Multi-colony calibration of barium isotopes between shallow-water coral skeletons and in-situ seawater: Implications for paleo proxies

Barium incorporated in coral skeletons has been widely used as paleo proxies to study terrestrial inputs, upwelling and anthropogenic activities marine environments. However, these applications often face the challenges of poor replication skeletal Ba/Ca records from multiple colonies complex Ba sources coastal Recent studies isotopes seawater deep-sea corals have demonstrated potential trace water mixing ocean, but there is still a lack calibrations for shallow-water corals. In this study, we present first multi-colony isotope calibration three Porites lutea with contemporaneous in-situ data Singapore Strait. We also report regional masses around area (e.g. South China Sea, Malacca Strait Johor River estuary). concentrations compositions show strong influence following seasonal salinity monsoon-driven water-mass between Sea. The δ138/134Ba results are generally consistent time-series closely follow variations seawater. Despite partition coefficient having large uncertainty (DBa=0.91±0.29), fractionation relatively constant (Δ138/134Bacoral-sw=−0.28±0.06‰) shows no significant difference mechanism controlling incorporation remains unclear, evidence clearly indicates that originated dissolved offset allows reliable values. could be reconstruct surface variability Strait, reflecting monsoon driven changes mass mixing.