Scott,-P.J.B.; Risk,-M.J.; Carriquiry,-J.D. El Nino, bioerosion and the survival of East Pacific reefs. PROCEEDINGS-OF-THE-SIXTH-INTERNATIONAL-CORAL-REEF- SYMPOSIUM,-TOWNSVILLE,-AUSTRALIA,-8th-12th-AUGUST-1988.- VOLUME-2:-CONTRIBUTED-PAPERS-MINI-SYMPOSIUM-1-TO-10-14. Choat,-J.H.;Barnes,-D.;Borowitzka,-M.A.;Coll,- J.C.;Davies,-P.J.;Flood,-P.;et-al.-eds.. 1988. pp. 517- 520. An integrated study of the biology, ecology, geochemistry and sedimentology of the 1982-83 El Nino warming event in the East Pacific revealed that the magnitude and impact of this major hydrodynamic forcing function can be measured retroactively. El Nino is accurately recorded in the super(18)O/ super(16)O ratios of corals from Isla del Cano, Costa Rica, as well as in the reefal and offshore sediments. Analysis of its effect allows us to evaluate previous such events in other reef sequences, recent and fossil. The study also demonstrates that survival and recovery of the remnant reefs depend primarily on infaunal bioeroders.