Storms

Figure 6-Bird's eye view of a hurricane (Descloitres, 2003)

Although there have been no clear patterns in the frequency of storms recently, the IPCC (2007) predicted that tropical cyclones will become more intense and they will occur over a much larger region. Storms, including cyclones (Figure 6) can cause devastating damage to reefs on a local scale. Damage tends to be worse on the reef slope, which receives the full force of the waves (Scoffin, 1993). The severity of damage caused by the storm depends on the coral itself, factors such as age, species assemblages, skeletal strength, growth form and attachment strength affects the coral’s ability to withstand storms (Done, 1992).

Guillemot et al. (2010) studied the effect of cyclone Erica on a reef in New Caledonia. Straight after the storm coral cover decreased, the amount of rubble and algal cover greatly increased. However the midterm effects were worst, the average coral cover dropped even lower. Recovery of the reef did not begin until two years after the storm.

With storm frequency increasing coral morphology might show a phase shift towards corals with stronger skeletons, but these types of corals are slower growing so this will have an effect on the reef’s ability to cope with sea level rise (Knowlton, 2001). Storms will also reduce the resilience of corals meaning it will take a lesser event to cause permanent damage to the reef (Hughes et al., 2003).

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