ANNOUNCEMENTS
This study investigates the impact of Deccan volcanism on planktic foraminiferal communities at Elles, Tunisia, immediately preceding the Cretaceous-Paleogene (K/Pg) boundary. Using a combination of population, morphometric, and preservation analyses, we document a consistent decline in the absolute and relative abundance of large, heavily calcified planktic foraminifera within the final 60 cm of the Maastrichtian (zone CF1), highlighting increasing vulnerability to environmental stress. Concurrently, we observe a rise in opportunistic taxa and a synchronous decline in both generalist and specialist species, indicating intensifying ecological disruption. Morphometric data reveal significant size reductions (dwarfing) and thinning of test walls in all studied species, both classic stress responses to reduced carbonate availability and ocean acidification. These biological and taphonomic indicators—together with an increased fragmentation index and correlations with mercury anomalies—align with known pulses of Deccan volcanism, suggesting recurrent episodes of calcification stress and ocean acidification that began nearly 40,000 years before the K/Pg boundary and intensified in the final 20,000 years. These results support a scenario where volcanic CO₂ and SO₂ emissions from the Deccan Traps initiated a phase of ecological decline in marine planktonic ecosystems, culminating in the abrupt biotic turnover at the K/Pg boundary.
Keywords: Deccan volcanism, K/Pg boundary, planktic foraminifera, ocean acidification, ecological stress, carbonate undersaturation.
