Thermal and Non‐Thermal Controls on Benthic Foraminiferal Mg/Ca, Sr/Ca, B/Ca, and Mg/Li: Global Core‐Top Compilation, Revised Calibrations, and Application to the Geologic Record

Abstract Benthic foraminiferal Mg/Ca, Sr/Ca, B/Ca, and Mg/Li data are used to reconstruct deep‐sea temperature and seawater carbonate chemistry. However, the concurrent influence of various environmental parameters on these proxies is not fully understood. Here, we compile published and unpublished element/Ca core‐top data from Cibicidoides mundulus , C. pachyderma, Lobatula wuellerstorfi , Oridorsalis umbonatus , Nuttallides umbonifera , and Uvigerina spp. to determine the sensitivity of these species' Mg/Ca, Sr/Ca, B/Ca, and Mg/Li to temperature, calcite saturation state (Ω calcite ), dissolved inorganic carbon (DIC), and salinity. By applying multivariate linear regression analysis, we disentangle the effects of these environmental parameters on these species element/Ca. Based on this, we provide multivariate element/Ca calibrations with temperature and Ω calcite sensitivities for all species‐elemental system combinations. Overall, our analysis reveals that: (a) the Mg/Ca‐sensitivity to temperature is substantially lower compared to most previous approaches when accounting for the effect of Ω calcite ; (b) Sr/Ca is driven dominantly by Ω calcite ; (c) B/Ca can be linearly related to Ω calcite ; and (d) Mg/Li‐temperature calibrations have substantially lower degrees of unexplained variance compared to Mg/Ca. Our calibrations offer a statistically robust approach that also allows us to quantify the uncertainties in the reconstruction of temperature and carbonate chemistry when these element/Ca proxies are used. Finally, we present user‐friendly data processing software (“ElCaRBenthic”) that can simultaneously solve up to two benthic foraminiferal element/Ca data sets for temperature and Ω calcite (e.g., Mg/Ca and Sr/Ca), while providing the ability to correct for long‐term changes in seawater elemental chemistry and propagating all sources of uncertainty.