Environmental issues with coral reefs
Encyclopedia
Human impact on coral reefs is significant. Coral reef
s are dying around the world. In particular, coral mining, pollution
(organic and non-organic), overfishing
, blast fishing
and the digging of canal
s and access into islands and bays are serious threats to these ecosystems. Coral reefs also face high dangers from pollution, diseases, destructive fishing practices and warming oceans. In order to find answers for these problems, researchers study the various factors that impact reefs. The list of factors is long, including the ocean's role as a carbon dioxide sink
, atmospheric changes, ultraviolet light, ocean acidification
, biological virus
, impacts of dust storms carrying agents to far flung reefs, pollutants, algal bloom
s and others. Reefs are threatened well beyond coastal areas.
General estimates show approximately 10% world's coral reefs are already dead. 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 80% of reefs are endangered
.
and tropical Pacific, direct contact between coral and 40–70% of common seaweed
s cause bleaching
and death of coral tissue via allelopathic competition. The lipid-soluble extracts of seaweeds that harmed coral tissues also produced rapid bleaching. At these sites bleaching and mortality was limited to areas of direct contact with seaweeds or their extracts. The seaweed ten expanded to occupy the dead coral's habitat. However, as of 2009, only 4% of coral reefs worldwide had more than 50% algal coverage. Further, there is no recent global trend towards algal dominance.
Competitive seaweed and other algae
thrive in nutrient-rich waters in the absence of sufficient herbivorous
predators. Herbivores include fish such as parrotfish
, surgeonfish, tang
s and unicornfish.
, particularly selective overfishing, can unbalance coral ecosystems by encouraging the excessive growth of coral predators. Predators that eat living coral, such as the crown-of-thorns starfish
, are called corallivores. Coral reefs are built from stony coral, which evolved with large amounts of the wax
cetyl palmitate
in their tissues. Most predators find this wax indigestible. The crown-of-thorns starfish is a large (up to one metre) starfish protected by long, venomous spines. Its enzyme
system dissolves the wax
in stony corals, and allows the starfish to feed on the living animal. Starfish face predators of their own, such as the giant triton sea snail
. However, the giant triton is valued for its shell
and has been overfished. As a result, crown-of-thorns starfish populations can periodically grow unchecked, devastating reefs.
fish species can reproduce in aquaria (such as Pomacentridae
), most (95%) are collected from coral reefs. Intense harvesting, especially in South-East Asia (including Indonesia and the Philippines), damages the reefs. This is aggravated by destructive fishing practices
, such as cyanide
and blast fishing
. Most (80–90%) aquarium fish from the Philippines are captured with sodium cyanide
. This toxic chemical is dissolved in sea water and released into areas where fish shelter. It narcotizes the fish, which are then easily captured. However, most fish collected with cyanide die a few months later from liver
damage. Moreover, many non-marketable specimens die in the process. It is estimated that 4,000 or more Filipino fish collectors have used over 1000000 kilograms (2,204,622.6 lb) of cyanide on Philippine reefs alone, about 150,000 kg per year. A major catalyst of cyanide fishing
is poverty within fishing communities. In countries like the Philippines
that regularly employ cyanide, more than thirty percent of the population lives below the poverty line.
Dynamite fishing
is another destructive method for gathering fish. Sticks of dynamite
, grenade
s, or home-made explosives are detonated in the water. This method of fishing kills the fish within the main blast area, along with many unwanted reef animals. The blast also kills the corals in the area, eliminating the reef's structure, destroying habitat for the remaining fish and other animals important for reef health. Muroami
is the destructive practice of covering reefs with nets and dropping large stones onto the reef to produce a flight response among the fish. The stones break and kill the coral. Muroami was generally outlawed in the 1980s.
Fishing gear damages reefs via direct physical contact with the reef structure and substrate. Gill nets, fish traps, and anchors break branching coral and cause coral death through entanglement. When fishermen drop lines by coral reefs, the lines entangle the coral. The fisher cuts the line and abandons it, leaving it attached to the reef. The discarded lines abrade coral polyp
s and upper tissue layers. Corals are able to recover from small lesions, but larger and recurrent damage complicates recovery.
Bottom dragging gear such as beach seines can damage corals by abrasion and fracturing. A beach seine is a long net about 150 metres (492.1 ft) with a mesh size of 3 centimetres (1.2 in) and a weighted line to hold the net down while it is dragged across the substrate and is one of the most destructive types of fishing gear on Kenya’s reefs.
Bottom trawling
in deep oceans destroys cold–water and deep–sea corals. Historically, industrial fishers avoided coral because their nets would get caught on the reefs. In the 1980s, "rock–hopper" trawls attached large tires and rollers to allow the nets to roll over rough surfaces. Fifty-five percent of Alaskan cold–water coral that was damaged by one pass from a bottom trawl had not recovered a year later. Northeast Atlantic reefs bear scars up to 4 kilometres (2.5 mi) long. In Southern Australia, 90 percent of the surfaces on coral seamount
s are now bare rock. Even in the Great Barrier Reef World Heritage Area, seafloor trawling for prawns and scallops is causing localized extinction of some coral species.
Reefs in close proximity to human populations are subject to poor water quality from land- and marine-based sources. In the Caribbean, approximately 80 percent of ocean pollution originates from activities on land. Pollution arrives from land via runoff
, the wind and "injection" (deliberate introduction, e.g., drainpipes).
Runoff brings with it sediment from erosion
and land-clearing, nutrients and pesticides from agriculture
, wastewater
, industrial effluent
and miscellaneous material such as petroleum residue and trash that storms wash away. Some pollutants consume oxygen
and lead to eutrophication
, killing coral and other reef inhabitants.
An increasing fraction of the global population lives in coastal areas. Without appropriate precautions, development (e.g., buildings and paved roads) increases the fraction of rainfall and other water sources that enter the ocean as runoff by decreasing the land's ability to absorb it.
Pollution can introduce pathogen
s. For example, Aspergillus
sydowii has been associated with a disease in sea fan
s, and Serratia marcescens
, has been linked to the coral disease white pox.
Reefs in close proximity to human populations can be faced with local stresses, including poor water quality from land-based sources of pollution. Copper
, a common industrial pollutant has been shown to interfere with the life history
and development of coral polyps.
In addition to runoff, wind blows material into the ocean. This material may be local or from other regions. For example, dust from the Sahara
moves to the Caribbean
and Florida
. Dust also blows from the Gobi and Taklamakan
deserts across Korea
, Japan
, and the Northern Pacificto the Hawaiian Islands
. Since 1970, dust deposits have grown due to drought periods in Africa. Dust transport to the Caribbean and Florida varies from year to year with greater flux during positive phases of the North Atlantic Oscillation
. The USGS links dust events to reduced health of coral reefs across the Caribbean and Florida, primarily since the 1970s. Dust from the 1883 eruption of Krakatoa
in Indonesia
appeared in the annular bands of the reef-building coral Montastraea annularis
from the Florida Reeftract.
Sediment smothers corals and interferes with their ability to feed and reproduce. Pesticides can interfere with coral reproduction and growth.
and phosphorus
can cause eutrophication
, upsetting the balance of the reef by enhancing algal growth and crowding out corals.This nutrient–rich water can enable blooms of fleshy algae
and phytoplankton
to thrive off coasts. These blooms can create hypoxic
conditions by using all available oxygen
. Biologically available nitrogen (nitrate plus ammonia
) needs to be below 1.0 micromole per liter
(less than 0.014 parts per million of nitrogen), and biologically available phosphorus (orthophosphate plus dissolved organic phosphorus) needs to be below 0.1 micromole per liter (less than 0.003 parts per million of phosphorus). In addition concentrations of chlorophyll (in the microscopic plants called phytoplankton) needs to be below 0.5 parts per billion. Both plants also obscure sunlight, killing both fish and coral. High nitrate levels are specifically toxic to corals, while phosphates slow down skeletal growth.
Excess nutrients can intensify existing disease, including potentially doubling the spread of Aspergillosis
, a fungal infection that kills soft corals such as sea fans, and increasing yellow band disease, a bacterial infection that kills reef-building hard corals by fifty percent.
Plastic debris kills several reef species. Derelict (abandoned) fishing nets and other gear—often called "ghost nets" because they still catch fish and other marine life despite being abandoned—can entangle and kill reef organisms and break or damage reefs. Even remote reef systems suffer the effects of marine debris. Reefs in the Northwestern Hawaiian Islands
are particularly prone to the accumulation of marine debris because of their central location in the North Pacific Gyre
. From 2000 to 2006, NOAA and partners removed over 500 tons of marine debris there.
Rising sea levels due to climate change requires coral to grow to stay close enough to the surface to continue photosynthesis
. Also, water temperature changes can induce coral bleaching
as happened during the 1998 and 2004 El Niño years, in which sea surface temperature
s rose well above normal, bleaching or killing many reefs. High sea surface temperature (SST) coupled with high irradiance (light intensity), triggers the loss of zooxanthellae, a symbiotic algae, and its dinoflagellate
pigmentation in corals, turning coral white. Zooxanthellae provide up to 90% of their hosts' energy supply. Healthy reefs can often recover from bleaching if water temperatures cool. However, recovery may not be possible if levels rise to 500 ppm
because concentrations of carbonate ions may then be too low.
Warming seawater may also encourage an emerging problem: coral disease. Weakened by warm water, coral is much more prone to diseases including black band disease
, white band disease
and skeletal eroding band
. If global temperatures increase by 2 °C during the twenty-first century, coral may not be able to adapt quickly enough.
A 2010 report by the Institute of Physics
predicts that unless the national targets set by the Copenhagen Accord
are amended to eliminate loopholes, then by 2100 global temperatures could rise by 4.2°C and result in an end to coral reefs.
Ocean acidification
results from increases in atmospheric carbon dioxide
. Oceans absorb around one–third of the increase. The dissolved gas reacts with the water to form carbonic acid
, and thus acidifies the ocean. This decreasing pH
is another issue for coral reefs.
Ocean surface pH is estimated to have decreased from about 8.25 to 8.14 since the beginning of the industrial era, and a further drop of 0.3–0.4 units is expected. Before the industrial age the conditions for calcium carbonate
production were typically stable in surface waters since the carbonate
ion
is at supersaturated
concentrations. However, as the ionic concentration falls, carbonate becomes under-saturated, making calcium carbonate structures vulnerable to dissolution. Corals experience reduced calcification or enhanced dissolution when exposed to elevated .
Bamboo coral
is a deep water coral
which produces growth rings similar to trees. The growth rings illustrate growth rate changes as deep sea conditions change, including changes due to ocean acidification. Specimens as old as 4,000 years have given scientists "4,000 years worth of information about what has been going on in the deep ocean interior".
, have been destroyed. Both the loss of wetlands, mangrove habitats and seagrass meadows affect the water quality
of inshore reefs.
Coral mining
is another threat. Both small scale harvesting by villagers and industrial scale mining by companies are serious threats. Mining is usually done to produce construction material which is valued as much as 50% cheaper than other rocks, such as from quarries
. The rocks are ground and mixed with other materials, like cement to make concrete. Ancient coral used for construction is known as coral rag
. Building directly on the reef also takes its toll, altering water circulation and the tides which bring the nutrients to the reef. The pressing reason for building on reefs is simply lack of space.
Boats and ships require access points into bays and islands to load and unload cargo and people. For this, parts of reefs are often chopped away to clear a path. Negative consequences can include altered water circulation and altered tidal
patterns which can disrupt the reef's nutrient supply; sometimes destroying a great part of the reef. Fishing vessel
s and other large boats occasionally run aground on a reef. Two types of damage can result. Collision damage occurs when a coral reef is crushed and split by a vessel's hull into multiple fragments. Scarring occurs when boat propellers tear off the live coral and expose the skeleton. The physical damage can be noticed as striations. Mooring causes damage which can be reduced by using mooring buoy
s. Buoys can attach to the seafloor using concrete blocks as weights or by penetrating the seafloor, which further reduces damage.
Coral in Taiwan is being threatened by the influx of human population growth. Since 2007, several local environmental groups conducted research and found that much of the coral populations are being affected by untreated sewage, an influx of tourists taking corals for souvenirs, without fully understanding the destructive impact on the coral's ecological system. Researchers reported to the Taiwanese government that many coral populations have turned black in the southeast coast of Taiwan. Potentially, this could lead to loss of food supply, medicinal sources and tourism due to the breakdown of the food chain.
marine species is the IUCN Red List of Threatened Species. This list is the foundation for marine conservation priorities worldwide. A species is listed in the threatened category if it is considered to be critically endangered, endangered
, or vulnerable
. Other categories are near threatened
and data deficient
. By 2008, the IUCN had assessed all 845 known reef-building corals species, marking 27% as Threatened
20% as near threatened
and 17% as data deficient
.
The coral triangle
(Indo-Malay-Philippine archipelago) region has the highest number of reef-building coral species in threatened category as well as the highest coral species diversity. The loss of coral reef ecosystems will have devastating effects on many marine species, as well as on people that depend on reef resources for their livelihoods.
is the world's largest coral reef
system. The reef is located in the Coral Sea
. A large part of the reef is protected by the Great Barrier Reef Marine Park
. Particular environmental pressures include runoff, salinity fluctuations, climate change, cyclic crown-of-thorns outbreaks, overfishing, and spills or improper ballast discharge.
practices (such as cyanide
and blast fishing
), overfishing
, sedimentation, pollution and bleaching. Activities including education, regulation and the establishment of marine protected area
s help protect these reefs.
is home to one third of the world's corals covering nearly 85000 square kilometres (32,818.7 sq mi) and one quarter of its fish species
. Indonesia's coral reefs are located in the heart of the Coral Triangle
and have fallen victim to destructive fishing, tourism and bleaching. Data from 414 reef monitoring stations in 2000 found that only 6% are in excellent condition, while 24% are in good condition, and approximately 70% are in poor to fair condition.
, the world's largest reef conservation
organization
, stated that only 5% of Philippines
27000 square kilometres (10,424.8 sq mi) 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
. Philippine coral reefs is Asia
's second largest.
are being threatened by human population growth. Many corals are affected by untreated sewage and souvenir-hunting tourists, not knowing that this practice destroys habitat and causes disease. Many corals have turned black from disease off Taiwan's southeast coast.
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s are dying around the world. In particular, coral mining, pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
(organic and non-organic), overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
, blast fishing
Blast fishing
Blast fishing or dynamite fishing is the practice of using explosives to stun or kill schools of fish for easy collection. This often illegal practice can be extremely destructive to the surrounding ecosystem, as the explosion often destroys the underlying habitat that supports the fish...
and the digging of canal
Canal
Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...
s and access into islands and bays are serious threats to these ecosystems. Coral reefs also face high dangers from pollution, diseases, destructive fishing practices and warming oceans. In order to find answers for these problems, researchers study the various factors that impact reefs. The list of factors is long, including the ocean's role as a carbon dioxide sink
Carbon dioxide sink
A carbon sink is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. The process by which carbon sinks remove carbon dioxide from the atmosphere is known as carbon sequestration...
, atmospheric changes, ultraviolet light, ocean acidification
Ocean acidification
Ocean acidification is the name given to the ongoing decrease in the pH and increase in acidity of the Earth's oceans, caused by the uptake of anthropogenic carbon dioxide from the atmosphere....
, biological virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
, impacts of dust storms carrying agents to far flung reefs, pollutants, algal bloom
Algal bloom
An algal bloom is a rapid increase or accumulation in the population of algae in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Typically, only one or a small number of phytoplankton species are involved, and some blooms may be recognized by discoloration...
s and others. Reefs are threatened well beyond coastal areas.
General estimates show approximately 10% world's coral reefs are already dead. 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
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
, where 80% of reefs are endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.
Competition
In the Caribbean SeaCaribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
and tropical Pacific, direct contact between coral and 40–70% of common seaweed
Seaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
s cause bleaching
Coral bleaching
Coral bleaching is the loss of intracellular endosymbionts through either expulsion or loss of algal pigmentation.The corals that form the structure of the great reef ecosystems of tropical seas depend upon a symbiotic relationship with unicellular flagellate protozoa, called zooxanthellae, that...
and death of coral tissue via allelopathic competition. The lipid-soluble extracts of seaweeds that harmed coral tissues also produced rapid bleaching. At these sites bleaching and mortality was limited to areas of direct contact with seaweeds or their extracts. The seaweed ten expanded to occupy the dead coral's habitat. However, as of 2009, only 4% of coral reefs worldwide had more than 50% algal coverage. Further, there is no recent global trend towards algal dominance.
Competitive seaweed and other algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
thrive in nutrient-rich waters in the absence of sufficient herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
predators. Herbivores include fish such as parrotfish
Parrotfish
Parrotfishes are a group of fishes that traditionally had been considered a family , but now often are considered a subfamily of the wrasses. They are found in relatively shallow tropical and subtropical oceans throughout the world, but with the largest species richness in the Indo-Pacific...
, surgeonfish, tang
Tang
-Chinese name:* Tang Dynasty , Chinese dynasty* Later Tang Dynasty , Turkic dynasty in ancient China* King Tang of Shang , the Shang dynasty ruler, who lived around 1660 BCE...
s and unicornfish.
Predation
OverfishingOverfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
, particularly selective overfishing, can unbalance coral ecosystems by encouraging the excessive growth of coral predators. Predators that eat living coral, such as the crown-of-thorns starfish
Crown-of-thorns starfish
The crown-of-thorns starfish is a large nocturnal sea star that preys upon coral polyps. The crown-of-thorns receives its name from venomous thorn-like spines that cover its body. It is endemic to tropical coral reefs in the Red Sea, the Indian Ocean, and the Pacific Ocean...
, are called corallivores. Coral reefs are built from stony coral, which evolved with large amounts of the wax
Wax
thumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...
cetyl palmitate
Cetyl palmitate
Cetyl palmitate is the ester derived from palmitic acid and cetyl alcohol. It is the primary constituent of spermaceti, the wax found in the skull of sperm whales....
in their tissues. Most predators find this wax indigestible. The crown-of-thorns starfish is a large (up to one metre) starfish protected by long, venomous spines. Its enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
system dissolves the wax
Wax
thumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...
in stony corals, and allows the starfish to feed on the living animal. Starfish face predators of their own, such as the giant triton sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
. However, the giant triton is valued for its shell
Mollusc shell
The mollusc shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes...
and has been overfished. As a result, crown-of-thorns starfish populations can periodically grow unchecked, devastating reefs.
Fishing practices
Although some aquariumAquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
fish species can reproduce in aquaria (such as Pomacentridae
Pomacentridae
Pomacentridae are a family of perciform fish, comprising the damselfishes and clownfishes. They are primarily marine, while a few species inhabit freshwater and brackish environments . They are noted for their hardy constitutions and territoriality...
), most (95%) are collected from coral reefs. Intense harvesting, especially in South-East Asia (including Indonesia and the Philippines), damages the reefs. This is aggravated by destructive fishing practices
Destructive fishing practices
The phrase destructive fishing practices has been featured in international fisheries literature for around three decades. No widely accepted definition of the phrase exists, and this will almost certainly remain the situation, given very different national and industry perspectives...
, such as cyanide
Cyanide fishing
Cyanide fishing is a method of collecting live fish mainly for use in aquariums, which involves spraying a sodium cyanide mixture into the desired fish's habitat in order to stun the fish...
and blast fishing
Blast fishing
Blast fishing or dynamite fishing is the practice of using explosives to stun or kill schools of fish for easy collection. This often illegal practice can be extremely destructive to the surrounding ecosystem, as the explosion often destroys the underlying habitat that supports the fish...
. Most (80–90%) aquarium fish from the Philippines are captured with sodium cyanide
Sodium cyanide
Sodium cyanide is an inorganic compound with the formula NaCN. This highly toxic colorless salt is used mainly in gold mining but has other niche applications...
. This toxic chemical is dissolved in sea water and released into areas where fish shelter. It narcotizes the fish, which are then easily captured. However, most fish collected with cyanide die a few months later from liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
damage. Moreover, many non-marketable specimens die in the process. It is estimated that 4,000 or more Filipino fish collectors have used over 1000000 kilograms (2,204,622.6 lb) of cyanide on Philippine reefs alone, about 150,000 kg per year. A major catalyst of cyanide fishing
Cyanide fishing
Cyanide fishing is a method of collecting live fish mainly for use in aquariums, which involves spraying a sodium cyanide mixture into the desired fish's habitat in order to stun the fish...
is poverty within fishing communities. In countries like the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
that regularly employ cyanide, more than thirty percent of the population lives below the poverty line.
Dynamite fishing
Blast fishing
Blast fishing or dynamite fishing is the practice of using explosives to stun or kill schools of fish for easy collection. This often illegal practice can be extremely destructive to the surrounding ecosystem, as the explosion often destroys the underlying habitat that supports the fish...
is another destructive method for gathering fish. Sticks of dynamite
Dynamite
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
, grenade
Grenade
A grenade is a small explosive device that is projected a safe distance away by its user. Soldiers called grenadiers specialize in the use of grenades. The term hand grenade refers any grenade designed to be hand thrown. Grenade Launchers are firearms designed to fire explosive projectile grenades...
s, or home-made explosives are detonated in the water. This method of fishing kills the fish within the main blast area, along with many unwanted reef animals. The blast also kills the corals in the area, eliminating the reef's structure, destroying habitat for the remaining fish and other animals important for reef health. Muroami
Muroami
The muro-ami fishing technique, employed on coral reefs in Southeast Asia, uses an encircling net together with pounding devices. These devices usually comprise large stones fitted on ropes that are pounded onto the coral reefs. They can also consist of large heavy blocks of cement that are...
is the destructive practice of covering reefs with nets and dropping large stones onto the reef to produce a flight response among the fish. The stones break and kill the coral. Muroami was generally outlawed in the 1980s.
Fishing gear damages reefs via direct physical contact with the reef structure and substrate. Gill nets, fish traps, and anchors break branching coral and cause coral death through entanglement. When fishermen drop lines by coral reefs, the lines entangle the coral. The fisher cuts the line and abandons it, leaving it attached to the reef. The discarded lines abrade coral polyp
Polyp
A polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are approximately cylindrical in shape and elongated at the axis of the body...
s and upper tissue layers. Corals are able to recover from small lesions, but larger and recurrent damage complicates recovery.
Bottom dragging gear such as beach seines can damage corals by abrasion and fracturing. A beach seine is a long net about 150 metres (492.1 ft) with a mesh size of 3 centimetres (1.2 in) and a weighted line to hold the net down while it is dragged across the substrate and is one of the most destructive types of fishing gear on Kenya’s reefs.
Bottom trawling
Trawling
Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net that is used for trawling is called a trawl....
in deep oceans destroys cold–water and deep–sea corals. Historically, industrial fishers avoided coral because their nets would get caught on the reefs. In the 1980s, "rock–hopper" trawls attached large tires and rollers to allow the nets to roll over rough surfaces. Fifty-five percent of Alaskan cold–water coral that was damaged by one pass from a bottom trawl had not recovered a year later. Northeast Atlantic reefs bear scars up to 4 kilometres (2.5 mi) long. In Southern Australia, 90 percent of the surfaces on coral seamount
Seamount
A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface , and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of depth. They are defined by oceanographers as...
s are now bare rock. Even in the Great Barrier Reef World Heritage Area, seafloor trawling for prawns and scallops is causing localized extinction of some coral species.
Pollution
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
, the wind and "injection" (deliberate introduction, e.g., drainpipes).
Runoff brings with it sediment from erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
and land-clearing, nutrients and pesticides from agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
, wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
, industrial effluent
Effluent
Effluent is an outflowing of water or gas from a natural body of water, or from a human-made structure.Effluent is defined by the United States Environmental Protection Agency as “wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers...
and miscellaneous material such as petroleum residue and trash that storms wash away. Some pollutants consume oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
and lead to eutrophication
Eutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...
, killing coral and other reef inhabitants.
An increasing fraction of the global population lives in coastal areas. Without appropriate precautions, development (e.g., buildings and paved roads) increases the fraction of rainfall and other water sources that enter the ocean as runoff by decreasing the land's ability to absorb it.
Pollution can introduce pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
s. For example, Aspergillus
Aspergillus
Aspergillus is a genus consisting of several hundred mold species found in various climates worldwide. Aspergillus was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli...
sydowii has been associated with a disease in sea fan
Sea fan
A gorgonian, also known as sea whip or sea fan, is an order of sessile colonial cnidarian found throughout the oceans of the world, especially in the tropics and subtropics. Gorgonians are similar to the sea pen, another soft coral. Individual tiny polyps form colonies that are normally erect,...
s, and Serratia marcescens
Serratia marcescens
Serratia marcescens is a species of Gram-negative, rod-shaped bacterium in the family Enterobacteriaceae. A human pathogen, S. marcescens is involved in nosocomial infections, particularly catheter-associated bacteremia, urinary tract infections and wound infections, and is responsible for 1.4% of...
, has been linked to the coral disease white pox.
Reefs in close proximity to human populations can be faced with local stresses, including poor water quality from land-based sources of pollution. Copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
, a common industrial pollutant has been shown to interfere with the life history
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
and development of coral polyps.
Sahara
The Sahara is the world's second largest desert, after Antarctica. At over , it covers most of Northern Africa, making it almost as large as Europe or the United States. The Sahara stretches from the Red Sea, including parts of the Mediterranean coasts, to the outskirts of the Atlantic Ocean...
moves to the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
and Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. Dust also blows from the Gobi and Taklamakan
Taklamakan
The Taklamakan Desert , also known as Taklimakan and Teklimakan, is a desert in Central Asia, in the Xinjiang Uyghur Autonomous Region of the People's Republic of China...
deserts across Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, and the Northern Pacificto the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
. Since 1970, dust deposits have grown due to drought periods in Africa. Dust transport to the Caribbean and Florida varies from year to year with greater flux during positive phases of the North Atlantic Oscillation
North Atlantic oscillation
The North Atlantic oscillation is a climatic phenomenon in the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level between the Icelandic low and the Azores high. Through east-west oscillation motions of the Icelandic low and the Azores high, it controls the...
. The USGS links dust events to reduced health of coral reefs across the Caribbean and Florida, primarily since the 1970s. Dust from the 1883 eruption of Krakatoa
Krakatoa
Krakatoa is a volcanic island made of a'a lava in the Sunda Strait between the islands of Java and Sumatra in Indonesia. The name is used for the island group, the main island , and the volcano as a whole. The island exploded in 1883, killing approximately 40,000 people, although some estimates...
in Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
appeared in the annular bands of the reef-building coral Montastraea annularis
Montastraea annularis
Montastraea annularis, commonly known as the boulder star coral, is a species of coral that lives in the western Atlantic Ocean and is the most thoroughly studied and most abundant species of reef-building coral in the Caribbean to date. It also has a comprehensive fossil record within the Caribbean...
from the Florida Reeftract.
Sediment smothers corals and interferes with their ability to feed and reproduce. Pesticides can interfere with coral reproduction and growth.
Excess nutrients
Excess nutrients, particularly nitrogenNitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
and phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
can cause eutrophication
Eutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...
, upsetting the balance of the reef by enhancing algal growth and crowding out corals.This nutrient–rich water can enable blooms of fleshy algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and phytoplankton
Phytoplankton
Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
to thrive off coasts. These blooms can create hypoxic
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
conditions by using all available oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
. Biologically available nitrogen (nitrate plus ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
) needs to be below 1.0 micromole per liter
Litér
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(less than 0.014 parts per million of nitrogen), and biologically available phosphorus (orthophosphate plus dissolved organic phosphorus) needs to be below 0.1 micromole per liter (less than 0.003 parts per million of phosphorus). In addition concentrations of chlorophyll (in the microscopic plants called phytoplankton) needs to be below 0.5 parts per billion. Both plants also obscure sunlight, killing both fish and coral. High nitrate levels are specifically toxic to corals, while phosphates slow down skeletal growth.
Excess nutrients can intensify existing disease, including potentially doubling the spread of Aspergillosis
Aspergillosis
Aspergillosis is the name given to a wide variety of diseases caused by fungi of the genus Aspergillus. The most common forms are allergic bronchopulmonary aspergillosis, pulmonary aspergilloma and invasive aspergillosis. Most humans inhale Aspergillus spores every day...
, a fungal infection that kills soft corals such as sea fans, and increasing yellow band disease, a bacterial infection that kills reef-building hard corals by fifty percent.
Marine debris
Marine debris is any solid object that enters coastal and ocean waters. Debris may arrive directly from a ship or indirectly when washed out to sea via rivers, streams, and storm drains. Human-made items tend to be the most harmful such as plastics (from bags to balloons, hard hats to fishing line), glass, metal, rubber (millions of tires!), and even entire vessels.Plastic debris kills several reef species. Derelict (abandoned) fishing nets and other gear—often called "ghost nets" because they still catch fish and other marine life despite being abandoned—can entangle and kill reef organisms and break or damage reefs. Even remote reef systems suffer the effects of marine debris. Reefs in the Northwestern Hawaiian Islands
Northwestern Hawaiian Islands
The Northwestern Hawaiian Islands or the Leeward Islands are the small islands and atolls in the Hawaiian island chain located northwest of the islands of Kauai and Niihau. They are administered by the U.S. state of Hawaii except Midway Atoll, which has temporary residential facilities and is...
are particularly prone to the accumulation of marine debris because of their central location in the North Pacific Gyre
North Pacific Gyre
The North Pacific Gyre, located in the northern Pacific Ocean, is one of the five major oceanic gyres. This gyre comprises most of the northern Pacific Ocean. It is the largest ecosystem on our planet...
. From 2000 to 2006, NOAA and partners removed over 500 tons of marine debris there.
Climate change
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
. Also, water temperature changes can induce coral bleaching
Coral bleaching
Coral bleaching is the loss of intracellular endosymbionts through either expulsion or loss of algal pigmentation.The corals that form the structure of the great reef ecosystems of tropical seas depend upon a symbiotic relationship with unicellular flagellate protozoa, called zooxanthellae, that...
as happened during the 1998 and 2004 El Niño years, in which sea surface temperature
Sea surface temperature
Sea surface temperature is the water temperature close to the oceans surface. The exact meaning of surface varies according to the measurement method used, but it is between and below the sea surface. Air masses in the Earth's atmosphere are highly modified by sea surface temperatures within a...
s rose well above normal, bleaching or killing many reefs. High sea surface temperature (SST) coupled with high irradiance (light intensity), triggers the loss of zooxanthellae, a symbiotic algae, and its dinoflagellate
Dinoflagellate
The dinoflagellates are a large group of flagellate protists. Most are marine plankton, but they are common in fresh water habitats as well. Their populations are distributed depending on temperature, salinity, or depth...
pigmentation in corals, turning coral white. Zooxanthellae provide up to 90% of their hosts' energy supply. Healthy reefs can often recover from bleaching if water temperatures cool. However, recovery may not be possible if levels rise to 500 ppm
PPM
- Culture :*Peter, Paul and Mary, a 1960s folk music trio*Picture Postcard Monthly, a magazine for collectors of postcards*Please Please Me, the first album by The Beatles- Health :*Permanent pacemaker or artificial pacemaker...
because concentrations of carbonate ions may then be too low.
Warming seawater may also encourage an emerging problem: coral disease. Weakened by warm water, coral is much more prone to diseases including black band disease
Black band disease
Black band disease is characterized by complete coral tissue degradation due to a pathogenic microbial consortium that appears as a dark red or black migrating microbial mat. The mat is present between apparently healthy coral tissue and freshly exposed coral skeleton.-Appearance:Black Band disease...
, white band disease
White band disease
White band disease is characterized by complete coral tissue degradation of Caribbean acroporid corals. Two species are affected, Acropora palmata and A. cervicornis . The disease exhibits a sharp demarcation between apparently healthy coral tissue and exposed coral skeleton...
and skeletal eroding band
Skeletal Eroding Band
Skeletal eroding band is a disease of corals that appears a black or dark gray band that slowly advances over corals, leaving a spotted region of dead coral in its wake...
. If global temperatures increase by 2 °C during the twenty-first century, coral may not be able to adapt quickly enough.
A 2010 report by the Institute of Physics
Institute of Physics
The Institute of Physics is a scientific charity devoted to increasing the practice, understanding and application of physics. It has a worldwide membership of around 40,000....
predicts that unless the national targets set by the Copenhagen Accord
Copenhagen Accord
The Copenhagen Accord is a document that delegates at the 15th session of the Conference of Parties to the United Nations Framework Convention on Climate Change agreed to "take note of" at the final plenary on 18 December 2009....
are amended to eliminate loopholes, then by 2100 global temperatures could rise by 4.2°C and result in an end to coral reefs.
Ocean acidification
Ocean acidification
Ocean acidification is the name given to the ongoing decrease in the pH and increase in acidity of the Earth's oceans, caused by the uptake of anthropogenic carbon dioxide from the atmosphere....
results from increases in atmospheric carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
. Oceans absorb around one–third of the increase. The dissolved gas reacts with the water to form carbonic acid
Carbonic acid
Carbonic acid is the inorganic compound with the formula H2CO3 . It is also a name sometimes given to solutions of carbon dioxide in water, because such solutions contain small amounts of H2CO3. Carbonic acid forms two kinds of salts, the carbonates and the bicarbonates...
, and thus acidifies the ocean. This decreasing pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
is another issue for coral reefs.
Ocean surface pH is estimated to have decreased from about 8.25 to 8.14 since the beginning of the industrial era, and a further drop of 0.3–0.4 units is expected. Before the industrial age the conditions for calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
production were typically stable in surface waters since the carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
is at supersaturated
Supersaturation
The term supersaturation refers to a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances...
concentrations. However, as the ionic concentration falls, carbonate becomes under-saturated, making calcium carbonate structures vulnerable to dissolution. Corals experience reduced calcification or enhanced dissolution when exposed to elevated .
Bamboo coral
Bamboo coral
Bamboo coral, family Isididae, is a family of mostly deep-sea coral of the phylum Cnidaria, class Anthozoa, and subclass Octocorallia. It is a commonly recognized inhabitant of the deep sea, due to the clearly articulated skeletons of the species. Deep water coral species such as this are...
is a deep water coral
Deep water coral
The habitat of deep water corals, also known as cold water corals, extends to deeper, darker parts of the oceans than tropical corals, ranging from near the surface to the abyss, beyond where water temperatures may be as cold as 4°C...
which produces growth rings similar to trees. The growth rings illustrate growth rate changes as deep sea conditions change, including changes due to ocean acidification. Specimens as old as 4,000 years have given scientists "4,000 years worth of information about what has been going on in the deep ocean interior".
Other issues
Within the last 20 years, once prolific seagrass meadows and mangrove forests, which absorb massive amounts of nutrients and sedimentSediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
, have been destroyed. Both the loss of wetlands, mangrove habitats and seagrass meadows affect the water quality
Water quality
Water quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...
of inshore reefs.
Coral mining
Coral sand
Coral sand is sand of particles originating in tropical and sub-tropical marine environments from bioerosion of limestone skeletal material of marine organisms. One example of this process is that of parrot fishes which bite off pieces of coral, digest the living tissue, and excrete the inorganic...
is another threat. Both small scale harvesting by villagers and industrial scale mining by companies are serious threats. Mining is usually done to produce construction material which is valued as much as 50% cheaper than other rocks, such as from quarries
Quarries
Quarries - The "Royal Quarries" — not found in Scripture — is the namegiven to the vast caverns stretching far underneath the northern hill, Bezetha, on which Jerusalem is built. Out of these mammoth caverns stones, a hard limestone, have been quarried in ancient times for the buildings in the...
. The rocks are ground and mixed with other materials, like cement to make concrete. Ancient coral used for construction is known as coral rag
Coral rag
Coral rag is a rubbly limestone composed of ancient coral reef material. The term also refers to the building blocks quarried from these strata which are an important local building material in areas such as the east African coast and the Caribbean basin .It is also the name of a member — the Coral...
. Building directly on the reef also takes its toll, altering water circulation and the tides which bring the nutrients to the reef. The pressing reason for building on reefs is simply lack of space.
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
patterns which can disrupt the reef's nutrient supply; sometimes destroying a great part of the reef. Fishing vessel
Fishing vessel
A fishing vessel is a boat or ship used to catch fish in the sea, or on a lake or river. Many different kinds of vessels are used in commercial, artisanal and recreational fishing....
s and other large boats occasionally run aground on a reef. Two types of damage can result. Collision damage occurs when a coral reef is crushed and split by a vessel's hull into multiple fragments. Scarring occurs when boat propellers tear off the live coral and expose the skeleton. The physical damage can be noticed as striations. Mooring causes damage which can be reduced by using mooring buoy
Buoy
A buoy is a floating device that can have many different purposes. It can be anchored or allowed to drift. The word, of Old French or Middle Dutch origin, is now most commonly in UK English, although some orthoepists have traditionally prescribed the pronunciation...
s. Buoys can attach to the seafloor using concrete blocks as weights or by penetrating the seafloor, which further reduces damage.
Coral in Taiwan is being threatened by the influx of human population growth. Since 2007, several local environmental groups conducted research and found that much of the coral populations are being affected by untreated sewage, an influx of tourists taking corals for souvenirs, without fully understanding the destructive impact on the coral's ecological system. Researchers reported to the Taiwanese government that many coral populations have turned black in the southeast coast of Taiwan. Potentially, this could lead to loss of food supply, medicinal sources and tourism due to the breakdown of the food chain.
Threatened species
The global standard for recording threatenedThreatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
marine species is the IUCN Red List of Threatened Species. This list is the foundation for marine conservation priorities worldwide. A species is listed in the threatened category if it is considered to be critically endangered, endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
, or vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
. Other categories are near threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
and data deficient
Data Deficient
Data Deficient is a category applied by the IUCN, other agencies, and individuals to a species when the available information is not sufficient for a proper assessment of conservation status to be made...
. By 2008, the IUCN had assessed all 845 known reef-building corals species, marking 27% as Threatened
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
20% as near threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
and 17% as data deficient
Data Deficient
Data Deficient is a category applied by the IUCN, other agencies, and individuals to a species when the available information is not sufficient for a proper assessment of conservation status to be made...
.
The coral triangle
Coral Triangle
The Coral Triangle is a geographical term so named as it refers to a roughly triangular area of the tropical marine waters of Indonesia, Malaysia, Papua New Guinea, Philippines, Solomon Islands and Timor-Leste that contain at least 500 species of reef-building corals in each ecoregion...
(Indo-Malay-Philippine archipelago) region has the highest number of reef-building coral species in threatened category as well as the highest coral species diversity. The loss of coral reef ecosystems will have devastating effects on many marine species, as well as on people that depend on reef resources for their livelihoods.
Issues by region
Australia
The Great Barrier ReefGreat Barrier Reef
The Great Barrier Reef is the world'slargest reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres over an area of approximately...
is the world's largest coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
system. The reef is located in the Coral Sea
Coral Sea
The Coral Sea is a marginal sea off the northeast coast of Australia. It is bounded in the west by the east coast of Queensland, thereby including the Great Barrier Reef, in the east by Vanuatu and by New Caledonia, and in the north approximately by the southern extremity of the Solomon Islands...
. A large part of the reef is protected by the Great Barrier Reef Marine Park
Great Barrier Reef Marine Park
The Great Barrier Reef Marine Park protects a large part of Australia's Great Barrier Reef from damaging activities. Fishing and the removal of artefacts or...
. Particular environmental pressures include runoff, salinity fluctuations, climate change, cyclic crown-of-thorns outbreaks, overfishing, and spills or improper ballast discharge.
Southeast Asia
Southeast Asian coral reefs are at risk from damaging fishingFishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....
practices (such as cyanide
Cyanide fishing
Cyanide fishing is a method of collecting live fish mainly for use in aquariums, which involves spraying a sodium cyanide mixture into the desired fish's habitat in order to stun the fish...
and blast fishing
Blast fishing
Blast fishing or dynamite fishing is the practice of using explosives to stun or kill schools of fish for easy collection. This often illegal practice can be extremely destructive to the surrounding ecosystem, as the explosion often destroys the underlying habitat that supports the fish...
), overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
, sedimentation, pollution and bleaching. Activities including education, regulation and the establishment of marine protected area
Marine Protected Area
Marine Protected Areas, like any protected area, are regions in which human activity has been placed under some restrictions in the interest of conserving the natural environment, it's surrounding waters and the occupant ecosystems, and any cultural or historical resources that may require...
s help protect these reefs.
Indonesia
IndonesiaIndonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
is home to one third of the world's corals covering nearly 85000 square kilometres (32,818.7 sq mi) and one quarter of its fish species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
. Indonesia's coral reefs are located in the heart of the Coral Triangle
Coral Triangle
The Coral Triangle is a geographical term so named as it refers to a roughly triangular area of the tropical marine waters of Indonesia, Malaysia, Papua New Guinea, Philippines, Solomon Islands and Timor-Leste that contain at least 500 species of reef-building corals in each ecoregion...
and have fallen victim to destructive fishing, tourism and bleaching. Data from 414 reef monitoring stations in 2000 found that only 6% are in excellent condition, while 24% are in good condition, and approximately 70% are in poor to fair condition.
Philippines
In 2007, Reef CheckReef Check
Reef Check is an international non-governmental organization dedicated to the conservation of two reef ecosystems: tropical coral reefs and Californian rocky reefs. The Foundation is headquartered in Los Angeles, California, United States, but uses data from volunteer scuba diver teams in over 80...
, the world's largest reef conservation
Habitat conservation
Habitat conservation is a land management practice that seeks to conserve, protect and restore, habitat areas for wild plants and animals, especially conservation reliant species, and prevent their extinction, fragmentation or reduction in range...
organization
Organization
An organization is a social group which distributes tasks for a collective goal. The word itself is derived from the Greek word organon, itself derived from the better-known word ergon - as we know `organ` - and it means a compartment for a particular job.There are a variety of legal types of...
, stated that only 5% of Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
27000 square kilometres (10,424.8 sq mi) of coral reef are in "excellent condition": Tubbataha Reef
Tubbataha Reef
Tubbataha Reef is an atoll coral reef located in the Sulu Sea of the Philippines. It is a marine sanctuary protected as Tubbataha Reef National Marine Park...
, Marine Park
Marine Park
Marine Park is a neighborhood located in the New York City borough of Brooklyn, that lies between Mill Basin and Gerritsen Beach. The neighborhood is mostly squared off in area by Gerritsen Avenue, Flatbush Avenue, Avenue U and Kings Highway. It partly surrounds the eponymous park. The neighborhood...
in Palawan
Palawan
Palawan is an island province of the Philippines located in the MIMAROPA region or Region 4. Its capital is Puerto Princesa City, and it is the largest province in the country in terms of total area of jurisdiction. The islands of Palawan stretch from Mindoro in the northeast to Borneo in the...
, Apo Island
Apo Island
Apo Island is a volcanic island covering 12 hectares in land area, 7 kilometers off the southeastern tip of Negros Island and 30 kilometers south of the Negros Oriental capital of Dumaguete City in the Philippines....
in Negros Oriental
Negros Oriental
Negros Oriental is a province of the Philippines located in the Central Visayas region. It occupies the south-eastern half of the island of Negros, with Negros Occidental comprising the north-western half. It also includes Apo Island — a popular dive site for both local and foreign tourists...
, Apo Reef
Apo Reef
Apo Reef is a series of coral reefs encompassing 34 square kilometers within the waters of Occidental Mindoro in the Philippines. It is the world's second-largest contiguous coral reef system and the largest in the country...
in Puerto Galera, Mindoro
Mindoro
Mindoro is the seventh-largest island in the Philippines. It is located off the coast of Luzon, and northeast of Palawan. The southern coast of Mindoro forms the northeastern extremum of the Sulu Sea.-History:...
, and Verde Island
Verde Island
This article refers to an island, for the body of water see Verde Island Passage.Verde Island is situated along the bodies of Verde Island Passage between the islands of Luzon and Mindoro, Philippines. It was on 1988 when a small village was created through the effort of an European project using...
Passage off Batangas
Batangas
Batangas is a first class province of the Philippines located on the southwestern part of Luzon in the CALABARZON region. Its capital is Batangas City and it is bordered by the provinces of Cavite and Laguna to the north and Quezon to the east. Across the Verde Island Passages to the south is the...
. Philippine coral reefs is Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
's second largest.
Taiwan
Coral reefs in TaiwanTaiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
are being threatened by human population growth. Many corals are affected by untreated sewage and souvenir-hunting tourists, not knowing that this practice destroys habitat and causes disease. Many corals have turned black from disease off Taiwan's southeast coast.
Further reading
- Barber, Charles V. and Vaughan R. Pratt. 1998. Poison and Profit: Cyanide Fishing in the Indo-Pacific. Environment, Heldref PublicationsHeldref PublicationsHeldref Publications was the publishing division of the Helen Dwight Reid Education Foundation, a nonprofit educational organization. Professor Helen Dwight Reid, a political scientist who taught at Bryn Mawr College and the State University of New York at Buffalo, established the foundation in 1956...
. - Martin, Glen. 2002. "The depths of destruction Dynamite fishing ravages Philippines' precious coral reefs". San Francisco ChronicleSan Francisco Chroniclethumb|right|upright|The Chronicle Building following the [[1906 San Francisco earthquake|1906 earthquake]] and fireThe San Francisco Chronicle is a newspaper serving primarily the San Francisco Bay Area of the U.S. state of California, but distributed throughout Northern and Central California,...
, 30 May 2002