No extinction in foraminifera during the Carnian Pluvial Episode (Late Triassic)

The Carnian Pluvial Episode (CPE, Late Triassic, ∼234–232 Ma) was a major climate change characterized by intensified hydrological cycle, perturbations in the carbon cycle, global warming and ocean anoxia. The climate perturbation was coeval to significant biological changes, including extinctions and the emergence of new clades. Research on the climatic changes of the CPE has been conducted extensively across the Tethys domain. However, the high-resolution fossil investigation is very limited, limiting our understanding of the relationship between the CPE and biological changes. Here, we analyzed foraminiferal assemblages, their diversity and abundance in Erguan section of Guizhou (Paleotethys) and Quxia section of South Tibet (Neotethys). The results indicate that, although the global climate and marine environment changed dramatically during the CPE with a transient local impact on the communities, no significant extinctions are recorded among foraminifera in these regions. Foraminifera in Erguan section responded to the CPE mainly with a sharp decrease in diversity and abundance at the beginning of the episode, while in Quxia section they did not show obvious responses. The different biotic responses of foraminifera may reflect variable environmental conditions, such as varying degrees of warming, siliciclastic input and ocean anoxia in the two regions. Our results show that different marine organisms responded differently to the CPE, highlighting the complexity of the impact of Carnian climatic changes on living organisms.