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70-607: It is also a popular spot among domestic tourists due to its white sand beaches and coral reefs that attract many marine life enthusiasts. Khor Fakkan beach lies to the north of the center of the town. Khor Fakkan is located on the east coast of the UAE, between the Shumayliyah Mountains and the Arabian Sea, with an altitude of 1,023 meters (3,356 ft) at al Hilqah Mountain (Jebel al Hilqah). The bay of Khor Fakkan faces

140-749: A Darwin Point is reached. One such point exists at the northwestern end of the Hawaiian Archipelago; see Evolution of Hawaiian volcanoes#Coral atoll stage . However, reefs in the Persian Gulf have adapted to temperatures of 13 °C (55 °F) in winter and 38 °C (100 °F) in summer. 37 species of scleractinian corals inhabit such an environment around Larak Island . Deep-water coral inhabits greater depths and colder temperatures at much higher latitudes, as far north as Norway. Although deep water corals can form reefs, little

210-644: A continental shelf, and not around a volcanic island, Darwin's principles apply. Development stopped at the barrier reef stage, since Australia is not about to submerge. It formed the world's largest barrier reef, 300–1,000 m (980–3,280 ft) from shore, stretching for 2,000 km (1,200 mi). Healthy tropical coral reefs grow horizontally from 1 to 3 cm (0.39 to 1.18 in) per year, and grow vertically anywhere from 1 to 25 cm (0.39 to 9.84 in) per year; however, they grow only at depths shallower than 150 m (490 ft) because of their need for sunlight, and cannot grow above sea level. As

280-586: A list of places on the east coast of the United Arab Emirates , which is considered by historians to indicate Khor Fakkan. The Portuguese built a fort at Khor Fakkan that was a ruin by 1666. The log book of the Dutch vessel the Meerkat mentions this fort and another one, describing "Gorfacan" as a place on a small bay, with about 200 small houses built from date branches, near the beach. It refers to

350-514: A long history of human settlement. There is evidence of post holes from the wooden uprights of the traditional barasti huts known as areesh , similar to those found at Tell Abraq which dates from the 3rd to 1st millennium BC. Excavations by a team from the Sharjah Archaeological Museum have identified 34 graves and a settlement belonging to the early-mid 2nd millennium BC . These are clustered on rock outcrops overlooking

420-412: A pinhead to 12 inches (30 cm) across. Reef-building or hermatypic corals live only in the photic zone (above 70 m), the depth to which sufficient sunlight penetrates the water. Coral polyps do not photosynthesize, but have a symbiotic relationship with microscopic algae ( dinoflagellates ) of the genus Symbiodinium , commonly referred to as zooxanthellae . These organisms live within

490-496: A pseudo-atoll. These can be distinguished from real atolls only by detailed investigation, possibly including core drilling. Some platform reefs of the Laccadives are U-shaped, due to wind and water flow. Atolls or atoll reefs are a more or less circular or continuous barrier reef that extends all the way around a lagoon without a central island. They are usually formed from fringing reefs around volcanic islands. Over time,

560-433: A rapidly subsiding bottom can overwhelm coral growth, killing the coral and the reef, due to what is called coral drowning . Corals that rely on zooxanthellae can die when the water becomes too deep for their symbionts to adequately photosynthesize , due to decreased light exposure. The two main variables determining the geomorphology , or shape, of coral reefs are the nature of the substrate on which they rest, and

630-455: A ship are set so that two standard 20-foot containers have a gap of three inches, allowing a single 40-foot container to fit precisely on top. The 40-foot containers have found wider acceptance, as they can be pulled by semi-trailer trucks . The length of such a combination is within the limits of national road regulations in many countries, requiring no special permission. As some road regulations allow longer trucks, there are also variations of

700-420: A triangular Portuguese fortress on the northern side, in ruins, and a fortress on a hill on the southern side, also in ruins, without garrison or artillery. As well as date palms, the Meerkat ' s log also mentions fig trees, melons, watermelons and myrrh . It notes several wells with "good and fresh water" used for irrigation. One reason suggested for the ruinous state of the forts is an invasion in 1623 of

770-448: A volume range of 680 to 1,520 cubic feet (19 to 43 m ) for one TEU. While the TEU is not itself a measure of mass, some conclusions can be drawn about the maximum mass that a TEU can represent. The maximum gross mass for a 20-foot (6.1 m) dry cargo container is 24,000 kilograms (53,000 lb). Subtracting the tare mass of the container itself, the maximum amount of cargo per TEU

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840-423: A zone extending from approximately 30° N to 30° S of the equator. Tropical corals do not grow at depths of over 50 meters (160 ft). The optimum temperature for most coral reefs is 26–27 °C (79–81 °F), and few reefs exist in waters below 18 °C (64 °F). When the net production by reef building corals no longer keeps pace with relative sea level and the reef structure permanently drowns

910-468: Is a general unit of cargo capacity, often used for container ships and container ports . It is based on the volume of a 20-foot-long (6.1 m) intermodal container , a standard-sized metal box that can be easily transferred between different modes of transportation, such as ships, trains, and trucks. The standard intermodal container is 19 feet 10.5 inches (6.058 m) long and eight feet (2.44 m) wide. The height of such containers

980-454: Is an underwater ecosystem characterized by reef-building corals . Reefs are formed of colonies of coral polyps held together by calcium carbonate . Most coral reefs are built from stony corals , whose polyps cluster in groups. Coral belongs to the class Anthozoa in the animal phylum Cnidaria , which includes sea anemones and jellyfish . Unlike sea anemones, corals secrete hard carbonate exoskeletons that support and protect

1050-578: Is constantly changing. Each reef is made up of irregular patches of algae, sessile invertebrates, and bare rock and sand. The size, shape and relative abundance of these patches change from year to year in response to the various factors that favor one type of patch over another. Growing coral, for example, produces constant change in the fine structure of reefs. On a larger scale, tropical storms may knock out large sections of reef and cause boulders on sandy areas to move. Coral reefs are estimated to cover 284,300 km (109,800 sq mi), just under 0.1% of

1120-547: Is defined as two TEU. It is common to designate a 45-foot (13.7 m) container as 2 TEU, rather than 2.25 TEU. The most common twenty-foot container occupies a space 20 feet (6.1 m) long, 8 feet (2.44 m) wide, and 8 feet 6 inches (2.59 m) high, with an allowance externally for the corner castings ; the internal volume is 1,172 cubic feet (33.2 m ). However, both 9-foot-6-inch-tall (2.90 m) High cube and 4-foot-3-inch (1.30 m) half height containers are also reckoned as 1 TEU. This gives

1190-445: Is directly attached to a shore, or borders it with an intervening narrow, shallow channel or lagoon. It is the most common reef type. Fringing reefs follow coastlines and can extend for many kilometres. They are usually less than 100 metres wide, but some are hundreds of metres wide. Fringing reefs are initially formed on the shore at the low water level and expand seawards as they grow in size. The final width depends on where

1260-523: Is known about them. The northernmost coral reef on Earth is located near Eilat , Israel . Coral reefs are rare along the west coasts of the Americas and Africa , due primarily to upwelling and strong cold coastal currents that reduce water temperatures in these areas (the Humboldt , Benguela , and Canary Currents , respectively). Corals are seldom found along the coastline of South Asia —from

1330-460: Is most commonly 8 feet 6 inches (2.59 m) but ranges from 4 feet 3 inches (1.30 m) to 9 feet 6 inches (2.90 m). Another standard container is slightly more than twice as long: 40-foot (12.19 m), dubbed a forty-foot equivalent unit (often FEU or feu ). The reason the smaller container is 1.5 inches short of 20 feet is to allow it to be stacked efficiently with 40-foot containers. The twistlocks on

1400-418: Is often the reef's most diverse area. Coral and calcareous algae provide complex habitats and areas that offer protection, such as cracks and crevices. Invertebrates and epiphytic algae provide much of the food for other organisms. A common feature on this forereef zone is spur and groove formations that serve to transport sediment downslope. The reef flat is the sandy-bottomed flat, which can be behind

1470-820: Is part of the Maritime Silk Road that runs from the Chinese coast to the south via the southern tip of India to Mombasa , from there through the Red Sea via the Suez Canal to the Mediterranean, there to the Upper Adriatic region to the northern Italian hub of Trieste with its rail connections to Central Europe , Eastern Europe and the North Sea . Khor Fakkan lies on the east coast of

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1540-465: Is reduced to about 21,600 kilograms (47,600 lb). Similarly, the maximum gross mass for a 40-foot (12.2 m) dry cargo container (including the 9-foot-6-inch (2.90 m) High cube container) is 30,480 kilograms (67,200 lb). After correcting for tare weight, this gives a cargo capacity of 26,500 kilograms (58,400 lb). Twenty-foot "heavy tested" containers are available for heavy goods such as heavy machinery. These containers allow

1610-539: Is sunny and warm during the day; the evenings are cool and humidity low. Daytime temperatures range from 18 to 30 °C (64 to 86 °F). One may expect rain and tropical storms between January and March. The climate warms from May to September with the high temperature at noon in July and August reaching 40 °C (104 °F). The nights too are warm, with the temperature reaching 36 °C (97 °F), with high humidity. Khor Fakkan has one 4 star holiday beach resort,

1680-418: Is usually measured by mass (the deadweight tonnage ) or by volume (the net register tonnage ). Deadweight tonnage is generally measured now in metric tons ( tonnes ). Register tons are measured in cu. ft, with one register ton equivalent to 100 cubic feet (2.83 m ). As the TEU is an inexact unit, it cannot be converted precisely into other units. The related unit forty-foot equivalent unit , however,

1750-475: The Late Cretaceous (100–66 Ma), when reefs formed by a group of bivalves called rudists existed; one of the valves formed the main conical structure and the other, much smaller valve acted as a cap. Measurements of the oxygen isotopic composition of the aragonitic skeleton of coral reefs, such as Porites , can indicate changes in sea surface temperature and sea surface salinity conditions during

1820-739: The Mesoamerican Barrier Reef System and the New Caledonian Barrier Reef . Barrier reefs are also found on the coasts of Providencia , Mayotte , the Gambier Islands , on the southeast coast of Kalimantan , on parts of the coast of Sulawesi , southeastern New Guinea and the south coast of the Louisiade Archipelago . Platform reefs, variously called bank or table reefs, can form on the continental shelf , as well as in

1890-592: The Middle Cambrian (513–501 Ma ), Devonian (416–359 Ma) and Carboniferous (359–299 Ma), owing to extinct order Rugosa corals, and Late Cretaceous (100–66 Ma) and Neogene (23 Ma–present), owing to order Scleractinia corals. Not all reefs in the past were formed by corals: those in the Early Cambrian (542–513 Ma) resulted from calcareous algae and archaeocyathids (small animals with conical shape, probably related to sponges ) and in

1960-609: The Persian navy under the control of Omani Sheikh Muhammad Suhari. Suhari, facing a Portuguese counterattack, withdrew to the Portuguese forts, including that of Khorfakkan. When the Persians were expelled, the Portuguese commander Rui Freire urged the people of Khorfakkan to remain loyal to the Portuguese crown and established a Portuguese customs office as well. In 1737, long after the Portuguese had been expelled from Arabia,

2030-417: The tropics where the water is agitated, but can only live within a limited depth range, starting just below low tide . Where the level of the underlying earth allows, the corals grow around the coast to form fringing reefs, and can eventually grow to become a barrier reef. Where the bottom is rising, fringing reefs can grow around the coast, but coral raised above sea level dies. If the land subsides slowly,

2100-738: The Indian Ocean, for example, in the Maldives , the Chagos Islands , the Seychelles and around Cocos Island . The entire Maldives consist of 26 atolls. Coral reef ecosystems contain distinct zones that host different kinds of habitats. Usually, three major zones are recognized: the fore reef, reef crest, and the back reef (frequently referred to as the reef lagoon). The three zones are physically and ecologically interconnected. Reef life and oceanic processes create opportunities for

2170-1236: The Oceanic Hotel. The fish, fruit and vegetable souq is located at the southern end of the corniche and near the main highway. Shees Park , a recreational park is located near the village of Shis . The highest building in the city is the Al Suhub Rest House , which overlooks Khor Fakkan from a height of 580 metres above sea level. 25°20′N 56°21′E  /  25.333°N 56.350°E  / 25.333; 56.350 15th century 16th century 15th century 16th century 17th century 18th century 19th century 16th century 17th century 15th century 16th century Portuguese India 17th century Portuguese India 18th century Portuguese India 16th century 17th century 19th century Portuguese Macau 20th century Portuguese Macau 15th century [Atlantic islands] 16th century [Canada] 16th century 17th century 18th century 19th century Coral reef A coral reef

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2240-507: The Persian Gulf and includes Khor Fakkan. At the turn of the 19th century, Lorimer notes that Khor Fakkan had about 5,000 date trees and was home to about 150 houses of Naqbiyin and Arabicised Persians, amounting to some 800 people. The population lived by cultivation and pearling, and the town had seven shops. The German submarine U-533 sank about 25 miles (40 km) off the coast on 16 October 1943 during World War II. Divers found

2310-747: The Persians again invaded Khor Fakkan, with some 5,000 men and 1,580 horses, with the help of the Dutch , during their intervention in the Omani civil war. In 1765 Khor Fakkan belonged to a sheikh of the Al Qasimi , Sharjah 's ruling family, according to the German traveler Carsten Niebuhr . There is a map by the French cartographer Rigobert Bonne dating to about 1770 that shows the Arabian Peninsula and

2380-469: The UAE, between the Indian Ocean and the Shumayliyyah or Western Hajar Mountains . The bay of Khor Fakkan is north-east facing and is protected from prevailing winds by a jetty serving the container terminal. Tourism is well developed thanks to sandy beaches and the coral reefs that attract many divers. Khor Fakkan Beach lies to the north of the center of the town. From November to April Khor Fakkan

2450-599: The UV radiation and allowing them to better adapt to warmer water temperatures. In the event of UV or thermal damage, if and when repair occurs, it will increase the likelihood of survival of the host and symbiont. This leads to the idea that, evolutionarily, clade A is more UV resistant and thermally resistant than the other clades. Clades B and C are found more frequently in deeper water, which may explain their higher vulnerability to increased temperatures. Terrestrial plants that receive less sunlight because they are found in

2520-1188: The area of France, yet they provide a home for at least 25% of all marine species , including fish , mollusks , worms , crustaceans , echinoderms , sponges , tunicates and other cnidarians . Coral reefs flourish in ocean waters that provide few nutrients. They are most commonly found at shallow depths in tropical waters, but deep water and cold water coral reefs exist on smaller scales in other areas. Shallow tropical coral reefs have declined by 50% since 1950, partly because they are sensitive to water conditions. They are under threat from excess nutrients (nitrogen and phosphorus), rising ocean heat content and acidification , overfishing (e.g., from blast fishing , cyanide fishing , spearfishing on scuba ), sunscreen use, and harmful land-use practices, including runoff and seeps (e.g., from injection wells and cesspools). Coral reefs deliver ecosystem services for tourism, fisheries and shoreline protection . The annual global economic value of coral reefs has been estimated at anywhere from US$ 30–375 billion (1997 and 2003 estimates) to US$ 2.7 trillion (a 2020 estimate) to US$ 9.9 trillion (a 2014 estimate). Though

2590-502: The coast. The fringing reefs of the Red Sea are "some of the best developed in the world" and occur along all its shores except off sandy bays. Barrier reefs are separated from a mainland or island shore by a deep channel or lagoon . They resemble the later stages of a fringing reef with its lagoon but differ from the latter mainly in size and origin. Their lagoons can be several kilometres wide and 30 to 70 metres deep. Above all,

2660-485: The coastal plains had become continental islands . As sea level rise continued, water topped most of the continental islands. The corals could then overgrow the hills, forming cays and reefs. Sea level on the Great Barrier Reef has not changed significantly in the last 6,000 years. The age of living reef structure is estimated to be between 6,000 and 8,000 years. Although the Great Barrier Reef formed along

2730-451: The coral animals. Coral that loses a large fraction of its zooxanthellae becomes white (or sometimes pastel shades in corals that are pigmented with their own proteins) and is said to be bleached , a condition which, unless corrected, can kill the coral. There are eight clades of Symbiodinium phylotypes . Most research has been conducted on clades A–D. Each clade contributes their own benefits as well as less compatible attributes to

2800-533: The coral. Most reefs grow best in warm, shallow, clear, sunny and agitated water. Coral reefs first appeared 485 million years ago, at the dawn of the Early Ordovician , displacing the microbial and sponge reefs of the Cambrian . Sometimes called rainforests of the sea , shallow coral reefs form some of Earth's most diverse ecosystems. They occupy less than 0.1% of the world's ocean area, about half

2870-415: The corals shelter the zooxanthellae, averaging one million for every cubic centimetre of coral, and provide a constant supply of the carbon dioxide they need for photosynthesis. The varying pigments in different species of zooxanthellae give them an overall brown or golden-brown appearance and give brown corals their colors. Other pigments such as reds, blues, greens, etc. come from colored proteins made by

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2940-471: The dawn of the 16th century, it and its port were defended by a wide walled belt facing the land, closing the gorge that, in the mountain range parallel to the coast, allows communication with the interior. In this monumental structure a single door was torn, defended by a tower. The ensemble was responsible for safeguarding eventual tribal attacks. In 1580 the Venetian jeweler Gasparo Balbi noted "Chorf" in

3010-529: The deep sea away from continental shelves , around oceanic islands and atolls . The majority of these islands are volcanic in origin. Others have tectonic origins where plate movements lifted the deep ocean floor. In The Structure and Distribution of Coral Reefs , Charles Darwin set out his theory of the formation of atoll reefs, an idea he conceived during the voyage of the Beagle . He theorized that uplift and subsidence of Earth's crust under

3080-637: The eastern tip of India ( Chennai ) to the Bangladesh and Myanmar borders —as well as along the coasts of northeastern South America and Bangladesh, due to the freshwater release from the Amazon and Ganges Rivers respectively. Significant coral reefs include: When alive, corals are colonies of small animals embedded in calcium carbonate shells. Coral heads consist of accumulations of individual animals called polyps , arranged in diverse shapes. Polyps are usually tiny, but they can range in size from

3150-479: The exchange of seawater , sediments , nutrients and marine life. Most coral reefs exist in waters less than 50 m deep. Some inhabit tropical continental shelves where cool, nutrient-rich upwelling does not occur, such as the Great Barrier Reef . Others are found in the deep ocean surrounding islands or as atolls, such as in the Maldives . The reefs surrounding islands form when islands subside into

3220-401: The floor often supports seagrass meadows which are important foraging areas for reef fish. The reef drop-off is, for its first 50 m, habitat for reef fish who find shelter on the cliff face and plankton in the water nearby. The drop-off zone applies mainly to the reefs surrounding oceanic islands and atolls. The reef face is the zone above the reef floor or the reef drop-off. This zone

3290-403: The fringing reef, barrier reef, atoll and table reef based on Stoddart, D.R. (1969). Spalding et al. list four main reef types that can be clearly illustrated – the fringing reef, barrier reef, atoll, and "bank or platform reef"—and notes that many other structures exist which do not conform easily to strict definitions, including the "patch reef". A fringing reef, also called a shore reef,

3360-463: The fringing reefs keep pace by growing upwards on a base of older, dead coral, forming a barrier reef enclosing a lagoon between the reef and the land. A barrier reef can encircle an island, and once the island sinks below sea level a roughly circular atoll of growing coral continues to keep up with the sea level, forming a central lagoon. Barrier reefs and atolls do not usually form complete circles but are broken in places by storms. Like sea level rise ,

3430-419: The growth of the coral. This technique is often used by climate scientists to infer a region's paleoclimate . Since Darwin's identification of the three classical reef formations – the fringing reef around a volcanic island becoming a barrier reef and then an atoll – scientists have identified further reef types. While some sources find only three, Thomas lists "Four major forms of large-scale coral reefs" –

3500-501: The harbor. Around 1500, Duarte Barbosa described it as a village “around which are gardens and farms in plenty”. The town was captured by the Portuguese Empire in the 16th century by naval commander General Afonso de Albuquerque and was referred to as Corfacão. It was part of a serial of fortified cities that the Portuguese used to control access to the Persian Gulf and Gulf of Oman, including Muscat, Sohar and Hormuz. At

3570-548: The history of the change in sea level relative to that substrate. The approximately 20,000-year-old Great Barrier Reef offers an example of how coral reefs formed on continental shelves. Sea level was then 120 m (390 ft) lower than in the 21st century. As sea level rose, the water and the corals encroached on what had been hills of the Australian coastal plain. By 13,000 years ago, sea level had risen to 60 m (200 ft) lower than at present, and many hills of

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3640-666: The island erodes away and sinks below sea level. Atolls may also be formed by the sinking of the seabed or rising of the sea level. A ring of reefs results, which enclose a lagoon. Atolls are numerous in the South Pacific, where they usually occur in mid-ocean, for example, in the Caroline Islands , the Cook Islands , French Polynesia , the Marshall Islands and Micronesia . Atolls are found in

3710-418: The main reef, containing chunks of coral. This zone may border a lagoon and serve as a protective area, or it may lie between the reef and the shore, and in this case is a flat, rocky area. Fish tend to prefer it when it is present. The reef lagoon is an entirely enclosed region, which creates an area less affected by wave action and often contains small reef patches. However, the topography of coral reefs

3780-484: The mainland. Unlike fringing and barrier reefs which extend only seaward, platform reefs grow in all directions. They are variable in size, ranging from a few hundred metres to many kilometres across. Their usual shape is oval to elongated. Parts of these reefs can reach the surface and form sandbanks and small islands around which may form fringing reefs. A lagoon may form In the middle of a platform reef. Platform reefs are typically situated within atolls, where they adopt

3850-400: The name "patch reefs" and often span a diameter of just a few dozen meters. In instances where platform reefs develop along elongated structures, such as old and weathered barrier reefs, they tend to arrange themselves in a linear formation. This is the case, for example, on the east coast of the Red Sea near Jeddah . In old platform reefs, the inner part can be so heavily eroded that it forms

3920-528: The name implies, coral reefs are made up of coral skeletons from mostly intact coral colonies. As other chemical elements present in corals become incorporated into the calcium carbonate deposits, aragonite is formed. However, shell fragments and the remains of coralline algae such as the green-segmented genus Halimeda can add to the reef's ability to withstand damage from storms and other threats. Such mixtures are visible in structures such as Eniwetok Atoll . The times of maximum reef development were in

3990-550: The northeast and is protected from prevailing winds by a jetty serving terminal for container ships. In the mountains of Khor Fakkan and off the Sharjah-Khor Fakkan highway lies the Rifaisa Dam that is considered to have been built over a village, and thus when the water is very quiet, the tops of the old houses are visible. The development of Al Rifaisa Dam spans an area of 10,684 square meters. Khor Fakkan has

4060-415: The ocean, and atolls form when an island subsides below the surface of the sea. Alternatively, Moyle and Cech distinguish six zones, though most reefs possess only some of the zones. The reef surface is the shallowest part of the reef. It is subject to surge and tides . When waves pass over shallow areas, they shoal , as shown in the adjacent diagram. This means the water is often agitated. These are

4130-528: The oceans formed the atolls. Darwin set out a sequence of three stages in atoll formation. A fringing reef forms around an extinct volcanic island as the island and ocean floor subside. As the subsidence continues, the fringing reef becomes a barrier reef and ultimately an atoll reef. Darwin predicted that underneath each lagoon would be a bedrock base, the remains of the original volcano. Subsequent research supported this hypothesis. Darwin's theory followed from his understanding that coral polyps thrive in

4200-535: The oceans' surface area. The Indo-Pacific region (including the Red Sea , Indian Ocean , Southeast Asia and the Pacific ) account for 91.9% of this total. Southeast Asia accounts for 32.3% of that figure, while the Pacific including Australia accounts for 40.8%. Atlantic and Caribbean coral reefs account for 7.6%. Although corals exist both in temperate and tropical waters, shallow-water reefs form only in

4270-490: The offshore outer reef edge formed in open water rather than next to a shoreline. Like an atoll, it is thought that these reefs are formed either as the seabed lowered or sea level rose. Formation takes considerably longer than for a fringing reef, thus barrier reefs are much rarer. The best known and largest example of a barrier reef is the Australian Great Barrier Reef . Other major examples are

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4340-451: The open ocean, in fact anywhere where the seabed rises close enough to the surface of the ocean to enable the growth of zooxanthemic, reef-forming corals. Platform reefs are found in the southern Great Barrier Reef, the Swain and Capricorn Group on the continental shelf, about 100–200 km from the coast. Some platform reefs of the northern Mascarenes are several thousand kilometres from

4410-429: The polyps' tissues and provide organic nutrients that nourish the polyp in the form of glucose , glycerol and amino acids . Because of this relationship, coral reefs grow much faster in clear water, which admits more sunlight. Without their symbionts, coral growth would be too slow to form significant reef structures. Corals get up to 90% of their nutrients from their symbionts. In return, as an example of mutualism ,

4480-420: The precise condition under which corals flourish. The light is sufficient for photosynthesis by the symbiotic zooxanthellae, and agitated water brings plankton to feed the coral. The off-reef floor is the shallow sea floor surrounding a reef. This zone occurs next to reefs on continental shelves. Reefs around tropical islands and atolls drop abruptly to great depths and do not have such a floor. Usually sandy,

4550-412: The sea bed begins to drop steeply. The surface of the fringe reef generally remains at the same height: just below the waterline. In older fringing reefs, whose outer regions pushed far out into the sea, the inner part is deepened by erosion and eventually forms a lagoon . Fringing reef lagoons can become over 100 metres wide and several metres deep. Like the fringing reef itself, they run parallel to

4620-609: The shallow water tropical coral reefs are best known, there are also deeper water reef-forming corals, which live in colder water and in temperate seas. Most coral reefs were formed after the Last Glacial Period when melting ice caused sea level to rise and flood continental shelves . Most coral reefs are less than 10,000 years old. As communities established themselves, the reefs grew upwards, pacing rising sea levels . Reefs that rose too slowly could become drowned, without sufficient light. Coral reefs are also found in

4690-519: The standard 40-foot container; in Europe and most other places a container of 45 feet (13.72 m) may be pulled as a trailer. Containers with a length of 48 feet (14.63 m) or 53 feet (16.15 m) are restricted to road and rail transport in North America. Although longer than 40 feet, these variants are put in the same class of forty-foot equivalent units. The carrying capacity of a ship

4760-424: The survival of their coral hosts. Each photosynthetic organism has a specific level of sensitivity to photodamage to compounds needed for survival, such as proteins. Rates of regeneration and replication determine the organism's ability to survive. Phylotype A is found more in the shallow waters. It is able to produce mycosporine-like amino acids that are UV resistant , using a derivative of glycerin to absorb

4830-429: The undergrowth are analogous to clades B, C, and D. Since clades B through D are found at deeper depths, they require an elevated light absorption rate to be able to synthesize as much energy. With elevated absorption rates at UV wavelengths, these phylotypes are more prone to coral bleaching versus the shallow clade A. Twenty-foot equivalent unit The twenty-foot equivalent unit (abbreviated TEU or teu )

4900-644: The wreck at a depth of 108 metres (354 ft) in 2009. The modern Khor Fakkan Container Terminal was inaugurated in 1979, and is the only natural deep-sea port in the region, and one of the top ports in the Emirates for containers. The Dh 300 million ($ 81.75 million) project involved reclaiming some 150,000 square metres (1,600,000 sq ft) to increase the storage capacity and to facilitate large cranes, and 16 metres (52 ft) deep quays to accommodate for major vessels over 400 metres (1,300 ft) in length. As of 2004 it handled 1.6 million TEU 's. The port

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