Coral Bleaching - Most Severe Bleaching Event Recorded

The most severe mass bleaching event recorded took place in 1998. This coincided with a strong ENSO at the same time, which caused SSTs around the Pacific Ocean to rise by up to 0.9˚C (Goreau et al., 2000). For example, studies conducted on the effects in the West Pacific found that some areas of the inner and southern Great Barrier Reef were hit by 80-90% mortality rates as a result of bleaching (Goreau et al., 2000), far higher than any levels previously recorded. Again research shows that recovery is taking place however the timescale for a full recovery, or whether or not a full recovery is possible, is not known. However due to the extent of the bleaching, recruitment of new corals was limited in the short term as most source regions of corals were also badly damaged in the incident.

In order to gain a better biological understanding of bleaching, the process can be split into three subdivisions: triggers, mechanisms and symptoms. These will be considered below in more detail.