the seas are high, a small boat can broach —that is, veer on its side with danger of swamping or capsizing. An unintentional jibe in a heavy wind frequently has enough force to break the masts of a vessel. When jibing intentionally, careful sailors always haul in on the boom while turning, so that the boom willtravel...

• Diving (underwater).

  compensator (or control) device (BCD or BC), which the diver wears as a vest. By adding air to the BCD, the diver becomes more buoyant and rises. By releasing air,the diver becomes less buoyant and sinks. With minor adjustments of air, the diver can achieve neutral buoyancy. A third hose attaches to pressure gauges that diversuse to monitor how much air remains in the tank. A fourth hose attaches to a backup breathing device called an alternate air source, or octopus. Divers also wear a belt w...

• Africa - history.

  Africa’s other major mountainous regions occur at the northern and southern fringes of the continent. The Atlas Mountains, a system of high ranges, extend for 2,200 km(1,400 mi) across Morocco, Algeria, and Tunisia, roughly parallel to the northern coast. These ranges enclose a number of broad inland basins and plateaus. In the west, theHigh (or Grand) Atlas contains Toubkal (4,165 m/ 13,665 ft), the highest peak of the system. Toward the east, the Atlas consists of two parallel ranges: the Tell...

• Africa.

  The highest elevations in Africa are found in the various ranges of East Africa. After Kilimanjaro, the next highest peaks are Mount Kenya (5,199 m/17,057 ft), north ofKilimanjaro in central Kenya; Margherita Peak (5,109 m/ 16,762 ft) in the Ruwenzori Range on the border between Uganda and the Democratic Republic of the Congo(DRC); Ras Dashen (4,620 m/ 15,157 ft) in the Ethiopian Highlands of northern Ethiopia; Mount Meru (4,565 m/ 14,977 ft), close to Kilimanjaro in Tanzania; and MountElgon (4,...

• Thailand - country.

  E Natural Resources Thailand possesses a range of mineral resources. Tin is mined in the peninsula. Important gemstones, such as sapphires, are found in the southeast, and coal reserves,particularly lignite, are in the north. Fish are abundant in rivers and coastal waters. In addition to being consumed domestically, fish are also exported. F Climate Thailand experiences a typical monsoon climate. Winds blow from the northeast during the winter months of October to March or April (known as the...