Coral Reefs

Mind Map by , created over 6 years ago

A-Levels Geography (Ecosystems) Mind Map on Coral Reefs, created by catherine.ellenj on 05/29/2013.

Created by catherine.ellenj over 6 years ago
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Coral Reefs
1 How is a coral reef formed?
1.1 What does a coral reef need to survive
1.1.1 Corals must be exposed to a sufficient amount of sunlight. This confines most corals to shallow waters that are clean and clear.
1.1.2 in a zone extending from 30° N to 30° S of the equator.
1.1.3 optimum temperature for most coral reefs is 26–27 °C. few reefs exist in waters below 18 °C Reefs in the Persian Gulf have adapted to temperatures of 13 °C in winter and 38 °C in summer.
1.2 3 types of reef
1.2.1 Fringing reef Border shorelines of continents and islands in tropical seas. Commonly found in the South Pacific Hawaiian Islands, and parts of the Caribbean.
1.2.2 Barrier Reef occurs farther offshore. Form when land masses sink, and fringing reefs become separated from shorelines by wide channels. Land masses sink as a result of erosion and shifting crustal plates of the earth. (Crustal plates lift or sink the seafloor and adjacent land masses.) Common in the Caribbean and Indo-Pacific. The Great Barrier Reef off northern Australia in the Indo-Pacific is the largest barrier reef in the world. This reef stretches more than 1,240 miles (2,000 km).
1.2.3 The Atoll If the land mass is a small island, it may eventually disappear below the ocean surface, and the reef becomes an atoll. Atolls are reefs that surround a central lagoon. The result is several low coral islands around a lagoon. Atolls commonly occur in the Indo- Pacific. The largest atoll, named Kwajalein, surrounds a lagoon over 60 miles (97 km) long.
1.3 Coral reefs are one of the most biologically diverse ecosystems on earth.
1.3.1 Contain a quarter of all marine life on the planet Indonesia has the greatest variety of fish though
2 Threats to a coral reef
2.1 Physical
2.1.1 Climate change/Global warming There is a chance that bleached coral can recover if conditions return to normal quickly enough. However, in the face of other human-induced pressures, corals have become vulnerable. In many cases, bleached coral colonies die Increases water temperatures can cause coral bleaching (when coral polyps expel the algae that live within them) The algae (zooxanthellae) provide the coral with up to 80% of its energy making it essential for its survival Algae usually provides colour to the coral so when they are expelled, the coral appears white or bleached. Coral and algae have a symbiotic relationship
2.1.2 Extreme weather waves easily break off or flatten large portions of coral reefs increased ­temperatures, altered salinity and increased rainfall are all stressors -- lengthy periods of cold rainy weather tend to suppress coral growth
2.1.3 Animals Crown-of-Thorns Starfish Found particularly Australia's Great Barrier Reef. Voracious predators that release the contents of their stomach on to the coral. Digestive juices then liquify the coral ready for consumption. A single individual can wipe out large areas in this way. They are almost completely covered in protective venomous spines capable of causing great pain in humans.
2.1.4 Disease Black band disease only coral disease that can be treated caused by cyanobacteria which manifests itself as a black band over corals surface
2.2 Human
2.2.1 Careless tourism Tourist resorts emptying sewage directly into water contributes to coral reef degredation Careless boating/diving/snorkeling When people grab/kick/walk on/stir up sediment they contribute to destruction Coral is also harmed or killed when people drop anchors on them or when people collect coral
2.2.2 Overfishing/destructive fishing practices Affects the ecological balance of coral reef communities destroys reefs and habitats via dynamite/blast fishing, cyanide fishing
2.2.3 Pollution Pollutants such as oil, animal waste and fertilizer increase the level of nitrogen in the water which causes an overgrowth of algae. This smothers the reef and cuts off their sunlight - EUTROPHICATION Litter can kill coral reef animals! Floating dustbin lids block sunlight that polyps need to survive Turtles mistake plastic bags for jellyfish and eat them. Plastic blocks digestive tract and causes them to starve to death Fishing nets can snag on reefs and strangle thousands of fish, sea turtles and marine animals. (MAIN REASON FOR DESTRUCTION IN THE MALDIVES)
2.2.4 Coastal development Increase in population = pressure on resources In many areas, developers build directly on top of coral reefs
2.3 Around one quarter of coral reefs worldwide are considered damaged beyond repair, with another two thirds under serious threat!
3 Sustainable Management/Development


3.1 Ecotourism is also being developed in many reef areas popular with tourists. This, in turn, will lead to increased global awareness
3.1.1 ECOTOURISM - “responsible travel to natural areas that conserves the environment and improves the well-being of local people"
3.1.2 Better development of tourist areas is needed to control increased runoff and ensure sanitation and power station facilities are not affecting the reef in an adverse way. Regulated development which follows a risk assessment in terms of damage to the reef Raising awareness in the area about how development can alter the reef ecosystem Increasing awareness around the world about the impacts of tourism on reef areas.
3.2 Zoning systems has been proposed, and areas have been created where any destruction of coral is prohibited, where tourist activities are allowed within guidelines and restrictions, and where there are only guidelines on habitat protection.
3.3 "developing an environment using methods/techniques which ensure that biodiversity is maintained"
3.4 Balance must be found between how much is used/take and how much is replensihed
3.5 Education/awareness
3.5.1 Needed if coral reefs are to survive. People need to be aware of the link between reef conservation and informed consumer purchases. Low public appreciation of the value of coral reefs as a resource (both commercial and ecological) has proved a continual problem, especially in places where tourism has rapidly increased over the past twenty years. Locals must also be educated about any management plans, and if possible the importance of coral reefs should be taught in schools
3.6 Fishing
3.6.1 both limit and prevent damage to fish populations via destructive and illegal fishing practices. Fish are reared purely for food and trade would mean a regulated amount of fish would be removed from the reef, leaving others to breed and the fish populations to rise again. Fish quotas, legal fish sizes and time and space restrictions on fishing could also help to ease the over fishing problem providing local communities with alternative means of income
4 Case Study
4.1 Great Barrier Reef, Australia (MEDC)
4.1.1 The day-to-day management of the Barrier Reef Marine Park is monitored by the Queensland Parks and Wildlife Service and the Great Barrier Reef Marine Park Authority, who are jointly responsible for ensuring the protection of this World Heritage Area. Management and protection of the Reef is also achieved through partnerships with the Queensland Boating and Fisheries Patrol, Queensland Water Police, Coastwatch and the Australian Maritime Safety Authority. The management of the area falls into four categories: Resource protection programs, Visitor education and services, Park monitoring and Surveillance and enforcement. Conservation is split into three main focus areas: the
4.1.2 Eastern coast of Australia
4.1.3 Largest reef in the world - can be seen from outer space
4.1.4 Over 2900 reefs from over 360 species of coral
4.1.5 Ecosystem is one of the most bio-diverse in the world
4.1.6 Tourism here creates US$5.5bn a year
4.1.7 Contains over 1500 species of fish, the world’s largest green turtle breeding area and important seabird breeding islands
4.2 Maldives (LEDC)
4.2.1 The Maldives is a cluster of around 1200 islands located in the Indian Ocean. Two hundred of those islands are home to the country’s 260,000 people, many of whom rely on the revenue from its reefs to survive. At present, the Maldives has a growing economy, and steadily improving living standards. However, there are several issues which the Maldives must address in order to preserve its reefs and ensure this success continues. For example, scientists have predicted a 0.5 metre sea level increase during the 21st century, which could upset the delicate reef ecosystem and potentially submerge the entire country. The country needs to assess its methods for protecting the marine environment, and encourage a sustainable and environmentally friendly approach to fishing. Tourism also needs to be managed, especially as it accounts for 19 per cent of GDP and one fifth of all employment in the country. The main attraction for tourists are the reefs, which need to be protected from the i

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