Erosion vs. recovery of coral reefs after 1998 El Niño: Chagos reefs, Indian Ocean.
Three years after most corals died on the central Indian Ocean reefs of Chagos, erosion and recovery were studied to 30 m depth. Mortality was near-total to 15 m deep in northern atolls, and to > 35 m in central and southern atolls. Some reef surfaces have 'dropped' 1.5 m due to the loss of dense coral thickets. Coral bioerosion is substantial, reducing 3-D reef 'structure' and forming unconsolidated rubble. Juvenile corals are abundant, though mostly on eroding or unstable substrates, and are of less robust species. Reef fish abundance and diversity at 15 m depth remains high; species dependent on corals have diminished, while some herbivores and detritivores have increased. A new sea surface temperature (SST) data set shows that mean SST has risen 0.65 degree C since 1950. The critical SST causing the mortality in Chagos was 29.9 degrees C.
Sheppard
Charles R C
CR
Cambridge Coastal Research Unit, University of Cambridge, UK. csheppard@bio.warwick.ac.uk
Spalding
Mark
M
Bradshaw
Clare
C
Wilson
Simon
S
D000818:Animals; D002980:Climate; D003063:Cnidaria; D017753:Ecosystem; D004784:Environmental Monitoring; D005399:Fishes; D019156:Indian Ocean; D009026:Mortality; D011157:Population Dynamics; D013696:Temperature