Carbon Isotopic Fractionation of Alkenones and Gephyrocapsa Coccoliths Over the Late Quaternary (Marine Isotope Stages 12–9) Glacial-Interglacial Cycles at the Western Tropical Atlantic ...

• Main Authors: González-Lanchas, Alba, Hernández-Almeida, Iván, Flores, José A., Sierro, Francisco J., Guitián, José, Stoll, Heather M.
• Format: Text
• Language: English
• Published: ETH Zurich 2021
• Subjects: coccolithophores; alkenones; photosynthetic carbon isotopic fractionation; CO2; multiproxy; stable isotope vital effects; ice core
• Online Access: https://dx.doi.org/10.3929/ethz-b-000504118; http://hdl.handle.net/20.500.11850/504118

The sensitivity of coccolithophores to changing CO2 and its role modulating cellular photosynthetic carbon isotopic fractionation (εp) is crucial to understand the future adaptation of these organisms to higher CO2 world and to assess the reliability of εp for past CO2 estimation. Here, we present εp measured on natural fossil samples across the glacial-interglacial (G-I) CO2 variations of marine isotope stages 12 to 9 interval (454–334 ka) at the western tropical Atlantic Ocean Drilling Program Site 925 together with a set of organic and inorganic geochemical, micropaleontological and morphometrical data from Gephyrocapsa coccoliths in the same samples. The ∼2‰ variation in εp is significantly correlated with the CO2[aq] concentrations calculated from assumption of air-sea equilibrium with measured ice core pCO2 concentrations. The sensitivity of εp to CO2[aq] is similar to that derived from a multiple regression model of culture observations and is not well simulated with the classical purely diffusive ... : Paleoceanography and Paleoclimatology, 36 (8) ...