Coral Reefs PDF

CORAL REEFS OBJECTIVES ⚫ Describe the formation of coral reefs (fringing, barrier, atoll) ⚫ Identify the location of coral reefs in the Caribbean. ⚫ Outline the conditions necessary for successful coral reef formation. ⚫ Discuss the importance of coral reefs and the consequences of coral reef...

CORAL REEFS OBJECTIVES ⚫ Describe the formation of coral reefs (fringing, barrier, atoll) ⚫ Identify the location of coral reefs in the Caribbean. ⚫ Outline the conditions necessary for successful coral reef formation. ⚫ Discuss the importance of coral reefs and the consequences of coral reef destruction. ⚫ Suggest possible solutions for reducing coral reef destruction. 2 DEFINITION ⚫ A coral reef is a hard rocky ridge built up from the sea bed by many millions of tiny living coral animals called polyps. ⚫ It is their hard exoskeletons that form the reef itself. The ridge is composed mainly of calcium carbonate, formed by the secretions of small marine animals. 3 TYPES OF CORAL REEFS IN THE CARIBBEAN 4  FRINGING REEF ⚫ A shallow water feature found close to the and running parallel to the shore. ⚫ Forms from the gradual accumulation of coral close to the shore. ⚫ Over time, storms and marine erosion move the coral to form the shallow irregular coral platforms. ⚫ A shallow lagoon exists between the reef and the shore. 5 FRINGING REEF 6 DID YOU KNOW ???? ⚫ Most Caribbean coral reefs are of the fringing type, distinguished by the lack of a lagoon or backreef zone (or the presence of a very small one). These reefs tend to be extensive and well developed. ⚫ The fringing reefs encircle most of the islands throughout the Caribbean, some of which can be found in shallow waters thus providing great snorkeling and diving opportunities. ⚫ The largest and most beautiful can be found along the coast of Cuba, Jamaica, and part of the Bahamas. 7  BARRIER REEF ⚫ Larger than a fringing reef ⚫ Lies in deep water much further out to sea. ⚫ Develop where a fringing reef is formed next to a low-lying coastal plain. ⚫ Rise in sea level floods the coastal lowlands ⚫ Fringing reef continues to grow to form a barrier reef that is now separated from the coast by many kilometers of water. 8 BELIZE BARRIER REEF 9  CORAL ATOLL Is an isolated, almost circular ring-shaped reef rising out of deep water. A lagoon is found in the center. Often form at submarine seamounts (extinct volcanoes) where the rim of the crater creates the shallow water conditions necessary for coral growth. Initially, it forms a fringing reef, then barrier reef; finally when the island is completely submerged, the coral forms an atoll. Common in Pacific and Indian Ocean e.g.Maldives In the Caribbean, The Turneffe Islands, Glover’s Reef and Lighthouse Reef off the coast of Belize are atolls which were formed as coral grew around the former coastline of large islands which were submerged many thousands of years ago. 10 11 CORAL ATOLL 12 Why are coral reefs important? ⚫ A habitat for marine fish. ⚫ Commercial fishing grounds ⚫ Coastal protection - act as buffer zones ⚫ Raw material for beaches 13 Why are coral reefs important? Tourist attractions Coral ‘mining’ Medicinal purposes 14 Where are coral reefs found? FOUND MOSTLY IN THE TROPICS BETWEEN 30 ° N AND 30 ° S. 15 CORAL REEFS IN THE CARIBBEAN 16  What are the conditions necessary for coral reefs to grow? ⚫ Temperature – corals only live in seawater that has an average temperature of + 18 ° C. Ideal temp = 23 °C – 25 °C ⚫ Water depth - shallow water near coastlines ⚫ Presence of algae and fish – shallow water conditions allow for light to pass through so that algae can photosynthesize ⚫ Turbidity - clear, well-aerated water, unpolluted water ⚫ Salinity – corals thrive best in open sea away from freshwater found at river’s mouth. 17 WHAT ARE THE THREATS TO CORAL REEFS? ⚫ Global Warming – zooxanthallae are colorful creatures that co-exist with coral polyps. ⚫ Coral appears ‘bleached’ white when zooxanthallae and coral polyps die. 18 19 ⚫ Fishing ⚫ Tourism 20 WHAT ARE THE THREATS TO CORAL REEFS? ⚫ Sea urchins Plagues of starfish 21  WHAT ARE CONSEQUENCES OF CORAL REEF DESTRUCTION? ⚫ Decline in fish stock ⚫ Coastal erosion ⚫ Decline in tourism 22  MEASURES TO REDUCE CORAL REEF DESTRUCTION ⚫ Protected Areas ⚫ Reduce overfishing ⚫ Reduce pollution 23  CONCLUSION ⚫ Coral reefs are formed by coral polyps and other living creatures. ⚫ Coral polyps need warm, clean, shallow, well-aerated water with the right amount of salt. ⚫ Corals act as habitats, buffer zones and popular tourist destinations. ⚫ Fringing reefs are close to the shore while barrier reefs are further from the shore. ⚫ Coral reefs need to be protected against threats such as pollution, overfishing and tourism. 24