Besides the White Pox Diease mentioned in one of the previous post, there are also many other Coral diseases.Below are information on the other diseases.
Sea Fan Browning & Fungus
1995 was the year REEF RELIEF's Craig Quirolo observed that the majority of purple sea fans were turning brown. The filter feeders appear to be "stuffed" with particulate matter. Some have lesions that create gaping holes while others were infected with a fungus that causes deep purple spots on the sea fan. Quirolo shared his data with Drew Harvell of Cornell University, who is studying the sea fans along with Kio Kim (Un Buffalo), and Garriett Smith (Un-N.C.). They have learned that the fungus attacking the fragile gorgonians is aspergillus, typically found in soil. Sea fans in Puerto Rico, the Bahamas and Jamaica are also turning brown.
Blackband Disease
Blackband disease has attacked boulder corals like the lesser and greater star corals for many years, but an acceleration of diseased coralheads began in the late 1980's at Keys reefs. The leading edge of the disease is a cyanobacteria. Healthy coral growth appears to mushroom up and around the dead area over time. Harold Hudson of the Florida Keys National Marine Sanctuary developed a method of preventing its spread by vacuuming the disease off corals and applying protective clay to the affected tissue. Since the disease is high in phosphates, REEF RELIEF introduced and fought hard for passage of a phosphate ban on soaps and detergents used throughout the Florida Keys that is one of the strongest phosphate bans in America.
Importance of coral reefs.
Coral reefs are important for many reasons.They provide shelter and protection for many different species of fish.They also protect coasts from strong currents and waves by slowing down the water before it gets to the shore.Coral reefs contain the largest variety of species of marine life in a very tiny area, and produce more living biomass than any other marine ecosystem. Coral reefs provide many free economic and environmental services, which make them the most valuable of all marine ecosystems in most countries . They are very important in controlling how much carbon dioxide is in the ocean water. Without them, the amount of carbon dioxide in the water would rise dramatically and that would affect all living things on Earth,not only that,fishes will also be left homeless.
The Great Barrier Reef is the only living thing on earth that can be seen from outer space!
600 continental islands and 350 coral cays are spread throughout the reef.
There are approximately 3400 individual reefs that make up the Barrier Reef.
That the Great Barrier Reef was declared World Heritage on 26th October 1981.
The reef stretches for more than 2300 kilometres, from near Fraser Island off the coast of Queensland Australia to the Papua New Guinean coastline.
Not all coral is hard,in fact some are soft and spongy.
coral facts
World's first coral reefs occurred about five hundred years ago,their first close relative developed in Europe 230 million years ago.The Great Barrier Reef is relatively young at just 500,000 years old. The current reef's structure is much younger at less than around 8,000 years old.most reefs have formed on hard surface ,like a base of an old reef that died when the sea level is low,or on the edge of a rocky island. It depends on how the reefs start out, several types of reefs can form. Coral reefs form in the deep ocean and are called atolls. The theories on how coral reefs form were first put forward by Charles Darwin (of The Origin of Species fame) who proposed that atolls form around the edges of high volcanic islands that gradually submerge beneath the sea with changes in sea level or subsidence of the land. Hence,an atoll starts life as a fringing reef, then it becomes more of a ring growing on the shrinking land-mass, until the land disappears and just the coral circle remains. In some cases, the coral growth is unable to keep pace with the sinking island, and sunken dead reefs have been found.
Formations of coral reefs
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.
Barrier reef – a reef separated from a mainland or island shore by a deep
lagoon (see
Great Barrier Reef).
Patch reef – an isolated, often circular reef, usually within a
lagoon or
embayment.
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.
Table reef – an isolated reef, approaching an atoll type, but without a lagoon
source:http://en.wikipedia.org/wiki/Coral_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 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. 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
source:http://en.wikipedia.org/wiki/Coral_reef
Coral reefs are
aragonite structures produced by living organisms, found in marine waters with little to no nutrients in the water. High nutrient levels such as those found in runoff from agricultural areas can harm the reef by encouraging the growth of
algae.
[1] In most reefs, the predominant organisms are stony
corals, colonial cnidarians that secrete an exoskeleton of
calcium carbonate. 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. Although corals are found both in temperate and tropical waters, shallow-water reefs are formed only in a zone extending at most from 30°N to 30°S of the equator. Tropical corals do not grow at depths of over 50 m (165 ft). Temperature has less of an effect on the distribution of tropical coral, but it is generally accepted that they do not exist in waters below 18
°C.
[2]. However,
deep water corals can exist at greater depths and colder temperatures. Although deep water corals also form reefs, very little is known about them.
[3]source:http://en.wikipedia.org/wiki/Coral_reef
Reefs in Singapore
There was once over 60 offshore islands and patch reefs around Singapore. However, since the mid 1970s, major land reclamation was carried out on the mainland as well as the offshore southern islands. Most of the southern islands were reclaimed, adding 1695 ha to Singapore's total land area. Some islands were merged as a result and the reef flats of many islands were reclaimed. Many coral reef organisms were smothered by the reclamation, while others were severely affected by the resulting increase in underwater sediments. Since 1986, most coral reefs in Singapore have lost up to 65% of their live coral cover. Visibility also dropped from 10m in the 1960s to 2m or less today.
Endangered coral specie
Queen Conch
Conch is a mollusk, similar to the West Coast Abalone, encased in a beautiful shell. It is the symbol of the Florida Keys (and Key West), as well as the main ingredient in "Conch Chowder." Because of the extreme popularity of its ornamental shell and meat, the Conch has been over harvested and is subsequently now under state protection. Conch served in Florida restaurants comes from the Bahamas and other spots in the Caribbean where it is harvested from the wild, as well as grown in nurseries.
healthy corals
Out there in the sea, besides corals that are unhealthy, there are healthy ones too!Here are some information about two healthy corals species
Boulder Star Coral (Montastraea annularis)Colonies grow in irregular mounds. The long thick columns have enlarged dome tops. The surfaces are rough and in plate-like sheets.Size: 1-10 feetColor: Green to brown, yellow brown and greyHabitat: 20-70 feet, they are often the most common coral at this medium depth
Boulder brain corals Forms colonies form large rounded domes. The surface is covered with a convoluted system of ridges and valleys looking very much like a brain. Boulder brain coral is also commonly known as Giant Brain Coral.Size: 2-7ft
Adapted from:http://www.reefrelief.org/Image_archive/healthy/healthy_index.html
white pox disease
1995 was the year REEF RELIEF's Craig Quirolo observed that the majority of purple sea fans were turning brown. The filter feeders appear to be "stuffed" with particulate matter. Some have lesions that create gaping holes while others were infected with a fungus that causes deep purple spots on the sea fan. Quirolo shared his data with Drew Harvell of Cornell University, who is studying the sea fans along with Kio Kim (Un Buffalo), and Garriett Smith (Un-N.C.). They have learned that the fungus attacking the fragile gorgonians is aspergillus, typically found in soil. Sea fans in Puerto Rico, the Bahamas and Jamaica are also turning brown.
Threats to reef
Threats Water Quality Decline: Corals require clear, clean, nutrient-free waters to thrive. Algal blooms caused by excess nutrients in the water column out-compete slow growing corals for habitat and reduce oxygen levels, decreasing visibility, increasing chlorophyll levels, and inhibiting photosynthesis dependent on sunlight. The kinds and extent of diseases attacking corals have increased in recent years and have reduced coral coverage. As oxygen levels are reduced, fish and other sealife cannot survive at the reef.
Pollution: Coral reefs are impacted by multiple stressors including agricultural runoff from pesticides and fertilizers, inadequate sewage and stormwater treatment, siltation from coastal development and beach renourishment projects, contamination from petroleum products, and sewage, oil and toxic discharges from boats, including antifouling paint applied to boat bottoms.
Overharvesting: As fish and other wildlife populations decline, the delicate predator-prey balance of life on the reef is upset. Experts warn that fish populations are at risk because maximum sustainable yields for many species around the world, including some that are endangered, have been exceeded. Destructive fishing techniques such as the use of cyanide and trawling gear damage reef habitat. The outright depletion caused by the harvest of coral and live rock for construction and the aquarium/curio trade has destroyed many reefs around the world.
Physical Damage: Anchors dropped on reefs, as well as accidental boat groundings and propellor dredging can crush and scar coralheads, destroying years of growth. Diver/snorkeler impacts from fins, hands, equipment or standing on corals can crush the fragile living coral polyps. Marine debris, especially plastics and monofilament line, can smother or abrade corals and is deadly for birds, fish and turtles that become entangled in it or mistake it for food and ingest it. Storms and hurricanes wreak extensive damage on coral reefs, which serve as a barrier to adjacent lands.
Global Climate Change: Rising sea temperatures cause coral bleaching, stressing corals that expel their symbiotic algae, lose their color, and lose their vitality. Corals are the canaries in the coal mine for our planet’s health.
source:
http://www.reefrelief.org/coralreef/threats.shtml
coral reproduction
Corals reproduce by asexually or sexually.Some of them divide to form new individuals,which is known as asexual reproduction.Mass spawning, where polyps release millions of eggs and sperm,is the way corals reproduce sexually.Polyps are either male or female or both male and female.The eggs and sperm flot to the surface after they are released. The fertilised eggs that escape predation by other animals hatch into larvae and drift with the plankton. Those that survive will settle on the reef then begin new coral colonies.
The world's first coral reefs occurred about 500 million years ago, and the first close relatives of modern corals developed in southern Europe about 230 million years ago. By comparison, the Great Barrier Reef is relatively young at just 500,000 years old. The current reef's structure is much younger at less than around 8,000 years old.Most modern reefs have formed on hard surfaces in the ocean, such as a base of an old reef that died during a period when sea level was lower, or the edge of a rocky island. Depending on how they start out, several types of reefs can form. Some coral reefs form in the deep ocean and are called atolls. The theories on how coral reefs form were first put forward by Charles Darwin (of The Origin of Species fame) who proposed that atolls form around the edges of high volcanic islands that gradually submerge beneath the sea with changes in sea level or subsidence of the land. Thus an atoll starts life as a fringing reef, then becomes more of a ring growing on the shrinking land-mass, until the land disappears and just the coral circle remains. In some cases, the coral growth is unable to keep pace with the sinking island, and sunken dead reefs have been found. Class: Anthozoa [includes corals, anemones and sea pens]Habitat: Coral reefs are found in shallow water, ranging to depths of 60 m. Some species prefer either cooler temperate water while others are found along tropical reefs, such as the Great Barrier Reef, with waters ranging in temperatures from 18 - 33 °C. Living in colonies: They generally occur in large numbers as colonies of individual polyps linked by tissue. Resources, such as food, are then shared amongst the individuals in the colony. Coral Size: Individual polyps range from 3 - 56 mm in diameter or height; while colony size varies from 75 mm -1500 mm (1.5 m) in width, height or length.
Some corals have a mutualistic relationship with algae called zooxanthellae. A mutualistic relationship is one where both parties benefit from their partnership. The algae use sunlight and the polyp’s waste products to make oxygen and food. These substances leak into the surrounding tissues of the polyp and can provide up to 98% of the polyp’s dietary requirements. These corals are found in shallow water, as they require sunlight to survive. They are generally fawn, brown or green in colour, due to the yellow-brown colour of the zooxanthellae. Stinging cells: All Cnidarians have characteristic stinging cells called nematocysts in the tentacles and body wall. Each nematocyst cell contains a coiled thread under pressure, which is ejected from the cell when triggered by touch. These stinging cells are used for catching prey and for defense, some having barbed ends connected to poison sacs, while others are sticky.
source:
http://www.barrierreefaustralia.com/the-great-barrier-reef/coralfacts.htm
