2What does it look like?A coral reef is made up of the shells of single, small marine animals called coral polyps. When coral polyps grow into a group they are called a coral colony. As polyps die, new ones grow on top of the old empty shells. Over time, the collection of shells left behind by dead coral polyps and dead coral colonies build large groups of rock-like structure called a coral reef. Although the entire coral reef looks like a lot of large rocks, the top surfaces are actually covered with new coral colonies that are very much alive.
3Cont.Fringing reefs lie near emergent land. They are fairly shallow, narrow and recently formed. They can be separated form the coast by a navigable channel.Barrier reefs are broader and lie farther away from the coast. They are separated from the coast by a stretch of water which can be up to several miles wide and several tens of metres deep.Atolls are large, ring-shaped reefs lying off the coast, with a lagoon in their middle. Atolls develop near the sea surface on underwater islands or on islands that sink, or subside.
4Animalsthere can be as many different types of fish in two acres of coral reef in Southeast Asia as there are species of birds on the entire continent of North Americasea urchins, sponges, sea stars, worms, fish, sharks, rays, lobster, shrimp, octopus, snails
5LocationCoral reefs are generally found in clear, tropical oceans. Coral reefs form in waters from the surface to about 150 feet deep because they need sunlight to survive. The three types of reefs include fringing reefs, barrier reefs, and atolls.
6TemperatureCorals live in areas where the temperature ranges between 25° and 29° Celsius (77° to 84° Fahrenheit). Because they are sensitive to changes in these conditions, corals are at risk of being damaged or destroyed.
7Plant and animal adaptations The recent increases in the frequency and intensity of conditions that contribute to bleaching (higher surface ocean temperatures, higher light intensities, and calmer water) may have outpaced the compensating mechanisms of many corals. We use the word adaptation in its more general sense, rather than in its strict evolutionary sense of genetic change in populations.We combine the more narrowly defined scientific usages of “adaptation,” “acclimation,” and “acclimatization” to make the usage relevant to the processes that may operate on decadal time scales of climate change.
8How are we affecting the Coral Reefs? Ten percent of the world's reefs have been completely destroyed. There are two different ways in which humans have contributed to the degradation of the Earth's coral reefs, indirectly and directly.Indirectly, we have destroyed their environment. coral reefs can live only within a certain temperature and salinity range. Global warming caused by the green house effect has raised the temperature of the oceans so high that the coral get sick and die.The direct way in which humans destroy coral reefs is by physically killing them. divers catch the fish that live in and around coral reefs. This would be OK if the divers caught the fish carefully with nets and didn't hurt the reefs or take too many fish. Often they blow up a coral reef with explosives and then catch all the stunned fish swimming around.
9Threats to the Coral Reef Natural EventsHurricanes, typhoons, El Niño, coral-eating organisms, and diseases are natural disasters coral reefs have been facing for millions of years.PollutionPollution adds all sorts of unnatural and potentially harmful substances to the reef system including nutrients, pathogens and trash. Pollution has been implicated in the apparent surge in coral diseases, especially in the Caribbean
10How can you help? Reduce, Reuse and Recycle. Save energy in your home by using compact fluorescent bulbs, energy efficient appliances, wrapping your water heater to save heat, run dishwashers and washing machines with full loads.Try to reduce fossil fuel emissions by driving less In your home: wherever possible, use least toxic household products such as * cleaning products-- look for non-petroleum-based surfactants, that are chlorine and phosphate free and that claim to be "non toxic" and biodegradable; * water based, low biocide, low VOC paints; * use compost to fertilize your garden and leave grass clipping on your lawn to reduce the need for fertilizers.