A global dataset of fossil foraminifera to examine how marine ecosystems changed

We compiled a global dataset of fossil foraminifera to reveal how marine ecosystems changed during the major climate transition from the warm Eocene to the cooler Oligocene, a period marked by Antarctic glaciation and major changes in ocean circulation. We show that ecological change was not a single abrupt event but unfolded over an extended interval. Foraminifera in different regions of the ocean experienced shifts at divergent times.

Fig: General trajectories of foraminiferal species richness.

Our study finds that extinction, migration, and ecological restructuring overlapped in complex ways rather than occurring in a clean sequence. Changes in temperature, nutrient availability, and circulation patterns all played interacting roles in shaping these responses. We find that community turnover involved both losses and the reorganisation of surviving species. Overall, the paper concludes that the Eocene–Oligocene transition represents a prolonged, multi-phase transformation of marine ecosystems. It highlights the importance of viewing major climate-driven biotic changes as dynamic and regionally variable processes rather than singular global tipping points.

Links:

• Complex marine ecological response during the Eocene-Oligocene revealed by global foraminiferal record. Nature Communications 2026
• Prof Bridget Wade - academic profile