Dissard Delphine auteur aut IRD Reichart G. J. auteur aut IRD Menkès Christophe auteur aut IRD Mangeas Morgan auteur aut IRD Frickenhaus S. auteur aut IRD Bijma J. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Over the last decades, sea surface temperature (SST) reconstructions based on the Mg/Ca of foraminiferal calcite have frequently been used in combination with the delta O-18 signal from the same material to provide estimates of the delta O-18 of water delta O-18, a proxy for global ice volume and sea surface salinity (SSS). However, because of error propagation from one step to the next, better calibrations are required to increase the accuracy and robustness of existing isotope and element to temperature proxy relationships. Towards that goal, we determined Mg/Ca, Sr/Ca and the oxygen isotopic composition of Trilobatus sacculifer (previously referenced as Globigerinoides sacculifer) collected from surface waters (0-10 m) along a north-south transect in the eastern basin of the tropical and subtropical Atlantic Ocean. We established a new paleotemperature calibration based on Mg/Ca and on the combination of Mg/Ca and Sr/Ca. Subsequently, a sensitivity analysis was performed in which one, two or three different equations were considered. Results indicate that foraminiferal Mg/Ca allows for an accurate reconstruction of surface water temperature. Combining equations, delta O-18 can be reconstructed with a precision of about +/- 0.5 parts per thousand. However, the best possible salinity reconstruction based on locally calibrated equations only allowed for a reconstruction with an uncertainty of +/- 2.49. This was confirmed by a Monte Carlo simulation, applied to test successive reconstructions in an "ideal case" in which explanatory variables are known. This simulation shows that from a purely statistical point of view, successive reconstructions involving Mg/Ca and delta O-18 preclude salinity reconstructions with a precision better than +/- 1.69 and hardly better than +/- 2.65 due to error propagation. Nevertheless, a direct linear fit to reconstruct salinity based on the same measured variables (Mg/Ca and delta O-18(c)) was established. This direct reconstruction of salinity led to a much better estimation of salinity (+/- 0.26) than the successive reconstructions. specialized ATLANTIQUE ZONE TROPICALE 032 034 18 2 423-439 2021 1726-4170 https://www.documentation.ird.fr/hor/fdi:010080932 10.5194/bg-18-423-2021 1726-4170 [F B010080932] https://www.documentation.ird.fr/hor/fdi:010080932 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers21-03/010080932.pdf IRD - Base Horizon / Pleins textes 2021-04-01 2025-02-24 fdi:010080932 fre