New stable isotope results from a 173‐year coral from Espiritu Santo, Vanuatu

Abstract

Long coral records provide valuable information on pentadal‐decadal scale climate variability. Previously we have reported on a preliminary analysis of a 173‐year record (1806–1978) from the island of Espiritu Santo (Republic of Vanuatu). Although this record contained information in the pentadal‐decadal band, low sampling resolution raised questions about the validity of the results. Herein we report new data from the Santo record, in which the sampling resolution has been doubled and the validation database expanded. Variations in coral δ18O at Santo record the combined effects of variations in SST and rainfall‐induced salinity changes. The most prominent spectral peaks in the time series are at the annual cycle and 14–15 and 7.4 years. The robust occurrence of the 14–15 year peak provides additional support to the importance of this oscillation as a cause of decadal‐scale climate variability. Overall, our new results provide greater credibility to the conclusions raised in the earlier study and indicate that the Santo record can more confidently be incorporated into the still‐small network of multicentury coral records of climate change.