14.4 Waves at Coral Reefs
b
5m
wave
direction
----.
o
T= JOOOy
- - T= 100y
contour h = 6 m
100
contour h = 6 m
-
D=2.0m
_._. D = 0.5 m
445
Fig. 14.16: Influence of sheltering effect on the probability of coral survival; a
distribution of wave height along reef circumference, b distribution of probability of
coral survival
The numerical simulations for various regions of the (GBR) showed that for
habitats exposed to cyclone induced waves, survival probability generally decreased with coral age and the rate of this decrease strongly depends on both
location and water depth (Massel and Done, 1993). For example, a coral in
9.0 m of water at Lizard Island (northern part of GBR) has about 70% chance
of reaching 30 years age, while the same coral in the Mackay (central part of
GBR) has only 20% chance (see Fig. 14.15).
Another important factor controlling the chance of survival for hard coral is
the location of coral on the reef slope with respect to the direction of incoming
waves. Coral on the exposed slope of the reef has a smaller chance of growing than coral located on the lee side of the reef. This effect is illustrated in