RESPONSE OF DEEP SEA BENTHIC FORAMINIFERA ACROSS THE EOCENE - OLIGOCENE BOUNDARY OF THE SOUTHERN OCEAN

Abstract

The Cenozoic Era was an eventful interval as the earth experienced many episodes of tectonic, climatic, and oceanographic changes. The Eocene-Oligocene Transition (EOT) witnessed a significant changeover from greenhouse to icehouse climatic conditions. These climatic fluctuations are believed to be caused by the rearrangement of tectonic plates and the change in global ocean water circulation. The Southern Ocean (SO) is crucial to monitoring these changes in the deep ocean environment as it connects three main ocean basins (Pacific, Atlantic, and Indian Oceans) and, consequently, atmospheric pCO2 flux and ocean heat budget. The climatic changes are primarily caused by the opening of different gateways around the Antarctic (e.g., the Drake Passage and the Tasman Passage). The Drake Passage (DP) opening is widely considered to have led to the Antarctic Circumpolar Current (ACC) formation. Many proxies are used to decipher the exact timing of the opening of the Drake Passage, but micropaleontological evidence is vital. However, the timing and associated biotic effects of the opening of the DP remain poorly constrained. Understanding the impact of climate change on the evolution and ecology of organisms is essential for preventing future biodiversity extinction. However, establishing the relationship between climate to ecological and evolutionary patterns of organisms is challenging. So, studying biodiversity dynamics at micro-evolutionary changes through time provides information to understand past biotic responses to climate change and predict biotic responses to future climatic change.