Management of Coral Reefs (DP IB Geography)

Revision Note

Coral reef Characteristics

Characteristics of coral reefs 

  • Coral reefs are productive environments

  • Warm coral reefs are located in tropical and subtropical waters (above 18°C)

  • Cold tropical reefs are located in deep, dark waters (4–12°C)

  • Coral reefs are also fragile environments

  • Any slight change in a coral reef environment can have devastating effects 

  • Coral reefs form by small coral larvae (polyps) attaching themselves to rocks 

    • Polyps secrete calcium carbonate, creating a hard skeleton. Other polyps can then connect to this skeleton

    • Polyps can divide (clone) themselves. These clones connect, forming a large organism

    • These organisms connect further over time, forming large coral reefs

  • There are three differing structures of a coral reef:

    • Fringing reefs 

      • The most common form of coral reef

      • Exist close to coastlines, like a border

    • Barrier reefs

      • Barrier reefs also exist on coastlines, but a deep lagoon separates the shore and the reef

      • Can form as fringing reefs grow and connect with each other

      • Very rare forms of coral reef

    • Atoll reefs 

      • As a volcanic island sinks beneath sea level and a fringing reef encircles it, atoll reefs form

      • They are circular shaped, with a lagoon in the middle

      • Found in the middle of the ocean

Formation of three coral reef structures 

Diagram illustrating different coral reef types: fringing, barrier, and atoll, showing their relationship to volcanic islands and surrounding water.
Formation of three coral reef structures

Coral Reefs Uses & Value

Uses and value of coral reefs 

  • Coral reefs are valuable ecosystems

  • Stakeholders value and use coral reefs differently

  • Coral reefs are also dangerously under threat

  • All stakeholders must work together to reduce threats to coral reef environments

  • Coastal protection

    • Coral reefs reduce the impact of strong storm waves, helping to reduce the erosion of the coastline

    • They protect coastal landscapes (e.g. mangrove swamps) and local communities 

    • Coral reefs are valuable to local residents and environmentalists 

  • Resource use

    • Fish are abundant in coral reef environments. This provides food and livelihoods for local residents

    • Both commercial and subsistence fishing occur in coral reef environments

    • Coral reefs help to develop medicine. The biodiversity of reef systems provides treatments for diseases including cancer, asthma and other bacterial or viral diseases

    • Coral reefs are valuable to fishing industries and science development

  • Tourism and the economy

    • Coastal areas with coral reefs attract millions of tourists each year

    • Divers and beach lovers alike bring vital tourism to coastal areas

    • Coral reefs boost the economy by providing jobs and bringing tourism to the area

    • From accommodation to boat crews, income from tourism is important for coastal communities

    • Coral reefs are valuable to tourists and the tourist economy

  • Species habitat

    • Coral reefs are home to all types of species; they are incredibly biodiverse

    • From fish to mammals, coral reefs provide food, shelter and nursery for an estimated 25% of all marine life

    • Coral reefs are valuable to marine life and environmentalists

Threats

  • Development

    • Coastline development for commercial and non-commercial practices puts pressure on coral reefs

    • Activities like quarrying, dredging, boating practices and recreation can damage coral reefs 

  • Overfishing and harvesting 

    • Overfishing of coral reef environments can be disastrous for the food web

    • Coral reefs need fish to remove dangerous algae

    • Blast fishing can damage coral reefs’ structure

    • Harvesting coral reefs for the jewellery/souvenir industry can damage biodiversity and cause habitat destruction

  • Pollution

    • Increased sediment (from development, agriculture, deforestation etc.) can choke coral reefs

    • Coral reefs require very little nutrients to function. More nutrients enter the coral reef environment from fertilisers, sewage and animal waste 

    • Algae growth increases with higher nutrient densities and uses vital oxygen and blocks sunlight

    • More harmful bacteria also grow with higher nutrient densities

    • Diseases enter coral reef environments from sewage, storm runoff and industrial and agricultural runoff 

    • Rubbish and microplastics also damage coral reef ecosystems

  • Acidification and bleaching

    • Algae gives coral reefs their colour

    • As sea waters warm, coral reefs get rid of this algae, causing coral reefs to lose colour. 

      • This is coral bleaching

      • This exposes the calcium carbonate and leaves corals under stress

    • As carbon dioxide in the atmosphere rises, so too do carbon dioxide levels in the ocean 

      • Carbonic acid increases, resulting in ocean acidification 

Examiner Tips and Tricks

Think about which stakeholders would benefit from coral reefs. Why do environmentalists benefit? Why do local populations benefit?

Case Study: The Great Barrier Reef

The Great Barrier Reef, Australia 

  • The Great Barrier Reef is the largest coral reef environment in the world

  • Located in the northeast of Australia, along the coastline of Queensland

  • It is over 1250 miles long

Location of the Great Barrier Reef

Map of Australia showing key locations including Queensland, Canberra, and the Great Barrier Reef highlighted as a World Heritage Site along the northeast coast.
Location of the Great Barrier Reef

Threats

  • Climate change

    • Sea waters around the Great Barrier Reef are rising in temperature, resulting in coral bleaching

    • Fears of flooding and storm intensity are exacerbated by climate change

  • Runoff

    • Increased runoff from agriculture is a large issue

    • This increases nutrients, sediment and pesticides in the water

  • Development

    • Past, present and future development poses a threat to the reef

    • These are agriculture, mining, urbanisation, industrial development, port development, aquaculture and tourism development

  • Fishing and poaching

    • Overfishing

    • Illegal fishing

    • Incidental catch 

  • Scale 

    • The Great Barrier Reef is vast. It is difficult to find enough funding, resources and people to protect the area

  • Invasive species

    • Crown-of-thorns starfish

    • Lionfish

Management 

  • World Heritage Site and a Natural Wonder of the World – this provides lawful protection and global recognition 

  • Legislations

    • Created for The Great Barrier Reef area, Queensland, The Commonwealth, and the International level

  • Reef 2050 plan

    • Long-term plan for reef sustainability

    • Bringing together governments, local communities and industries

    • Assesses values and threats to the reef, guiding professionals to where management is most necessary

  • Education

    • Education and training is important for people like tour guides

    • Presentations on reef protection regularly show at the Marine Park Authority Office 

    • Regular research is carried out to assess management strategies and their effectiveness

    • Universities in Queensland offer courses for coral research

  • Tools 

    • Zoning plans

      • Guiding where activities and industry can and cannot take place 

      • Includes ‘No Take Zones’, ‘Scientific Research Zones’, ‘Green Zones’ for recreation, and ‘General Use Zones’

    • Permits most activities require a permit, e.g. tourism, infrastructure construction, boating 

    • Policies – environmental, scientific and tourist government policies are set in place

  • Balancing stakeholders

    • Tourism management

      • Balancing the importance of tourism while protecting the reef

      • Guidance on managing reef tourism 

      • Future plans for tourism to be ecological as well as respectful to the heritage of the area

    • Heritage management

      • Respecting Aboriginal ownership of land and knowledge of the area

      • Working with Aboriginals and Torres Strait Islanders to protect the reef together

      • Training, programs, mapping and action plans

    • Science management 

      • Using scientific evidence to guide management practices

  • Monitoring

    • Fluker posts involve tourists in monitoring strategies

    • Tourists use these posts to take pictures of the reef

    • Photos are transferred to a site for professionals to examine

    • Cost-benefit – this saves money and time for workers

  • Species protection and control

    • Some species have different levels of protection (international, national, state or local)

      • This means they have lawful protection 

    • Species are also separated into threatened, at-risk or iconic

    • Some species must be controlled due to their negative impact, such as crown-of-thorns starfish outbreaks

      • Professional divers inject starfish to kill them (without harming the environment) 

  • Reef restoration

    • Planting vegetation in canals to reduce sediment

    • Coral IVF – growing baby corals outside of the reef and replacing them back into degrading areas

    • Coral fragments – taking fragments and planting them elsewhere (underwater or onshore in tanks)

    • Cryopreservation – freezing tissue in nitrogen for future preservation, reducing the risks of species extinction 

    • Photogrammetry – monitoring the growth of the coral reef

  • Traditional management

    • Indigenous People are using traditional and modern tracking methods to track animals like turtles 

    • There is a priority for subsistence fishing, limiting overfishing

    • Some areas of the reef are taboo, increasing protection

    • Some areas of the reef belong to Indigenous Groups 

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