Australia's Great Barrier REEF.Coral reefs coral reefs, limestone formations produced by living organisms, found in shallow, tropical marine waters. In most reefs, the predominant organisms are stony corals, colonial cnidarians that secrete an exoskeleton of calcium carbonate (limestone). are the "rainforests of the sea"--the second richest ecosystem, or interdependent environment, on Earth after tropical forests. Reefs are made up of billions of tiny animals called coral polyps Polyps A tumor with a small flap that attaches itself to the wall of various vascular organs such as the nose, uterus and rectum. Polyps bleed easily, and if they are suspected to be cancerous they should be surgically removed. . The Great Barrier Reef Great Barrier Reef, largest complex of coral reef in the world, c.1,250 mi (2,000 km) long, in the Coral Sea, forming a natural breakwater for the coast of Queensland, NE Australia. off Australia's northeast coast is the world's longest coral reef coral reef Ridge or hummock formed in shallow ocean areas from the external skeletons of corals. The skeleton consists of calcium carbonate (CaCO3), or limestone. A coral reef may grow into a permanent coral island, or it may take one of four principal forms. chain and the largest single structure ever created by living creatures--so huge it's visible from space. Yet the Great Reef remains largely unexplored by marine biologists, scientists who study sea life. Like all reefs, it provides food, shelter, and protection for thousands of ocean plants and Animals Plants and Animals are a Canadian indie-rock band from Montreal, comprised of guitarist-vocalists Warren Spicer and Nic Basque, and drummer-vocalist Matthew Woodley.[1] They are signed to Secret City Records. . But coral reefs are in grave peril, explains David Gilliam, a research scientist at Florida's National Coral Reef Institute. Last year, 10 percent of the world's coral reefs died from water temperatures rising as a result of global warming global warming, the gradual increase of the temperature of the earth's lower atmosphere as a result of the increase in greenhouse gases since the Industrial Revolution. , Earth's heating temperatures due to increased trapped gases in the atmosphere. "Without protection, nearly three quarters of the world's reefs could die within 50 years," says Gilliam. REEF FACTS Great Barrier Reef Length: 2,027 km (1,260 ml) Width: up to 150 km (93 ml) Fish Species: over 1,400 Total Marine Species (such as eels and octopuses): over 2,000 Estimated Coral Species: about 400 Reefs in Danger: up to 60% World Reefs * cover 0.2% of the ocean floor and less than 0.1% (580,000 sq km) of Earth's surface * support 2,500 species of coral * consist of two types of coral: hard (reef-building) coral and soft coral * can be between 5,000 and 10,000 years old * contain about 25% of the world's ocean species, including 5,000 species of reef fish * serve as nurseries for growing fish * supply a source of protein (seafood) in human diets * provide food, shelter, and protection to many marine species How the Reef Formed Scientists believe the Great Barrier Reef formed 30 million years ago during an ice age, when frozen polar ice caps kept Pacific Ocean water levels much lower than today. Colonies of corals grew upward and outward from the Australian continental shelf, the land that slopes into the sea. Barrier reefs are separated from land by wide deep lagoons. The Great Barrier Reef acts as a sturdy wall that protects Australia's coastline against crashing Pacific Ocean waves. Coral Bleaching Coral grows only in clear tropical waters between 20 [degrees] and 28 [degrees] C (68 [degrees] to 82 [degrees] F). Earth's warming ocean temperatures cause coral bleaching. How? Coral polyps share their protective limestone shell with a type of alga (plant, usually aquatic, without stems, roots, or leaves). Coral provides the algae algae (ăl`jē) [plural of Lat. alga=seaweed], a large and diverse group of primarily aquatic plantlike organisms. These organisms were previously classified as a primitive subkingdom of the plant kingdom, the thallophytes (plants that with a home; in turn, algae supplement the coral's diet with needed sugars. When warm water stresses coral, polyps expel algae--which drains coral of color--and the polyps die, leaving behind only their skeletons. Tourist Damage Coral reefs are under attack from a host of sources. Tourists and scuba divers damage reefs by touching fragile coral, killing them. Pollution from sewage, industrial chemicals, and pesticides dumped into the ocean, suffocate suf·fo·cate v. 1. To impair the respiration of; asphyxiate. 2. To suffer from lack of oxygen; to be unable to breathe. suf living coral. 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. More precise biological and bioeconomic terms define 'acceptable level'. disrupts a reef's complex environmental balance Coral Life Coral polyps--some the size of your hand, others as tiny as a pinhead--collect the chemical calcium carbonate calcium carbonate, CaCO3, white chemical compound that is the most common nonsiliceous mineral. It occurs in two crystal forms: calcite, which is hexagonal, and aragonite, which is rhombohedral. (limestone) from seawater seawater Water that makes up the oceans and seas. Seawater is a complex mixture of 96.5% water, 2.5% salts, and small amounts of other substances. Much of the world's magnesium is recovered from seawater, as are large quantities of bromine. and secrete secrete /se·crete/ (se-kret´) to elaborate and release a secretion. se·crete v. To generate and separate a substance from cells or bodily fluids. it around their soft, tube-shaped bodies. The limestone hardens into a protective shell around each polyp polyp, in medicine, a benign tumor occurring in areas lined with mucous membrane such as the nose, gastrointestinal tract (especially the colon), and the uterus. Some polyps are pedunculated tumors, i.e. and cements it to the reef. As polyps die, a new generation "builds" atop their skeletons and the reef grows larger. Cross-Curricular Connection Geography: Locate the world's reef systems on a map. Where are most reefs located? Did You Know? * A report by Greenpeace, an environmental organization, estimates that most of the Great Barrier Reef will be dead in 30 years unless projected levels of climate change are mitigated. * Reef destruction is also caused by natural events such as hurricanes and outbreaks of predators, like sea stars and other coral-eating animals. * There are two additional types of reefs besides barrier reefs: Fringing reefs are submerged coral platforms that extend out from the shore. Atolls are rings of coral islands above the sea surface that surround a lagoon. National Science Education Standards The National Science Education Standards (NSES) are a set of guidelines for the science education in primary and secondary schools in the United States, as established by the National Research Council in 1996. Grades 5-8: structure and function in living systems * diversity and adaptation of organisms * population, resources, and environments Grades 9-12: interdependence of organisms * matter, energy, and organization in living systems * environmental quality * natural and human-induced hazards Resources The Great Barrier Reef--A Treasure in the Sea, by Alice Gilbreth, (Dillon Press, 1996) General information on coral reefs: www.terryparker.duval.k12.fl.us/reef.htm Reefs at Risk: coral.aoml.noaa.gov/ www.epa.gov/OWOW/oceans/coral/coralreef.gov/ Australia's Great Barrier Reef 1.e 2. d 3. a 4. b 5. c Australia's Great Barrier Reef Directions: Match the words in the left column with the correct phrase on the right. -- 1. coral bleaching a. type of plant -- 2. calcium carbonate b. interdependent environment -- 3. algae c. Earth's heating temperatures -- 4. ecosystem d. limestone -- 5. global warming e. caused by global warming |
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