Tropical Coral Reefs Flashcards
Where are the corals found?
Towards the Indo-West pacific
20° isotherm
Warm shallow waters
What are the required conditions?
20°C waters
Clear
Shallow
Stable sea levels
What are reed building corals called?
Hermatypic corals
What are stromatolites?
The oldest recorded life
Produced by Cyanobacteria binding to sand particles
What are the features of coral reefs?
Biogenic - structures that grow Complex mosaic of hard and soft surfaces Micro/macro topography - high heterogeneity Ecological niches Oasis of biodiversity
What are the main types of reefs?
Fringe reefs
Barrier reefs
Atolls - no exposed landmass
Darwin’s hypotheses were that the grew around volcanoes
What are coral reefs?
Phylum - Cnidaria
A simple bag One opening Tentacles Radial symmetry Gastrovascular cavity Specialised stings Simple nervous system
What is the reef geological development like?
30-50 m of water
Coraline material extends down to 120-160 m
Reefs separated by erosion surfaces
Episodic growth
Current reefs have been growing for 8000 years (last ice age)
What is the reef building process?
Rocks made by interactions of living things
Agents
Fast growing
Cemented by coralline algae
What is zooxanthellae symbiosis?
Algae acquired through ingestion, species selected and maintained in polyp tissue
Provides 90% of the corals energy and enhances calcification
What is reef bleaching?
Stress causes algae to eject from the polyps
Reef becomes white
Can recover if zooxanthellae is re - absorbed
How do corals sexually reproduce?
Broadcast spawning
It maintains genetic variability and allows for adaptation
It is synchronised by water temperature and the moon cycle
Occurs at night
