Imprints of Atlantic Multidecadal Oscillation on pantropical seawater pH inferred from coral δ11B records

Understanding natural variability in seawater pH (pHsw) is crucial for predicting future ocean acidification. Coral boron isotopes (δ11B) offer an alternative method to extend pHsw records back centuries, shedding light on how pHsw varies over time. This study compiles both new and existing coral δ11B records from pantropical oceans to investigate multidecadal pHsw variability and its connection to climate variability. A notable finding is the pronounced influence of the Atlantic Multidecadal Oscillation (AMO) on pantropical coral δ11B-pH variations. This is primarily interpreted as the effects of AMO-associated climate changes on reef pHsw, rather than influencing coral physiological processes related to calcifying fluid pH. Key factors like wind speeds and hydrological variability related to Intertropical Convergence Zone (ITCZ) shifts are identified as potential drivers of the AMO's impact on pHsw. This study thus provides valuable insights into the broader effects of the Atlantic climate on pantropical seawater CO2 system. •The climate control on coral δ 11B records is revisited.•Most pantropical coral δ11B-pH records display AMO-like multidecadal variations.•Surface wind speeds and ITCZ-related hydrology may link the AMO to reef pHsw.