Coral Reefs Flashcards
Main ecological features
Located around the equator
Shallow warm water - mid 20s
High light availability
Low nutrient water - slows algal growth
Consistent salinity
Low turbidity
What is a coral reef?
Made up of coral polyps
Polyps secret calcium carbonate
What species are coral polyps ?
Cnidarians
How do coral polyps feed and get the energy they need to survive?
Tentacles and cilia - trap small particles
Nematocysts - stinging cells to catch live prey
Symbiotic relationship with zooxanthellae (photosynthesising algae) - the algae provides coral with oxygen and sugars, coral provides algae with CO2, phosphorus, nitrogen and a protective habitat
Importance of coral reefs to humans
Provide food
Development of new medicines
Carbon sequestration
Cultural heritage
Protect mangroves and sea grass meadows
Provide jobs
Provide coastal protection for over 500 million people
Supports 25% of all marine species
Examples of medicines developed from coral reef species: coral
Used in bone grafts
Secosteroids - used to treat asthma, arthritis and other inflammatory diseases
Examples of medicines developed from coral reef species: Sea Sponge
Antiviral drugs
Treat HIV and AIDS
Examples of medicines developed from coral reef species: Indian Ocean Sea Hare
Dolastin 10
Cancer drug - inhibits cell division
Threats to coral reefs: Physical damage
Caused by; harmful fishing methods (e.g. bottom trawling), divers, coastal development
Intentional and unintentional (tourism)
Threats to coral reefs: Pollution
Litter
Oil spills
Sewage
Eutrophication
Threats to coral reefs: Introduced species
Escape from fish farms
Ballast water - transfers organisms from different oceans
Threats to coral reefs: Collection of ornaments and souvenirs
Intentional removal of coral
Made into jewellery
Reduced by CITES - reduced trade
Threats to coral reefs: Coral Bleaching
Caused by temperature change
Corals lose all colour - expel algae causing polyps to die
High turbidity
Threats to coral reefs: Coastal development
Encroach onto coral reefs
Increases pollution and turbidity
More frequent boat activity
Noise pollution
Threats to coral reefs: Sedimentation
Build of sediment caused by disturbing the sea bed
Increases turbidity - slows photosynthesis of algae
Runoff from coastal development
Threats to coral reefs: Fishing
Overfishing - fishing over maximum sustainable yield
Destructive fishing methods - bottom trawling, ghost fishing, dynamite fishing
Threats to coral reefs: Loss of interdependent habitats (sea grass meadows and mangroves)
Disrupts life cycles
Some species become extinct
Crown of Thorns Starfish Case Study
more fertile than any other invertebrates
smothers and dissolves the coral
usually kept in balance by pufferfish
agricultural runoff = more larvae survive = algae grows faster (main food source)
consume polyps = ecosystem collapses
controlled by improving water quality, physical removal and biological controls
How do MPAs protect coral reefs?
manage overfishing
support the control of threats
protected from all extractive and destructive uses
divers are educated
Example of MPA
Great Barrier Reef Marine Park
established 1975
designated zones for different uses (recreational/research)
How are fishing controls helping coral reefs?
ban on bottom trawling and dynamite fishing
no-take zones = stopped disturbances
minimum/maximum catch size
restrictions on net size
quotas
Example of a coral reef that is recovering due to fishing controls
Great Barrier Reef - no take zones
What damage has been caused by tourism on coral reef systems?
pollution from boats
wildlife disturbances
pieces of coral snapped off for souvenirs
increased stress causing coral bleaching
How are tourism activities being restricted to protect coral reefs?
maximum number of tourists that can visit a location
educating tourists on their importance
fixed moorings to stop ships dropping anchors
How can we continue to explore coral reef resources sustainably?
CITES
extract in low volumes
do not extract during breeding seasons
only allow small scale fishing
quotas
minimum/maximum catch size
Example of artificial reef creation
Rigs to Reef
use decommissioned oil rigs
use of concrete structures - as they have similar compositions as reefs
large surface area
