Written by: Victoria Machin
Rivalling tropical forests of the Amazon or New Guinea, coral reefs are estimated to support a variety of life amounting to 25 percent of all marine life on the planet! (Coral Reefs). They form the nurseries for about a quarter of the ocean's fish. Coral reefs are immense structures formed by stony corals with limestone outer skeletons (Levy). The limestone is deposited primarily by coral polyp- a small, fragile tubular animal that secretes calcium carbonate to create a hard exoskeleton (Mother Jones and the Foundation for National Progress). The polyps reproduce thousands of times to build shapes of coral colonies depending on the species, wave action, currents, and sunlight in the area (Levy).
Reefs can be found all over the world-in the tropical and subtropical regions of both the Western Atlantic Ocean and all over the Indian and Pacific Oceans (Mother Jones and the Foundation for National Progress).
In recent years scientists discovered cold water coral reefs off the coast of Norway and deep underwater in the Mediterranean Sea (Coral Reefs). Generally, they are located at depths of less than 150 feet, in area's which are exposed to sunlight, salt water, and a temperatures of 68 to 92
degrees Fahrenheit. Coral reefs grow faster in clear water where light reaches the symbiotic algae, zooxanthellae, that live in the coral polyp's tissue (Mother Jones and the Foundation for National Progress). Wave action breaks down dead corals to fine sand and opens up areas to new growth. There is always a balance between destruction and growth on a coral reef (Hutchinson and Hawkins).
Coral Reefs support an extremely diverse and interconnected ecosystem. Thousands of animals live in and around reefs (Gray). Other animals visit coral reefs at certain times of the year. They are highly concentrated area's; however, they cover less than 1 percent of the entire marine environment (Levy). Common coral-reef animals include: sponges that provide shelter for tiny fish, crabs, and other small animals; sea anemones (close relatives of corals) which have a symbiotic relationship with clownfish and anemone fish; a variety of worms, including flatworms and polychetes; as well as sea stars, sea cucumbers, and sea urchins. A wide variety of schooling and solitary fish—including shark species—are also mainstays (Levy). The parrot fish has front teeth fused together to form a beak. It uses its beak to chew coral's limestone skeleton in order to eat its main source of food, algae. Though most organisms use or live in the water of the coral-reef, there are some that do not. Many birds live around the reefs for food supplies
and breeding for part of the year. Coral-reef birds include sea eagles, terns, albatrosses, and other seabirds (Levy).
Apart from helping to sustain a significant ecosystem within the ocean's water and source of biodiversity, coral reefs are of immense value to humankind. Latest estimates suggest coral reefs provide close to US$30 billion each year in goods and services, including
Coastal Protection: Sheltering land from harsh waves during storms, hurricanes, typhoons, and even tsunamis. The reefs save billions of dollars each by preventing coastal erosion, flooding and loss of property on the shore (Coral Reefs).
Natural Value: For many coastal societies around the world, coral reefs and their inhabitants are a part of cultural traditions.
Fisheries: If properly maintained, coral reefs can yield around 15 tonnes of fish and other seafood per square kilometre each year. An estimated one billion people depend on coral reefs for food and income; they are vital to the world's fisheries (Coral Reefs).
Tourism: Tourism revenues generated from coral reefs are extremely high in many places. The Florida Keys in the US generate at least US$3 billion dollars in income each year. Coastal communities in developing countries also use coral reefs as a significant or additional source of income (Coral Reefs). The beauty of coral reefs is appreciated by the people and without them the world would be very different (Coral Reefs).
Recently, scientists are expecting coral reef species to contribute to future medical advances. The Sherman team, along with William Gerwick of Scripps' Center for Marine Biotechnology and Biomedicine and the Skaggs School of Pharmacy and Pharmaceutical Sciences at UC San Diego, analyzed chemical compounds pulled from marine organisms living in coral reef sediments, blue-green algae, sponges and soft corals (Oceanography). They looked for substances, such as bacterial toxins, that can kill or disable cancer cells in the laboratory. Currently, more than a dozen such compounds from marine sources are in pre-clinical or clinical trials as cancer therapeutics. One such substance is curacin A, a candidate for an anti-cancer drug treatment first derived from a Caribbean coral reef cyanobacterium, L. majuscula, in 1994 by Gerwick's group (Oceanography). In the laboratory, curacin A effectively killed kidney, colon and breast cancer cell lines. Sherman and his colleagues latest finding is that the first links in the curacin-A chain include a member of the GNAT family of proteins, a group of enzymes that has long been known to play roles in gene regulation, hormone synthesis and antibiotic resistance (Oceanography). L. majuscula is a cyanobacterium, which are among the oldest organisms on Earth. Roughly 3 billion years ago, cyanobacteria began producing atmospheric oxygen that, much later, allowed more complex life forms to emerge. In the L. majuscula bacterium, the curacin A toxin likely performs a defence function, possibly protecting the microbe from predators (Oceanography).
Already coral reef organisms are being used in treatments for diseases like cancer and HIV (Coral Reefs). Just as with tropical forests, answers to medical problems in the coral reefs will continue - so long as they are kept healthy.
"Coral reefs have survived tens of thousands of years of natural change, but many of them may not be able to survive the havoc wrought by humankind (Coral Reefs)." Coral reefs provide many functions for people living in coastal communities, yet we are threatening their existence. Roughly one-quarter of all coral reefs worldwide are considered damaged beyond repair, while two-thirds are degraded and under serious threat (Coral Reefs).
Every year, large areas of reef are irreparably damaged by sewage and oil pollution, sedimentation, unsustainable fishing, and global warming which are all linked to an increase in coral bleaching (Hutchinson and Hawkins). The mortality associated with global change has a significant hindrance on the survival of coral reefs (Anup). Bleaching occurs when coral polyps, stressed by heat or radiation, expel the symbiotic algae—the zooxanthellae—that live in the reefs and provide the coral most of their food and oxygen. The zooxanthellae give them much of their colour, resulting in white patches over the colony. In some cases, there is a degree of recovery where new species of zooxanthellae become viable within the coral polyps (Hutchinson and Hawkins). However, it has also been found, however, that bleached colonies have a greater susceptibility to being broken apart by wave action (Hutchinson and Hawkins) (see figure 3).
For the last two decades, Indo-Pacific reefs have shrunk by 1 percent each year—a loss equivalent to nearly 600 square miles (1,553 square kilometres). That makes the rate of reef loss about twice the rate of tropical rain forest loss. Coral reefs are found in 109 countries; significant reef degradation has occurred in 93 (Anup). The decline of coral reefs was revealed to begin much earlier than assumed; in the late 1960`s (Scales).
The IUCN Red List of Threatened Species, highlights species that are extinct or extinct in the wild, critically endangered, endangered or vulnerable (Anup). Their spatial data shows the risks that coral reef species face around the world: (see figure 4)
The biggest of all coral reef structures, and the largest biological entity on the planet, is the Great Barrier Reef in Australia. This colossal coral reef stretches for more than 2000 kilometres along the north-eastern coast of Queensland (Hutchinson and Hawkins). It comprises of thousands of interlinked segments that are oldest and thickest at the northern end (Hutchinson and Hawkins). On April 3rd 2010, one of the Shen Neng 1, a bulk coal carrier's fuel tanks was damaged, running aground on the Great Barrier Reef carrying 975 tonnes of fuel oil and 65,000 tonnes of coal (Reytar). Reef conservationists and scientists worldwide gave a collective shudder. The area of the spill is a restricted area due to its environmental sensitivity. This horrible incident highlights the growing threat to coral reefs from human activities worldwide (Reytar).
27% of the world's coral reefs have already been lost. If present rates of destruction are allowed to continue, 60% of the world's coral reefs will be destroyed over the next 30 years (Coral Reefs). With all the damaging effects to coral reefs, it may be hard to be optimistic towards the future of these precise marine habitats. It may not be possible to completely reverse the large amount of degraded reefs, nevertheless, improvement is certainly possible. In 1998, there was an unprecedented bleaching while approximately16 percent of coral reefs were damaged, but about two-fifths of those recovered. If given the opportunity, then 50 percent of coral reefs in the world that aren't yet damaged beyond repair could, potentially, recover (Mother Jones and the Foundation for National Progress).
Two major groups working to protect and save the coral reefs are the Coral Reef Monitoring Network and Coral Reef Alliance (Anup). Groups like this provide the data and information needed to develop effective management plans and policies for reefs. Forming specific, detailed recommendations to national governments, local planning authorities, and marine park managers on how to counter threats to, and better manage, coral reefs in order to ensure their future place on Earth (Reytar). It is up to us to help these beautifully intricate structures survive.
Bibliography
Anup, Shah. "Coral Reefs." 13 February 2010. Global Issues. 18 April 2010
This article gives a variety of statistics, including images(stastistical) of coral reefs in recent years.
"Coral Reefs." 2010. WWF. 14 April 2010
This website has a large amount of information on coral reefs being faced with human activity.
Gray, Susan H. Coral Reefs. Minneapolis: Compass Points Books, 2001.
This book contained basic information on the ecology of coral reefs.
Hutchinson, Stephen and Lawrence E. Hawkins. Oceans: a visual guide. Ontario: Firefly Books, 2005.
This book contains a huge amount of information on marine biology; oceans. Specifically it contains a section on the risks imposing coral reefs including damaging effects like coral bleaching.
Levy, Janey. Discovering Coral Reefs. New York: Rosen Publishing Group, 2008 .
This book contains basic information on the ecology of coral reefs.
Mother Jones and the Foundation for National Progress. 2010. 15 April 2010
This article is a brief summary of al topics pertaining to coral reefs.
Oceanography, Scripps Institute Of. "Toxin From Coral-Reef Bacteria Could Become Next-Generation Cancer Drug." 29 November 2007. Science Daily. 19 April 2010
This article reveals coral reefs as being a future anti-cancer drug.
Reytar, Katie. "Great Barrier Reef Accident Highlights Risks to Reefs." 7 April 2010. World Resources Institute. 18 April 2010
This article gives information about the recent spill of the Shen Neng 1 in Australia.
Scales, Helen. "Coral Reefs Vanishing Faster Than Rain Forests." 7 August 2007. National Geographic. 18 April 2010
This article gives details upon the rate of coral reef decline and the answers to why it is declining.
Image Sources:
Figure's 1, 2, 3, 5
National Geographic Online Gallery
< http://ocean.nationalgeographic.com/ocean/photos/>
Figure 4
Anup, Shah. "Coral Reefs." 13 February 2010. Global Issues. 18 April 2010
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