Question: Why save the reefs?
(Sarah) Ans: For the survival of reefs and to let the sea animals
have a place to live in. If the corals die, the sea animals
depending on the corals will die of starvation too. The earth is
currently losing species faster than any time in history due to
changes to the natural environment for the purpose of
development, agriculture, and industry. So we should protect the
coral.
(Tong Ying)Ans: Coral reefs protect the islands from natural disaster such as Tsunami and floods. They are also the main food
producer in the food chain, and once they are extinct, the food
chain will be broken and the sea animals depending on it will die.
We should do our part to save every coral to prevent them from
dying out.
Saturday, August 23, 2008
Saturday, August 16, 2008
Pictures of coral reefs
Healthy coralsBleached corals
Adapted from:
Thursday, August 14, 2008
Formations of coral reefs
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.
- 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.
- Table reef – an isolated reef, approaching an atoll type, but without a lagoon.
- Coral Atolls- rings of coral that grow on top of old, sunken volcanoes in the ocean. They begin as fringe reefs surrounding a volcanic island, then, as the volcano sinks, the reef continues to grow, and eventually only the reef remains.
Wednesday, August 13, 2008
How to protect coral reefs
AT HOME
- Help prevent water pollution by cutting down on your own use of herbicides, fertilizers, pesticides and cleaning products. Don't pour these down the drain.
AT PLAY
- Dispose of your rubbish properly. Don’t leave unwanted lines or nets in the water or on the beach. Any kind of litter pollutes the water and can harm the reef and the fish.
- Take only the fish you will eat that day. Leave tomorrow's catch in the water. Fishing pressure is one of the most serious threats to coral reef ecosystem and our island lifestyle.
- Never release aquarium or non-native plants or animals into waters. They can become vicious predators and/or carry disease that can kill reefs and fish.
- Stay off the reef when swimming, snorkeling and diving. One touch can harm it. More can kill it.
- Anchoring on the reef can kill it! Look for sandy bottom or use moorings if available.
Leave marine life alone. Enjoy nature but don't touch or chase animals.
Tuesday, August 12, 2008
Importance of coral reefs
- Coral reefs are important for many reasons. Most importantly, they provide protection and shelter for many different species of fish. Without coral reefs, these fish are left homeless with nowhere to live and have their babies.
- Not only do these fish increase the diversity of our world, but also reef fish and molluscs feed between 30 and 40 million people every year. They also make beautiful pets and the money made by catching and selling these animals provides many people with an income so that they can feed their families.
- And coral reefs are very important in controlling how much carbon dioxide is in the ocean water. Inside the sac of each coral polyp lives a one-celled algae called zooxanthellae (zoo-zan-thel-y). The algae gives off oxygen and other nutrients that the coral polyp needs to live and in return the polyp gives the algae carbon dioxide and other substances the algae needs. That is why coral reefs grow so near the surface of the water where it is the sunniest-the algae need sunshine for photosynthesis. Without coral, the amount of carbon dioxide in the water will rise dramatically and that would affect all living things on Earth.
- Coral reefs are very important because they protect coasts from strong currents and waves by slowing down the water before it gets to shore. That is why they are called barrier reefs. They provide a barrier between the ocean and the shore.
Coral Reefs
- The whimsical names of corals-bubble, staghorn, starburst and brain-hint at their spectacular appearance, but not necessarily at their true value. As the largest living structures on the planet, coral reefs are also among the greatest store houses of biodiversity on Earth.
- Coral Reefs are also one of the most threatened marine systems. Scientist estimated that unless we take immediate action, we could lose up to 70% of coral reefs by 2050.
Friday, August 1, 2008
Threats to coral reefs
- Land development and pollution
- Dynamite fishing
- Bleaching
- Ocean acidification
- Overfishing
- Pollution
- Storms
Land development and pollution
Extensive and poorly managed land development can threaten the survival of coral reefs. Within the last 20 years,once prolific mangrove forests,which absorb massive amounts of nutrients and sediment from runoff caused by farming and construction of roads, building, ports, channels, and harbors, are being destroyed. Nutrient-rich water causes fleshy algae and phytoplankton to thrive in coastal areas in suffocating amounts known as algal blooms. Both the loss of wetlands and mangrove habitats are considered to be significant factors affecting warer quality on inshore reefs.
Dynamite fishing
Many fishing practices harm the reef by physically damaging the reef or by killing non-targeted reef fish or other reef organisms. Blast fishing, a method of fishing in pars of the Caribbean, East Africa, and Southeast Asia, uses underwater explosions to damage the swim bladders of fish so that they float to the surface where they are easily captured. The blast of the explosions destroys coral and flattens the reef structure. In some places fishermen use cyanide to stun fish so that they can be captured alive. Small fish and coral polyps may be killed by the cyanide. A style of fishing called muro-ami involves scaring fish into a net by pounding on the reef with sticks or other heavy objects that severely damage the coral reef.
Bleaching
During the 1998 and 2004 El Nino weather phenomena, in which sea surface temperatures rose well above normal, many tropical coral reefs were bleached or killed. Some recovery has been noted in more remote locations, but global warming could negate some of this recovery in the future. High seas surface temperature (SSTs0) coupled with high irrandiance (light intensity), triggers the loss of zooxanthellae, a symbiotic algae, and its dinoflagellate pigmentation in corals causing coral bleaching.
Ocean acidification
The decreasing ocean surface pH is of increasing long-term concern for coral reefs. Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans. Carbon dioxide gas dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification.
Overfishing
In 1950 no fisheries were reported as being overexploited whereas by 1996 35% of fisheries were reporting overexploitation and an additional 25% were reported as being near overexploited. Overfishing can have a variety of negative effects on the environment. Overfishing can reduce genetic variation in a population making it harder for species to adapt to environmental change and mate. In addition, overfishing can alter tropic interactions and cause unexpected indirect effects on the environment. For example, in areas where predators have been removed increases in population size of their prey have resulted in unintended effect on the environment.
Pollution
Coral reefs can be damaged by a variety of pollutants that are produced by a variety of sources. Agricultural runoff can contain herbicides, pesticides, and nutrient fertilizers. Nirtogen and phosphorus addition can fertilize algae and result in algal blooms. Because algae can potentially grow so much faster than coral, they can out-compete corals.
Human sewage, often untreated, can add nutrients, microorganisms, and other pollutants to coral reefs. Nutrients in sewage can cause eutrophication. Bacteria added by sewage pollution are suspected causes of increased incidences of coral diseases such as white band disease.
Chemical pollution can also harm coral reefs. For example, oil spills, the result of spills from drilling or discharge of oil from vessels can harm reefs. They can be especially harmful if they occur during coral spawning because the oil can kill eggs and sperm.
Solid pollution such as plastics and discarded fishing nets (ghost nets) can also damage reefs.
Storms
Coral reefs can be damaged by natural events such as hurricanes, cyclones, and tsunamis. Wave activity can break apart corals; branching corals are more susceptible to storm damage than mound-building corals. Storms rarely kill all corals, and because storms are a natural part of coral reef ecosystems, coral species should be adapted to this type of disturbance and be able to recover following storms. However, human alteration to the environment may make recover more difficult. For example, the addition of nutrients or removal of herbivores might favor the growth of algae that is able to overgrow coral before they are able to recover.
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