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Coral Microatolls From The Central Pacific Record Late Holocene El Nino, Colin Woodroffe, Michael K. Gagan

Faculty of Science, Medicine and Health - Papers: part A

Microatolls are discoid corals that have grown laterally because vertical growth is constrained by exposure at lowest tides. We demonstrate that a modern reef-flat Porites microatoll from Christmas (Kiritimati) Island preserves an oxygen isotope record of substantial sea surface temperature variations related to El Niño-Southern Oscillation (ENSO). We also show that a late Holocene fossil microatoll from the centre of the island contains interannual oxygen isotope variations over an approximate 20-year period. Three pronounced negative isotope anomalies attributed to warm El Niño events are superimposed on an annual cycle. El Niño events similar to those seen in recent decades appear …