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Various corals in Chagos, 1999. A: A massive Lobophyllia corymbosa coral from Diego Garcia lagoon. Red disks are still-living polyps. B: A massive<br />
faviid coral, now unidentifiable. Dead part has eroded about 1 cm. C: Close up of edge of a table coral, showing eroding and crumbling tips. D: Large<br />
whorls of Echinopora lamellosa, mainly dead, but with some live tips to some of the leaves. Photos: C. Sheppard.<br />
A<br />
B<br />
C<br />
D<br />
6. Recovery<br />
There is little information on how long it may take for<br />
reefs to recover, but reef recovery on a much smaller<br />
scale clearly takes many years or centuries. The suggestion<br />
that this is a “natural event’’ merely dodges the<br />
issue, and may only provide a refuge in which to avoid<br />
finding a solution. It might be true that it has happened<br />
before – a century ago no reef monitoring took place<br />
anyway – but many of the coral colonies that were killed<br />
are around 200–300 years old. So clearly, this scale of<br />
mortality has not occurred within that time frame.<br />
7. Alternative stable states<br />
Several examples show that if a reef is stressed and<br />
changed, and the stress is removed, the reef may not<br />
necessarily revert to its original condition. In part, this<br />
appears to depend on the severity of the stress. Good<br />
examples of this exist in the Caribbean and Indian<br />
Ocean. When corals die, they form fragments which are<br />
abrasive and inhibit new coral settlement and growth,<br />
exacerbating the situation. The long-term prognosis of<br />
the 1998 coral mortality may therefore be very poor.<br />
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