Investigation of sea surface temperature changes from replicated coral Sr/Ca variations in the eastern equatorial Pacific (Clipperton Atoll) since 1874
Abstract Sub-seasonally resolved and replicated coral Sr/Ca time series at Clipperton Atoll (10°18′N, 109°13′W) in the eastern Pacific are assessed as a sea surface temperature (SST) proxy in this region with small seasonal SST variability. The composite coral Sr/Ca time series is a partially replicated record of three live and one sub-modern colony of Porites lobata extending back to 1874. Large inter-colony coral Sr/Ca offsets equate to relative SST differences of 0.6 to 4.3 °C and limit the ability to reconstruct absolute SST changes. Moreover, the replication method revealed a 12-year section of growth in one colony where mean Sr/Ca was anomalously low (~ 1 °C higher SST) relative to the other colonies without evidence of diagenesis or other significant skeletal alterations. The presence of this anomalous interval supports the need for multi-coral Sr/Ca replication in specific sites or regions. The Clipperton Composite Sr/Ca anomaly record is significantly coherent (r = 0.71–0.76, p