Erosion vs. recovery of coral reefs after 1998 El Niño: Chagos reefs, Indian Ocean

Ambio. 2002 Feb;31(1):40-8.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Climate*
  • Cnidaria*
  • Ecosystem*
  • Environmental Monitoring
  • Fishes
  • Indian Ocean
  • Mortality
  • Population Dynamics
  • Temperature