Deccan Volcanism: Catalyst for Tropical Flora Resilience and Diversification Despite Mass Extinctions

New Study Highlights How 66-Million-Year-Old Volcanic Activity Boosted Tropical Angiosperms' Evolution.

A groundbreaking study by the Birbal Sahni Institute of Palaeosciences (BSIP), an autonomous institute under the Department of Science and Technology, sheds light on the role of Deccan Volcanism in shaping tropical flora. While this volcanic event—occurring approximately 66 million years ago—contributed to the mass extinction of dinosaurs and other fauna, it paradoxically paved the way for the diversification of angiosperms (flowering plants) by creating fertile, undisturbed habitats ideal for their evolution.

The Role of Deccan Volcanism in Ecological Transformations

The volcanic activity, which persisted for several hundred thousand years across the Cretaceous-Paleogene (K-Pg) boundary, had devastating effects on terrestrial faunas, including dinosaurs. However, contrary to prior assumptions, the new study reveals that tropical flora not only survived but thrived, leveraging the ecological opportunities presented by the extinction of dominant fauna and gymnosperms.

Researchers attribute this resilience to the following factors:

• The warm and humid climate during dormant volcanic phases.
• Nascent barren landscapes enriched with volcanic nutrients.
• The latitudinal shift of the Indian Plate within the Inter Tropical Convergent Zone (ITCZ), which fostered diverse habitats.

These conditions facilitated the rapid diversification of angiosperms within the Indian subcontinent, suggesting that tropical rainforests, if left undisturbed, could recover swiftly under favorable climatic conditions.

Research Methodology and Findings

The study utilized cutting-edge palynology and palynofacies analyses to reconstruct paleoecological and paleoclimatic scenarios.

• Sedimentary Samples: Rock samples, including mudstone and claystone, were collected from a 17-meter-thick sedimentary sequence in Yeotmal, Maharashtra.
• Palynological Analyses: Pollen, spores, and organic matter were extracted using acid digestion techniques.
• Paleobiogeographic and Climatic Models: Researchers applied the Nearest Living Relative (NLR) and Coexistence Approach (CA) to understand floral evolution and environmental conditions.

Published in the journal Earth Science Reviews, the study underscores that despite the release of toxic greenhouse gases and a global temperature surge during Deccan Volcanism, tropical flora displayed remarkable resilience. Within a sub-millennial timeframe, plant communities adapted and flourished, emphasizing their robust response mechanisms to climatic stressors.

Implications for Modern Climate Resilience

The findings offer a beacon of hope amid modern climate change concerns. They suggest that understanding historical floral turnovers during geological upheavals can provide insights into contemporary ecosystems’ responses to global warming. The swift recovery of tropical flora after the K-Pg extinction demonstrates the potential for modern rainforests to regenerate if climatic and anthropogenic pressures are mitigated.

New Research Avenues and Additional Insights

Building on these revelations, BSIP plans to:

• Conduct advanced studies on microbial interactions in ancient ecosystems.
• Explore the role of volcanic nutrients in facilitating biodiversity.
• Analyze similar volcanic impacts on flora across other prehistoric extinction events.

This research highlights the importance of protecting and restoring tropical rainforests, emphasizing their resilience and critical role in global biodiversity and climate regulation.