GBR

• Spatial patterns and dimensions

  Location, latitude, Extent (size & shape) and continuity
• Size

  • Length is 2300 km
  • 2900 reefs
  • 900 islands
  • Covers an area of 348 700 km2
• Shape

  • Fringing Reefs
  • Barrier Reefs
  • Atolls
  • Patch Reefs
  • Ribbon Reefs
• Extent


  • Length is 2300 km
  • 2900 reefs
  • 900 islands
  • Covers
  • Covers an area of 348 700 km2
• Atmosphere

  Temperature, Wind, Precipitation
• Temperature

  • Ideal: 27-32℃
  • Too low: Zooxanthellae cannot produce the limestone
  • Too hot: Zooxanthellae will leave the coral polyp (loose energy) = causing a bleaching event
• Wind

  • Aeolian erosion → shape indiv reefs
  • Influence wave formation & currents
  • Influence areas of coral growth
• Precipitation

  • Tropical location = extensive rain
  • Needs high salinity (salt)
  • Too much isn't good for coral growth: needs clear water free from chemicals & low turbidity to grow
  • Freshwater pools on top of coral (less dense than salt water)
• Earth Movements

  • Subsidence: Sinking of Earth's lithosphere, happened 2x, The rate of subsidence & sea level changes = determine reef growth over time
  • Hydro-isostasy: Type of subsidence, Lithosphere is depressed by the weight of the overlaying water/ ice & rises/springs up again when that weight is removed
  • Rifting: A place where the Earth's crust is being pulled apart = form valleys, Creates depth of water required for optimal coral growth
• Continental Drift


  Theory: continents of the Earth move gradually over a layer of liquid rock (molten rock) underneath the earth's surface, Allowed for the reefs to move to warmer waters = key optimal growth factor
• Weathering & Erosion

  • Chemical Weathering: Coral reef is made of CALCIUM CARBONATE -limestone, Coral surfaces are eroded by the Carbonic Acid in the rain = form rills & channels, Rainwater & carbon dioxide form rills and channels, Makes new substance
  • Mechanical Weathering: Location in ocean makes them subject to Large waves & strong winds, Break apart & move large areas of coral
  • Biological: Parrotfish physically break apart the coral & move them as they browse, Worm species tunnel through corals using acid secretions, weakening the structure
• Hydrosphere

  • Currents: Move sediment weathered & eroded from other areas to be deposited onto the reef to form islands, cays etc, Bring tiny organisms called zooplankton → help feed the variety of life, Determine water movements
  • Flow of Water: Millions of tiny air bubbles in waves that crash on the edge of reefs = provide oxygen for optimal coral growth, Powerful force of waves can break off & transport coral pieces, Grow best when there is high wave energy = creates more oxygen
• Biodiversity

  • Large biodiversity: 2000 fish species, 500 coral species
  • High degree of specialisation & endemic species
  • Contains every environmental relationship: symbiosis, parasitism, predation & competition
• Polyps


  Primitive organisms containing a digestive sac/stomach & an outer skeleton of limestone, Pulls food into mouth via tentacles, Symbiotic relationship: zooxanthellae lives in, Each reef begins with a single polyp which reproduces by itself to create a colony, Polyps die: limestone skeleton remains on which new corals form, Photosynthesises
• Invasion

  Crown-of-thorns Starfish Infestation: Predator → Feeds on living coral tissue, Stomach eversion: Pulls it stomach out through its mouth over coral polyps, Releases digestive juices onto coral, Attracts more starfish, Leaves a white coral skeleton, Caused large-scale coral destruction
• Succession

  Coral reefs are built up of old coral on top of each other → succession process: coral spawning, Primary Succession: Organisms invade, colonise, grow, Secondary Succession: Replace
• Optimal conditions for Coral Growth


  • Shallow water
  • Warm temp:
  • High Salinity & Oxygen levels
• Human impacts (positive and negative)


  Coral bleaching: Increase in sea temp, symbiotic relationship between coral polyp & zozo breaks down = expel algae = loose colour

  boats - oil spills & rubbish.

  Moorings & anchors destroy coral

  Water-based: snorkelling: divers swim to close to corals & break them
• Contemporary Management

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• Traditional Mangement


  • Totesim identifies a person or group with a plant or animal species
  • Diamond stingray (Yama) is the totem of the Wuthathi tribe
  • Prevented them from killing or eating their totem and sourced a variety of other food sources
  • Intragenerational equity was limited
  • Performed rites to ensure the continued proliferation of their totemic species,
  • 50 shark species that are still present today.
  • Sharks are a totem of the Meriam people from Murray Islands
• GBR Contemporary Management - Commerical Zones

  planned sustainable use of fishing & tourism activities

  • endanger species Largetooth Sawfish
  • Generating $6.4 billion tourism annually
  • 2004: 59,000 recreational vessels
  • Release petrol & oil spills --> contaminate water
• GBR Contemporary Management - Green Zones

  
  

  GBR Marine Park Authority: The Park Zoning Plan 

  Scientific zones, general zones, green zones and commercial zones. 

  The green zones: Green zones safeguard vulnerable species, enabling scientific research

  • fish species to grow without disruption, contributing to the substantial growth found in a study between 1983 and 2012 of the length, density and biomass of coral trout in zoned areas.