Coral Reefs Flashcards
Temperature required for coral growth
23-25*C
depth for coral growth
less than 25m
why is clean, clear sediment free water required for coral growth?
light for photosynthesis
how is well oxygenated water maintained
steady, strong wave action
stable and steady ……? is needed for growth
salt content
what is the relationship between zooxanthella and coral?
food source - symbiotic relationship.
conditions for deep sea coral growth
- 4*C
- up to 6000m
- don’t need light.
characteristic of deep sea coral
grow very slowly
what is the carbonate compensation depth?
the point where deposition of CaCO3 = dissolution.
the boundary of maximum depth where CaCO3 is deposited.
why doesn’t CaCO3 deposit below CCD?
below CCD, water holds more CO2 as increased pressure.
so more carbonic acid - so CaCO3 dissolves faster.
effect of rising sea temp on coral reefs
- coral bleaching - expelling of photosynthetic algae
effect of rising sea level
if rises faster than coral can grow then coral drowns. CCD rises also.
effect of increased ocean acidity
raised CCD
more CO2 dissolves
stresses coral polyps
effect of land based pollution + raw sewage
- LICs - industrial + agricultural pollution reaches rivers + sea.
- raw sewage contains phosphates
growth of PHYTOPLANKTON. - increase in Crown of Thorns starfish - who eat plankton.
effect of shipping
- oil spills - Persian gulf
- plastic waste around ports - smothers + kills.
effect of overfishing
decreased biodiversity
effect of tourism
- walking on coral
- swimmers stir up sediment
- sand + limestone quarried for construction
- turbulence from boats
natural hazards effecting reefs
- tropical storms
- large waves
- Boxing Day tsunami 2004
interval between coral bleaching events have halved between what years?
1980-2016
what has halved between 1980 - 2016
the interval between coral bleaching events
effect of El Niño
- increased ocean temp.
- coral can’t regenerate if El Niño occurs too frequently.
