Bioclimate.org: A comparison of the 1998 and 2002 coral bleaching events on the Great Barrier Reef: spatial correlation, patterns, and predictions

(2004) A comparison of the 1998 and 2002 coral bleaching events on the Great Barrier Reef: spatial correlation, patterns, and predictions

Authors	Berkelmans R. , De'ath G. , Kininmouth S.
Source	Coral Reefs (78)
Type	P - Paper (2851)
Peer Review	2 - Medium (2288)
Audience	G - Generalist (1722)
Pages	74-83
Journal Number	23
Notes	Detailed mapping of coral bleaching events provides an opportunity to examine spatial patterns in bleaching over scales of 10 s to 1,000 s of km and the spatial correlation between sea surface temperature (SST) and bleaching. We present data for two large-scale (2,000 km) bleaching events on the Great Barrier Reef (GBR): one from 1998 and another from 2002, both mapped by aerial survey methods. We examined a wide range of satellite-derived SST variables to determine which one best correlated with the observed bleaching patterns. We found that the maximum SST occurring over any 3-day period (max3d) during the bleaching season predicted bleaching better than anomaly-based SST variables and that short averaging periods (3–6 days) predicted bleaching better than longer averaging periods. Short periods of high temperature are therefore highly stressful to corals and result in highly predictable bleaching patterns. Max3d SST predicted the presence/ absence of bleaching with an accuracy of 73.2%. Largescale (GBR-wide) spatial patterns of bleaching were similar between 1998 and 2002 with more inshore reefs bleached compared to offshore reefs. Spatial change in patterns of bleaching occurred at scales of 10s km, indicating that reefs bleach (or not) in spatial clusters, possibly due to local weather patterns, oceanographic conditions, or both.