El Niño-Southern Oscillation: Effects on eastern Pacific coral reefs and associated biota
Glynn, P.W.; Mones, A.B.; Podestá, G.P.; Colbert, A.; Colgan, M.W. (2016). El Niño-Southern Oscillation: Effects on eastern Pacific coral reefs and associated biota, in: Glynn, P.W. et al. (2017). Coral reefs of the eastern tropical Pacific: Persistence and loss in a dynamic environment. Coral Reefs of the World, 8: pp. 251-290. https://dx.doi.org/10.1007/978-94-017-7499-4_8
In: Glynn, P.W.; Manzello, D.P.; Enochs, I.C. (Ed.) (2017). Coral reefs of the eastern tropical Pacific: Persistence and loss in a dynamic environment. Coral Reefs of the World, 8. Springer Science+Business Media: Dordrecht. ISBN 978-94-017-7498-7; e-ISBN 978-94-017-7499-4. xxv, 657 pp. https://dx.doi.org/10.1007/978-94-017-7499-4, more
In: Coral Reefs of the World. Springer: Dordrecht. ISSN 2213-719X, more
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Coral bleaching; Thermal thresholds; Bleaching indices; Galápagos |
| Authors | | Top |
- Glynn, P.W.
- Mones, A.B.
- Podestá, G.P.
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| Abstract |
The sudden and sporadic occurrence of anomalous conditions associated with El Niño-Southern Oscillation (ENSO) can precipitate diverse, immediate and long-term effects on eastern Pacific reef-building corals and associated organisms. ENSO is manifested in two complementary phases, namely warm (El Niño) and cool (La Niña) events, which have contrasting and potentially negative effects on coral reef ecosystems. Of the two distinct types of El Niño activity—Eastern-Pacific (EP) and Central-Pacific (CP)—the former exhibits maximum SST anomalies and related climate and weather impacts that affect eastern Pacific coral reefs. Relevant ENSO conditions, with direct or indirect effects, include (a) high and low sea temperature extremes, (b) thermocline and nutricline depths, (c) high and low sea level stands, (d) storm activity, (e) rainfall patterns (and terrestrial runoff), and (f) deviances in surface current direction, velocity and spatial extent. The first sign of ENSO stress to zooxanthellate corals is tissue blanching or bleaching, which may occur during periods of elevated (El Niño) or depressed (La Niña) thermal anomalies. Earlier studies of thermally induced coral bleaching in the Galápagos Islands and Panama are updated to 2012 with attention to anomalous warm and cool events that are stressful to reef-building corals. When thermal conditions normalize, surviving reef-building corals typically re-gain their usual complement of zooxanthellae (symbiotic dinoflagellates) and pigmentation. Long-term ecological effects from extreme ENSO activity, particularly during El Niño sea warming events, may occur over months or years following initial impacts. Such effects can markedly reduce coral cover, cause local species disappearances and significantly change the abundances of coral-associated taxa. The bioerosion of dead corals and carbonate frameworks can eliminate essential habitat space for a multitude of species if coral recruitment is suppressed and recovery unduly prolonged. Coral reef recovery and resiliency are examined in the context of recent ENSO disturbances. Since the last very strong 1997–98 El Niño coral reef bleaching event, live coral cover has increased significantly on many but not all equatorial eastern Pacific (EEP) reefs. |
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