Some of the biodiversity of a coral reef, in this case the Great Barrier Reef, Australia. Biodiversity is the variation of Life forms within a given Ecosystem, Biome or for the entire Earth. The Great Barrier Reef is the largest Coral reef system in the world composed of over 2900 individual reefs and 900 islands stretching for 2600 kilometres (1600 mi

Coral reefs are aragonite structures produced by living organisms, found in shallow, tropical marine waters with little to no nutrients in the water. Aragonite is a Carbonate mineral, one of the two common naturally occurring polymorphs of Calcium carbonate, Ca[[carbon C]] O 3 High nutrient levels such as those found in runoff from agricultural areas can harm the reef by encouraging the growth of algae. Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms ^[1] In most reefs, the predominant organisms are stony corals, colonial cnidarians that secrete an exoskeleton of calcium carbonate. Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 The accumulation of skeletal material, broken and piled up by wave action and bioeroders, produces a massive calcareous formation that supports the living corals and a great variety of other animal and plant life. Bioerosion describes the Erosion of hard ocean substrates by living organisms by a number of mechanisms Although corals are found both in temperate and tropical waters, reefs are formed only in a zone extending at most from 30°N to 30°S of the equator. Reef-forming corals do not grow at depths of over 30 m (100 ft), and temperature has less of an effect on distribution but it is generally accepted that no corals exist in waters below 18 °C. ^[2]

Corals reefs in Papua New Guinea. Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many Papua New Guinea (or ˈpæpjuːə in Tok Pisin: Papua Niugini) officially the Independent State of Papua New Guinea, is a country in Oceania

Corals reefs with feather star fish in Papua New Guinea. Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many Crinoids, also known as sea lilies or feather-stars, are marine animals that make up the class Crinoidea of the Echinoderms (phylum Echinodermata Papua New Guinea (or ˈpæpjuːə in Tok Pisin: Papua Niugini) officially the Independent State of Papua New Guinea, is a country in Oceania

Biology

Anatomy of a coral polyp.

See also: Coral

The building blocks of coral reefs are the generation of reef-building , and other organisms that are composed of calcium carbonate. Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 For example, as a coral head grows, it lays down a skeletal structure encasing each new polyp. In Zoology, a polyp is one of two forms of individuals found in many species of Cnidarians The two are the polyp or hydroid and the medusa. Waves, grazing fish (such as parrotfish), sea urchins, sponges, and other forces and organisms break down the coral skeletons into fragments that settle into spaces in the reef structure. Parrotfish are mostly tropical Perciform marine Fish of the family Scaridae. Sea urchins are small globular spiny sea cat animals composing most of class Echinoidea. The sponges or poriferans (from Latin porus "pore" and ferre "to bear" are Animals Many other organisms living in the reef community contribute their skeletal calcium carbonate in the same manner. Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 Coralline algae are important contributors to the structure of the reef in those parts of the reef subjected to the greatest forces by waves (such as the reef front facing the open ocean). Coralline algae are Red algae in the Family Corallinaceae of the order Corallinales. These algae contribute to reef-building by depositing limestone in sheets over the surface of the reef and thereby contributing also to the structural integrity of the reef.

Reef-building or hermatypic corals are only found in the photic zone (above 50 m depth), the depth to which sufficient sunlight penetrates the water for photosynthesis to occur. The photic zone or euphotic zone ( Greek 'well lit' is the depth of the water in a Lake or Ocean, that is exposed to sufficient Sunlight Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. The coral polyps do not photosynthesize, but have a symbiotic relationship with single-celled algae called zooxanthellae; these algal cells within the tissues of the coral polyps carry out photosynthesis and produce excess organic nutrients that are then used by the coral polyps. This article is about the biological phenomenon for other uses see Symbiosis (disambiguation The term symbiosis (from the Greek Zooxanthellae (plural ˌzoʊoʊzænˈθɛli are golden-brown intracellular Endosymbionts of various marine Animals and Protozoa, especially Anthozoans Because of this relationship, coral reefs grow much faster in clear water, which admits more sunlight. Indeed, the relationship is responsible for coral reefs in the sense that without their symbionts, coral growth would be too slow for the corals to form impressive reef structures. Corals can get up to 90% of their nutrients from their zooxanthellae symbionts. ^[3]

Corals can reproduce both sexually and asexually. An individual polyp may use both reproductive modes within its lifetime. Corals reproduce sexually by either internal or external fertilization. The reproductive cells are found on the mesentery membranes that radiate inward from the layer of tissue that lines the stomach cavity. Some mature adult corals are hermaphroditic; others are exclusively male or female. A few even change sex as they grow.

Internally fertilized eggs are brooded in the polyp for a period ranging from days to weeks. Subsequent development produces a tiny larva, known as a planula. Externally fertilized eggs develop during a synchronized spawning. Polyps release eggs and sperm into the water simultaneously. This spawning method disperses eggs over a larger area. Synchronous spawning depends on four factors: time of year, water temperature, and tidal and lunar cycles. Spawning is most successful when there is little variation between high and low tides. The less water movement there is over the reef, the better the chance that an egg will be fertilized. Ideal timing occurs in the spring, release of eggs or planula larvae usually occurs at night and is sometimes in phase with the lunar cycle (3-6 days after a full moon). The period from release to settlement lasts only a few days, but some planulae can survive afloat for several weeks (7, 14). They are vulnerable at this time to heavy predation and adverse environmental conditions. For the lucky few which survive to attach to substrate, the challenge comes from competition for food and space.

Formations

Coral reefs can take a variety of forms, defined in following:

• Fringing reef – a reef that is directly attached to a shore or borders it with an intervening shallow channel or lagoon. A Fringing reef is a kind of Coral reef, that is located in the Tropics generally immediately near the shoreline
• Barrier reef – a reef separated from a mainland or island shore by a deep lagoon (see Great Barrier Reef). A lagoon is a body of comparatively shallow salt or Brackish water separated from the deeper Sea by a shallow or exposed sandbank, coral The Great Barrier Reef is the largest Coral reef system in the world composed of over 2900 individual reefs and 900 islands stretching for 2600 kilometres (1600 mi
• Patch reef – an isolated, often circular reef, usually within a lagoon or embayment. A lagoon is a body of comparatively shallow salt or Brackish water separated from the deeper Sea by a shallow or exposed sandbank, coral Headlands and bays are two related features of the coastal environment
• Apron reef – a short reef resembling a fringing reef, but more sloped; extending out and downward from a point or peninsular shore.
• Bank reef – a linear or semi-circular in outline, larger than a patch reef.
• Ribbon reef – a long, narrow, somewhat winding reef, usually associated with an atoll lagoon.
• Atoll reef – a more or less circular or continuous barrier reef extending all the way around a lagoon without a central island; see atoll. An atoll (pronounced /ˈætʌl/ is an island of Coral that encircles a Lagoon partially or completely
• Table reef – an isolated reef, approaching an atoll type, but without a lagoon.

Distribution

Locations of coral reefs.

Coral reefs are estimated to cover 284,300 square kilometres, with the Indo-Pacific region (including the Red Sea, Indian Ocean, Southeast Asia and the Pacific) accounting for 91. The Indo-Pacific is a biogeographic region of the earth's seas comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean The Red Sea is a Salt water Inlet of the Indian Ocean between Africa and Asia. The Indian Ocean is the third largest of the world's Oceanic divisions covering about 20% of the water on the Earth 's surface The Pacific Ocean is the largest of the Earth 's Oceanic divisions 9% of the total. Southeast Asia accounts for 32. 3% of that figure, while the Pacific including Australia accounts for 40. For a topic outline on this subject see List of basic Australia topics. 8%. Atlantic and Caribbean coral reefs only account for 7. The Caribbean (ˌkærəˡbiən kæ'rəbiən Cariben|Caraïben or Caraïben; Caraïbe or more commonly Antilles; Caribe is a Region consisting 6% of the world total. ^[4]

Coral reefs are either restricted or absent from the west coast of the Americas, as well as the west coast of Africa. The Americas are the lands of the Western hemisphere or New World, consisting of the Continents of North America and South America This is due primarily to upwelling and strong cold coastal currents that reduce water temperatures in these areas. Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense cooler and usually nutrient-rich water towards the ocean surface replacing the warmer ^[5] Corals are also restricted from off the coastline of South Asia from Pakistan to Bangladesh. Pakistan () officially the Islamic Republic of Pakistan, is a country located in South Asia, Southwest Asia, Middle East and ( Bengali: বাংলাদেশ inc-Latn Bangladesh) officially ^[4] They are also restricted along the coast around north-eastern South America and Bangladesh due to the release of vast quantities of freshwater from the Amazon and Ganges Rivers respectively. South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a ( Bengali: বাংলাদেশ inc-Latn Bangladesh) officially The Amazon River (Rio Amazonas Río Amazonas of South America is the largest river in the world by volume with a total river flow greater than the next top ten largest rivers The Ganges (ˈgænʤiːz also Ganga, Devanāgarī: hi गंगा in most Indian languages) is the major river in the Indian subcontinent

Famous coral reefs and reef areas of the world include:

• The Great Barrier Reef - largest coral reef system in the world, Queensland, Australia;
• The Belize Barrier Reef - second largest in the world, stretching from southern Quintana Roo, Mexico and all along the coast of Belize down to the Bay Islands of Honduras. The Great Barrier Reef is the largest Coral reef system in the world composed of over 2900 individual reefs and 900 islands stretching for 2600 kilometres (1600 mi Queensland is a state of Australia, occupying the north-eastern corner of the mainland continent The Belize Barrier Reef is a series of Coral reefs straddling the coast of Belize, roughly 300 m (0
• The New Caledonia Barrier Reef - second longest double barrier reef in the world, with a length of about 1500km. The New Caledonia Barrier Reef is located in New Caledonia in the South Pacific, and is the second-longest Coral reef in the world after Australia
• The Andros, Bahamas Barrier Reef - third largest in the world, following along the east coast of Andros Island, Bahamas between Andros and Nassau. Andros Island is the largest Island of the Bahamas and the fifth largest island in the West Indies at roughly 2300 square miles (6000 km² in area and 104 miles
• The Red Sea Coral Reef - located off the coast of Egypt and Saudi Arabia. The Red Sea is a Salt water Inlet of the Indian Ocean between Africa and Asia.
• Pulley Ridge - deepest photosynthetic coral reef, Florida
• Many of the numerous reefs found scattered over the Maldives

Ecology and biodiversity

A school of Pennant coralfish, Pyramid and Millet butterflyfishes, and others at the Rapture Reef, French Frigate Shoals

Coral reefs support an extraordinary biodiversity; although they are located in nutrient-poor tropical waters. Pulley Ridge is a coral Reef off the coast of southwestern Florida, United States. Florida ( is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the The Maldives ( or, or Maldive Islands) officially the Republic of Maldives, is an Island nation consisting of a group of atolls stretching The pennant coralfish or Coachman, Heniochus acuminatus, is a Tropical fish of the family Chaetodontidae. The Pyramid Butterflyfish ( Hemitaurichthys polylepis) is a species of Butterflyfish in the genus Hemitaurichthys. The Millet Butterflyfish, Chaetodon miliaris, is a Species of Butterflyfish ( family Chaetodontidae The French Frigate Shoals ( Hawaiian: Kānemilohai) is the largest Atoll in the Northwestern Hawaiian Islands. Biodiversity is the variation of Life forms within a given Ecosystem, Biome or for the entire Earth. The process of nutrient cycling between corals, zooxanthellae, and other reef organisms provides an explanation for why coral reefs flourish in these waters: recycling ensures that fewer nutrients are needed overall to support the community. In Ecology and Earth science, a biogeochemical cycle is a circuit or pathway by which a Chemical element or Molecule moves through both biotic

Cyanobacteria also provide soluble nitrates for the coral reef through the process of nitrogen fixation. Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy In Inorganic chemistry, a nitrate is a salt of Nitric acid with an Ion composed of one Nitrogen and three Oxygen atoms Nitrogen fixation is the process by which Nitrogen is taken from its natural relatively inert molecular form (N2 in the atmosphere and converted into Corals absorb nutrients, including inorganic nitrogen and phosphorus, directly from the water, and they feed upon zooplankton that are carried past the polyps by water motion. Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Zooplankton are the Heterotrophic (sometimes detritivorous) type of Plankton. ^[6] Thus, primary productivity on a coral reef is very high, which results in the highest values per square meter, at 5-10g C m^-2 day^-1. See also Primary production (economics Primary production is the production of Organic compounds from atmospheric or aquatic Carbon dioxide, ^[7] Producers in coral reef communities include the symbiotic zooxanthellae, coralline algae, and various seaweeds, especially small types called turf algae, although scientists disagree about the importance of these particular organisms. Seaweed is a loose colloquial term encompassing macroscopic Multicellular, benthic marine Algae. ^[6]

Coral reefs are home to a variety of tropical or reef fish, such as the colorful parrotfish, angelfish, damselfish and butterflyfish. Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Parrotfish are mostly tropical Perciform marine Fish of the family Scaridae. Marine angelfish are Perciform Fish of the family Pomacanthidae. Damselfish refers to members of the family Pomacentridae, except those of the two genera Amphiprion and Premnas The Freshwater butterflyfish are in family Pantodontidae. The butterflyfish are a group of conspicuous tropical marine Fish Other fish groups found on coral reefs include groupers, snappers, grunts and wrasses. For other meanings see Grouper (disambiguation. Groupers are Fish of any of a number of genera in the subfamily Epinephelinae of The grunts are a family Haemulidae, of fishes in the order Perciformes. The wrasses are a family, Labridae, of marine Fish, many of which are brightly colored Over 4,000 species of fish inhabit coral reefs. ^[4] It has been suggested that the high number of fish species that inhabit coral reefs are able to coexist in such high numbers because any free living space is rapidly inhabited by the first planktonic fish larvae that occupy it. These fish then inhabit the space for the rest of their life. The species that inhabit the free space is random and has therefore been termed 'a lottery for living space'. ^[8]

Reefs are also home to a large variety of other organisms, including sponges, Cnidarians (which includes some types of corals and jellyfish), worms, crustaceans (including shrimp, spiny lobsters and crabs), molluscs (including cephalopods), echinoderms (including starfish, sea urchins and sea cucumbers), sea squirts, sea turtles and sea snakes. The sponges or poriferans (from Latin porus "pore" and ferre "to bear" are Animals Cnidaria (naɪˈdɛəriə is a phylum containing some 9000 Species of Animals found exclusively in aquatic mostly marine, environments Jellyfish are free-swimming members of the phylum Cnidaria. They have several different basic morphologies that represent several different cnidarian classes including the A worm is a common name given to a diverse group of invertebrate animals that have a long soft body and no legs Structure of crustaceans As Arthropods crustaceans have a stiff Exoskeleton, which must be shed to allow the animal to grow ( Ecdysis or molting True shrimp are swimming decapod Crustaceans classified in the Infraorder Caridea, found widely around the world in both fresh This article is about the animal For the B-52's song see Rock Lobster. Crabs are decapod Crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (βραχύ / brachy Molluscs are animals belonging to the phylum Mollusca. There are around 250000 extant Species within the phylum with an estimated 70000 The cephalopods ( Greek plural (kephalópoda "head-feet" are the Mollusc class Cephalopoda characterized by Echinoderms (Phylum Echinodermata) are a phylum of marine Animals (including Sea stars) Starfish (also called sea stars) are any Echinoderms belonging to the class Asteroidea. The sea cucumber (also known as trepang, bêche-de-mer, or ambiguously Sea slug) is an Echinoderm of the class Holothuroidea Tunicate, also known as urochordata, tunicata (and by the common names of urochordates, sea squirts, and sea pork) is the Sea turtles ( Superfamily Chelonioidea) are Turtles found in all the world's oceans except the Arctic Ocean. For sea snakes in mythology and cryptozoology see Sea serpent. Aside from humans, mammals are rare on coral reefs, with visiting cetaceans such as dolphins being the main group. Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands The Order Cetacea (sɪˈteɪʃiə L cetus, whale includes Whales Dolphins and Porpoises Cetus is Dolphins are Marine mammals that are closely related to Whales and Porpoises There are almost forty species of dolphin in seventeen genera. A few of these varied species feed directly on corals, while others graze on algae on the reef and participate in complex food webs. Food chains, also called food networks and/or trophic networks, describe the feeding relationships between species within an Ecosystem. ^[6][4]

A number of invertebrates, collectively called cryptofauna, inhabit the coral skeletal substrate itself, either boring into the skeletons (through the process of bioerosion) or living in pre-existing voids and crevices. Bioerosion describes the Erosion of hard ocean substrates by living organisms by a number of mechanisms Those animals boring into the rock include sponges, bivalve molluscs, and sipunculans. The Sipuncula or Sipunculida, sipunculid worms or peanut worms, are a phylum containing 144-320 Species (estimates vary of bilaterally Those settling on the reef include many other species, particularly crustaceans and polychaete worms. The Polychaeta or polychaetes are a class of Annelid worms generally marine ^[5]

Due to their vast biodiversity, many governments world-wide take measures to protect their coral reefs. In Australia, the Great Barrier Reef is protected by the Great Barrier Reef Marine Park Authority, and is the subject of much legislation, including a Biodiversity Action Plan. The Great Barrier Reef Marine Park protects a large part of Australia 's Great Barrier Reef from damaging activities This article is about a conservation biology topic For other uses of BAP see BAP (disambiguation.

Algae and coral reef

Researchers found evidence of algae dominance in locations of healthy coral reefs. In surveys done around largely uninhabited US Pacific islands, algae consists of a large percentage of the surveyed coral locations. ^[9] The algae population consists of turf algae, coralline algae, and macroalgae. Coralline algae are Red algae in the Family Corallinaceae of the order Corallinales. Seaweed is a loose colloquial term encompassing macroscopic Multicellular, benthic marine Algae.

Threats

Bioerosion (coral damage) such as this may be caused by coral bleaching. Coral bleaching is the loss of color of Corals due to stress-induced expulsion of symbiotic Unicellular Algae or due to the loss of pigmentation within ^[10]

Human activity may represent the greatest threat to coral reefs living in Earth's oceans. An ocean (from Greek, ''Okeanos'' (Oceanus) is a major body of saline water, and a principal component of the Hydrosphere. In particular, pollution and over-fishing are the most serious threats to these ecosystems. Pollution is the introduction of contaminants into an environment that causes instability disorder harm or discomfort to the physical systems or living organisms they are in Physical destruction of reefs due to boat and shipping traffic is also a problem. The live food fish trade has been implicated as a driver of decline due to the use of cyanide and disaster for peoples living in the tropics. The live food fish trade is a global system that links Fishing communities with markets primarily in Hong Kong and mainland China. A cyanide is any Chemical compound that contains the cyano group (C≡N which consists of a Carbon Atom triple-bonded to a Hughes, et al, (2003), writes that "with increased human population and improved storage and transport systems, the scale of human impacts on reefs has grown exponentially. The world population is the total number of living Humans on Earth at a given time For example, markets for fishes and other natural resources have become global, supplying demand for reef resources far removed from their tropical sources. Natural resources are naturally occurring substances that are considered valuable in their relatively unmodified ( natural) form "^[11]

Currently researchers are working to determine the degree various factors impact the reef systems. The list of factors is long but includes the oceans acting as a carbon dioxide sink, changes in Earth's atmosphere, ultraviolet light, ocean acidification, biological virus, impacts of dust storms carrying agents to far flung reef systems, various pollutants, impacts of algal blooms and others. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable An algal bloom is a rapid increase in the population of Algae in an aquatic system Reefs are threatened well beyond coastal areas and so the problem is broader than factors from land development and pollution though those are too causing considerable damage.

Land development and pollution

Extensive and poorly managed land development can threaten the survival of coral reefs. Within the last 20 years, once prolific mangrove forests, which absorb massive amounts of nutrients and sediment from runoff caused by farming and construction of roads, buildings, ports, channels, and harbors, are being destroyed. Mangroves (generally are Trees and Shrubs that grow in saline coastal habitats in the Tropics and Subtropics. Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of Nutrient-rich water causes fleshy algae and phytoplankton to thrive in coastal areas in suffocating amounts known as algal blooms. An algal bloom is a rapid increase in the population of Algae in an aquatic system Coral reefs are biological assemblages adapted to waters with low nutrient content, and the addition of nutrients favors species that disrupt the balance of the reef communities. Both the loss of wetlands and mangrove habitats are considered to be significant factors affecting water quality on inshore reefs. Water quality is the physical chemical and biological characteristics of Water in relationship to a set of standards ^[12]

Poor water quality has also been shown to encourage the spread of infectious diseases among corals. An infectious disease is a clinically evident Disease resulting from the presence of Pathogenic microbial agents including Pathogenic viruses Pathogenic ^[13]

Copper, a common industrial pollutant, has been shown to interfere with the life history and development of coral polyps. Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 The term life history has been given many meanings in several scientific fields ^[14] Fish Trade The hobby of keeping saltwater aquaria has experienced an increase in world popularity since the 1990s. Beyond sales of aquaria, air pumps, food, medications and other supplies, the primary product of the aquarium industry is fish. However, the world market is limited in the diversity of collected species. For example, among 4000 coral reef fish species, only 200–300 are exploited. Selection of species results from a demand for fish being highly colorful and being able to be maintained and fed in aquaria. The last point is very important in the choice of imported species.

Although a few fish species (e. g. Pomacentridae) can be reproduced in aquaria, 95% of exploited fish are directly collected in the coral environment. Intense sampling of coral reef fish, especially in South-East Asia (including Indonesia and the Philippines), has caused great damage to the environment. A major catalyst of cyanide fishing is poverty within fishing communities. Cyanide fishing is an illegal form of Fishing (commonly known as Poaching) common in South East Asia, which usually uses the Chemical compound In areas like the Philippines where cyanide is regularly used to catch live aquarium fish, the percentage of the population below the poverty line is 40%. ^[15] In such developing countries, a fisherman might resort to such unethical practices in order to prevent his or her family from starving. Developing countries are countries that haven't reached Western-style standards of democratic government free market economy industrialization social programs and human rights guaranties

Most, 80–90%, of aquarium fish exported from the Philippines are captured with sodium cyanide. Sodium cyanide is the Inorganic compound with the formula NaCN This toxic chemical is dissolved in sea water and released into fish shelters. It has a rapid narcotic effect on fish, which are then easily captured. However, most fish collected with cyanide die a few months after capture from extensive liver damage. Moreover, other fish species that are not interesting for the aquarium market also die in the field. ^[16]

Dynamite fishing

Dynamite fishing is another extremely destructive method that fishermen use to harvest small fish. Blast fishing or dynamite fishing is the practice of using explosives to stun or kill schools of fish for easy collection Sticks of dynamite, grenades, or home-made explosives are lit or activated and thrown in the water. Once the dynamite goes off the explosion brings about an underwater shockwave, causing the internal organs of fish to liquefy, killing them almost instantly. A second blast is often set off after the first to kill any larger predators that are attracted to the initial kill of the smaller fish. This method of fishing not only kills the fish within the main blast area, but also takes the lives of many reef animals that are not edible or wanted. Also, many of the fish do not float to the surface to be collected, but sink to the bottom. The blast also kills the corals in the area, eliminating the very structure of the reef, destroying the habitat for fish and other animals important for the maintenance of a healthy reef. Areas that used to be full of coral become deserts, full of coral rubble, dead fish and little else after dynamite fishing. With dynamite fishing especially around the Maldives in the Indian Ocean, have caused a vast majority of problems. With the rising sea level already the coral reefs act as a natural defence against flooding. With the dynamite fishing, the coral reefs are destroyed making the islands more vulnerable to flooding.

Bleaching

Main article: Coral bleaching

During the 1998 and 2004 El Niño weather phenomena, in which sea surface temperatures rose well above normal, many tropical coral reefs were bleached or killed. Coral bleaching is the loss of color of Corals due to stress-induced expulsion of symbiotic Unicellular Algae or due to the loss of pigmentation within El Niño-Southern Oscillation ( ENSO; commonly referred to as simply El Niño) is a global coupled ocean-atmosphere phenomenon Sea surface temperature (SST is the water Temperature close to the surface Coral bleaching is the loss of color of Corals due to stress-induced expulsion of symbiotic Unicellular Algae or due to the loss of pigmentation within Some recovery has been noted in more remote locations, but global warming could negate some of this recovery in the future. Global warming is the increase in the average measured temperature of the High seas surface temperature (SSTs) coupled with high irradiance (light intensity), triggers the loss of zooxanthellae, a symbiotic algae, and its dinoflagellate pigmentation in corals causing coral bleaching. Zooxanthellae provide 95% of the energy to the coral host. Refer to Hoegh-Guldberg 1999 for more information.

Ocean acidification

Main article: Ocean acidification

The decreasing ocean surface pH is of increasing long-term concern for coral reefs. ^[17] Increased atmospheric CO₂ increases the amount of CO₂ dissolved in the oceans. ^[18] Carbon dioxide gas dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Carbonic acid (ancient name acid of air or aerial acid) has the formula H2CO3 Ocean surface pH is estimated to have decreased from approximately 8. 25 to 8. 14 since the beginning of the industrial era,^[19] and it is estimated that it will drop by a further 0. 3 - 0. 4 units by 2100 as the ocean absorbs more anthropogenic CO₂. ^[20] Under normal conditions, the conditions for calcium carbonate production are stable in surface waters since the carbonate ion is at supersaturating concentrations. The term supersaturation refers to a Solution that contains more of the dissolved material than could be dissolved by the Solvent under normal circumstances However, as ocean pH falls, so does the concentration of this ion, and when carbonate becomes under-saturated, structures made of calcium carbonate are vulnerable to dissolution. Research has already found that corals experience reduced calcification or enhanced dissolution when exposed to elevated CO₂. ^[21]

African and Asian dust outbreaks

Dust from the Sahara moving around the southern periphery of the subtropical ridge moves into the Caribbean and Florida during the warm season as the ridge builds and moves northward through the subtropical Atlantic. The Sahara (الصحراء الكبرى aṣ-ṣaḥrā´ al-kubra, "The Great Desert" is the world's largest hot Desert and the world's second largest The subtropical ridge is a large belt of high pressure situated around 30°N in the Northern Hemisphere and 30°S in the Southern Hemisphere. The Caribbean (ˌkærəˡbiən kæ'rəbiən Cariben|Caraïben or Caraïben; Caraïbe or more commonly Antilles; Caribe is a Region consisting Florida ( is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the Dust can also be attributed to a global transport from the Gobi and Taklamakan deserts across Korea, Japan, and the Northern Pacific to the Hawaiian Islands. The Gobi (Говь Govi or Gov', "gravel-covered plain" Chinese: zh-t 戈壁(沙漠 Gēbì (Shāmò) The Taklamakan Desert (Takelamagan Shamo 塔克拉玛干沙漠 also known as Taklimakan, is a Desert in Central Asia, in the Xinjiang Korea is a geographic area composed of two sovereign countries a civilization and a former state situated on the Korean Peninsula in East Asia. For a topic outline on this subject see List of basic Japan topics. The Pacific Ocean is the largest of the Earth 's Oceanic divisions The Hawaiian Islands, once known as the Sandwich Islands, form an Archipelago of 19 Islands and Atolls numerous smaller ^[22] Since 1970, dust outbreaks have worsened due to periods of drought in Africa. There is a large variability in the dust transport to the Caribbean and Florida from year to year;^[23] however, the flux of dust is greater during positive phases of the North Atlantic Oscillation. The North Atlantic oscillation (NAO is a climatic phenomenon in the North Atlantic Ocean of fluctuations in the difference of Sea-level pressure between ^[24] Dust events have been linked to a decline in the health of coral reefs across the Caribbean and Florida, primarily since the 1970s. ^[25] Studies have shown that corals can incorporate dust into their skeletons as identified from dust from the 1883 eruption of Krakatoa in Indonesia in the annular bands of the reef-building coral Montastraea annularis from the Florida reef tract. Krakatoa ( Indonesian: Krakatau) also spelled Krakatao or Krakatowa, is a volcanic island in the Sunda Strait The Republic of Indonesia ( (Republik Indonesia is a Country in Southeast Asia. Montastraea annularis, commonly known as the boulder star coral is a species of Coral that lives in the western Atlantic Ocean and is the Florida ( is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the ^[26] The relative abundance of chemical elements, particularly metals, has been used to distinguish soil derived from volcanic dust from mineral dust. Mineral dust is a term used to indicate atmospheric aerosols originated from thesuspension of Minerals constituting the Soil, being composed of various ^[27]

Destruction worldwide

Coral reefs and fishes in Papua New Guinea

Southeast Asian coral reefs are at risk from damaging fishing practices (such as cyanide and blast fishing), overfishing, sedimentation, pollution and bleaching. Papua New Guinea (or ˈpæpjuːə in Tok Pisin: Papua Niugini) officially the Independent State of Papua New Guinea, is a country in Oceania Southeast Asian coral reefs have the highest: levels of Biodiversity for the world's marine ecosystems For the computer security term see Phishing. Fishing is the activity of catching Fish. Cyanide fishing is an illegal form of Fishing (commonly known as Poaching) common in South East Asia, which usually uses the Chemical compound Blast fishing or dynamite fishing is the practice of using explosives to stun or kill schools of fish for easy collection Overfishing occurs when Fishing activities reduce fish stocks below an acceptable level A variety of activities, including education, regulation, and the establishment of marine protected areas are under way to protect these reefs. Indonesia, for example has nearly 33,000 square miles (85,000 km²) of coral reefs. The Republic of Indonesia ( (Republik Indonesia is a Country in Southeast Asia. Its waters are home to a third of the world’s total corals and a quarter of its fish species. Indonesia's coral reefs are located in the heart of the Coral Triangle and have been victim to destructive fishing, unregulated tourism, and bleaching due to climatic changes. Data from 414 reef monitoring stations throughout Indonesia in 2000 found that only 6% of Indonesia’s coral reefs are in excellent condition, while 24% are in good condition, and approximately 70% are in poor to fair condition (2003 The Johns Hopkins University).

On September 24, 2007, Reef Check (the world’s largest reef conservation organization) stated that only 5% of Philippines 27,000 square-kilometers of coral reef are in “excellent condition” : Tubbataha Reef, Marine Park in Palawan, Apo Island in Negros Oriental, Apo Reef in Puerto Galera, Mindoro, and Verde Island Passage off Batangas. Events 622 - Prophet Muhammad completes his hegira from Mecca to Medina. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Reef Check is an international Non-governmental organization dedicated to the conservation of two reef Ecosystems: tropical Coral reefs and Californian To conserve habitat life for wild species and prevent their Extinction or reduction in range is a priority of a great many groups that cannot be easily characterized in terms An organization (or organisation &mdash see spelling differences) is a social arrangement which pursues collective goals which controls its own performance and The Philippines ( Filipino: Pilipinas, officially known as the Republic of the Philippines (fil ''Republika ng Pilipinas'' RP The kilometre ( American spelling: kilometer) symbol km is a unit of Length in the Metric system, equal to one thousand Tubbataha Reef is an Atoll Coral reef located in the Sulu Sea of the Philippines. See also Marine reserve as many areas called parks are wholly or partly marine conservation reserves A marine park is a Park consisting Palawan is an Island province of the Philippines located in the MIMAROPA region. Negros Oriental (also called Oriental Negros) is a province of the Philippines located in the Central Visayas region. Puerto Galera is a 3rd class municipality in the province of Oriental Mindoro, Philippines. For the unincorporated community of Mindoro Wisconsin in the United States of America see Mindoro Wisconsin. Verde Island sits in the Verde Island Passage near Puerto Galera, Mindoro and Batangas, Luzon in The Philippines. This article is about the province For the city see Batangas City. Philippine coral reefs is 2nd largest in Asia. The Philippines ( Filipino: Pilipinas, officially known as the Republic of the Philippines (fil ''Republika ng Pilipinas'' RP Coral reefs are Aragonite structures produced by living organisms found in marine waters with little to no nutrients in the water ^[28]

General estimates show approximately 10% of the coral reefs around the world are already dead. ^[29][30]Problems range from environmental effects of fishing techniques, described above, to ocean acidification. The environmental effects of fishing can be divided into issues that involve the availability of fish to be caught such as Overfishing, Sustainable fisheries, and ^[31] Coral bleaching is another manifestation of the problem and is showing up in reefs across the planet. Coral bleaching is the loss of color of Corals due to stress-induced expulsion of symbiotic Unicellular Algae or due to the loss of pigmentation within

Protection and restoration

Aerial photo of Ahus Island, Papua New Guinea

Inhabitants of Ahus Island, Manus Province, Papua New Guinea, have followed a generations-old practice of restricting fishing in six areas of their reef lagoon. Papua New Guinea (or ˈpæpjuːə in Tok Pisin: Papua Niugini) officially the Independent State of Papua New Guinea, is a country in Oceania Manus Province is the smallest province in Papua New Guinea with a land area of 2100 km² but with more than 220000 km² of water Papua New Guinea (or ˈpæpjuːə in Tok Pisin: Papua Niugini) officially the Independent State of Papua New Guinea, is a country in Oceania While line fishing is permitted, net and spear fishing are restricted based on cultural traditions. The result is that both the biomass and individual fish sizes are significantly larger in these areas than in places where fishing is completely unrestricted. Biomass refers to living and recently dead Biological material that can be used as fuel or for industrial production ^[32][33]

It is estimated that about 60% of the world’s reefs are at risk due to destructive, human-related activities. The threat to the health of reefs is particularly strong in Southeast Asia, where an enormous 80% of reefs are considered endangered. An endangered species is a population of an organism which is at risk of becoming Extinct because it is either few in numbers or threatened by changing environmental or predation

Organisations as Coral Cay, Counterpart ^[34] and the Foundation of the peoples of the South Pacific are currently undertaking coral reef/atoll restoration projects. They are doing so using simple methods of plant propagation. Plant propagation is the process of artificially or naturally propagating (distributing or spreading Plants Sexual propagation (seed See also Other organisations as Practical Action have released informational documents on how to set-up coral reef restoration to the public. Practical Action is a development charity registered in the United Kingdom which works directly in four regions of the developing world – Latin America ^[35]

Marine Protected Areas

One method of coastal reef management that has become increasingly prominent is the implementation of Marine Protected Areas (MPAs). Marine Protected Area (MPA is often used as an umbrella term covering a wide range of marine areas with some level of restriction to protect living non-living cultural and/or historic MPAs have been introduced in Southeast Asia and elsewhere around the world to attempt to promote responsible fishery management and habitat protection. Fisheries management is today often referred to as a governmental system of management rules based on defined objectives and a mix of management means to implement the rules which is put A habitat (which is Latin for "it inhabits" is an Ecological or environmental area that is inhabited by a particular Species. Much like the designation of national parks and wild life refuges, potentially damaging extraction activities are prohibited. A national park is a reserve of land usually declared and owned by a national Government, protected from most Human development and pollution The objectives of MPAs are both social and biological, including restoration of coral reefs, aesthetic maintenance, increased and protected biodiversity, and economic benefits. Conflicts surrounding MPAs involve lack of participation, clashing views and perceptions of effectiveness, and funding.

Reef Restoration Technology

Low voltage electrical currents applied through seawater crystallizes dissolved minerals onto steel structures. The resultant white carbonate (aragonite) is the same mineral that makes up natural coral reefs. Aragonite is a Carbonate mineral, one of the two common naturally occurring polymorphs of Calcium carbonate, Ca[[carbon C]] O 3 Corals rapidly colonize and grow at faster than normal rates onto these coated structures. The change in the environment produced by electrical currents also accelerates formation and growth of both chemical limestone rock and the skeletons of corals and other shell-bearing organisms. Within the vicinity of the anode and cathode is a high pH environment which inhibits the growth of filamentous and fleshy algae, which compete with coral for space. This, and the increased growth rates cease when the mineral accretion process stops. ^[36]

The effects of mineral accretion is, however, only temporary. During the process the settled corals have an increased growth rate, and size, and density, but after the process is complete the corallites are comparable to naturally growing corallites in growth rate and density, and are about the same size or slightly smaller. ^[37]

Reefs in the past

Throughout the Earth history, from a few million years after hard skeletons were developed by marine organisms, there were almost always reefs formed by reef-building organisms in the ancient seas. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 The times of maximum development were in the Middle Cambrian (513-501 Ma), Devonian (416-359 My) and Carboniferous (359-299 Ma), due to Order Rugosa extinct corals, and Late Cretaceous (100-65 Ma) and all Neogene (23 Ma - present), due to Order Scleractinia corals. The Middle Cambrian (also known as Albertan, Acadian, St David's, or Saint David's) is the second of three geological epochs of the Annum is one form of the Latin noun meaning Year, not a form normally used for derivatives in modern languages the accusative singular The Devonian is a geologic period and system of the Paleozoic era spanning from to  million years ago. The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359 The Rugosa Rose is also sometimes just called "Rugosa" The Rugosa, also called the Tetracoralla, are an extinct order In Biology and Ecology, extinction is the cessation of existence of a Species or group of taxa. Late Cretaceous (100mya - 65mya refers to the second half of the Cretaceous Period, named after the famous white Chalk cliffs of southern England The Neogene is a geologic period and system starting 2303 ± 0 Scleractinia, also called Stony Corals, are exclusively marine animals they are very similar to Sea anemones but generate a hard skeleton

Not all reefs in the past were formed by corals: in the Early Cambrian (542-513 Ma) resulted from calcareous algae and archaeocyathids (small animals with conical shape, probably related to sponges) and in the Late Cretaceous (100 -65 Ma), when there also existed reefs formed by a group of bivalves called rudists; one of the valves formed the main conical structure and the other, much smaller valve acted as a cap. The Early Cambrian (also known as the Caerfai, Waucoban, or Georgian) is the first of three geological epochs of the Cambrian Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms The Archaeocyatha or archaeocyathids ("ancient cups" were Sessile The sponges or poriferans (from Latin porus "pore" and ferre "to bear" are Animals Late Cretaceous (100mya - 65mya refers to the second half of the Cretaceous Period, named after the famous white Chalk cliffs of southern England Bivalves are Molluscs belonging to the class Bivalvia. They have two-part shells and typically both valves are symmetrical along the hinge line Rudists are a group of bizarrely shaped marine Heterodont Bivalves that arose during the Jurassic, and became so diverse during the

See also

• Algae
• Black band disease
• Bruno Van Peteghem
• Coral
• Coral bleaching
• Coral rag
• Coral Reef Alliance
• Marine conservation
• Project AWARE
• Reef shark
• White band disease

References

General references

External links

• Reef Fest Concert Series Non-profit organization to benefit coral reef conservation globally during the International Year of the Reef 2008
• International Year of the Reef in 2008
• Moorea Coral Reef Long Term Ecological Research Site (US NSF)
• ARC Centre of Excellence for Coral Reef Studies
• NOAA's Coral-List Listserver for Coral Reef Information and News
• NOAA's Coral Reef Conservation Program
• NOAA's Coral Reef Information System
• NOAA Report: The State of Coral Reef Ecosystems of the United States and Pacific Freely Associated States: 2005
• ReefBase: A Global Information System on Coral Reefs
• National Coral Reef Institute Nova Southeastern University
• Global Coral Reef Alliance
• Global Coral Reef Monitoring Network (GCRMN)
• Marine Aquarium Council
• NCORE National Center for Coral Reef Research University of Miami
• The Coral Reef Alliance (CORAL)
• Science and Management of Coral Reefs in the South China Sea and Gulf of Thailand
• A special report on the plight of the planet's coral reefs—and how you can help—from Mother Jones magazine
• A guide to finding sources and literature about coral reefs
• NBII portal on coral reefs