Single-species dinoflagellate cyst carbon isotope ecology across the Paleocene-Eocene Thermal Maximum

Abstract

We present the first ever species-specific fossil dinoflagellate cyst stable carbon isotope (δ13C) records, from the Bass River Paleocene- Eocene Thermal Maximum (PETM) section in New Jersey (USA), established using a novel coupled laser ablation- isotope ratio mass spectrometer setup. Correspondence with carbonate δ13C records across the characteristic negative carbon isotope excursion indicates that the δ13C of dissolved inorganic carbon exerts a major control on dinocyst δ13C. Pronounced and consistent differences between species, however, reflect different habitats or life cycle processes and different response to pCO2. Decreased interspecimen variability during the PETM in a species that also drops in abundance suggests a more limited niche, either in time (seasonal) or space. This opens a new approach for ecological and evolutionary reconstructions based on organic microfossils.