Hydrographic control on carbon isotope fractionation in coccolithophores in the North Atlantic during the Mid-Pleistocene ...

• Main Authors: Hernández-Almeida, Iván, Guitián, José, Tanner, Thomas, Zhang, Hongrui, Stoll, Heather M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2023
• Subjects: Carbon isotope fractionation; North Atlantic; Mid-Pleistocene transition; Alkenone; Paleobarometry; Growth rate; Coccolithophore; Surface ocean; Primary productivity
• Online Access: https://dx.doi.org/10.3929/ethz-b-000610131; http://hdl.handle.net/20.500.11850/610131

The carbon isotopic fractionation during photosynthesis (Ɛp) from sedimentary alkenone biomarkers produced by coccolithophores is a widely used proxy for concentrations of past dissolved CO2 in seawater (CO2[aq]). Currently, Ɛp records covering the last 1 Myr exist only for low-latitudes regions, which are characterized by stratified waters and nutrient (NO3− and PO4−) limitation. Higher latitudes are affected by more variable hydrographic conditions which are expected to produce larger changes in factors which are important for Ɛp, such as light, temperature, CO2 and growth rate. Understanding these processes at high latitudes is important in order to derive correct estimates of past CO2 concentrations. Here we present new Ɛp and alkenone-based SST records and a review of previously published paleoceanographic multi-proxy datasets, from sites across a latitudinal transect in the North Atlantic (61°37°N) covering the interval between ∼800 and 400 ka. During this period, the subpolar hydrographic fronts ... : Quaternary Science Reviews, 309 ...