Elena Robakiewicz
PhD Defense
June 21st, 2023 – 10 AM EST
Location: Beach Hall, University of Connecticut, Room 233
WebEx Link: WebEx UConn Earth Sciences
Environment and Lake Systems Across Africa: Understanding the Relationship between Environments, Lakes, and Hominins
The African continent has been prone to environmental and hydroclimatic changes resulting from global climate change – a reality that not only impacts modern human populations, but also early hominins. Massive changes in precipitation and therefore lake levels occur over short time periods across Africa, particularly in the east, where as recently as 5 thousand years ago (ka) hyper-arid regions were instead lakes hundreds of meters deep. Whether to prepare for impacts of anthropogenic climate change or to determine the environmental variables that may have impacted the physical and technological evolution of early humans, determining how global forces impact local environments is crucial. Modern studies to determine climatic controls on water bodies and multi-proxy paleolake records to reconstruct past hydroclimates are necessary to uncover the evolving and dynamic relationship between environments and global climate change which varies across both space and time.
This dissertation explores these themes by examining lake variability across multiple time periods at multiple scales across Africa. The first chapter explores lake variability at Paleolake Suguta, Kenya across ~100,000 years during the Early/Mid-Pleistocene Transition (1,200–700 ka) when glacial cycles transitioned from 41,000- to 100,000-year cycles. The second chapter identifies lacustrine change at Lake Nakuru, Kenya over the last 35 ka, encompassing the dry Last Glacial Maximum (26-19.5 ka) and the wet African Humid Period (15-5 ka). The third chapter is a modern study of hydrochemistry on the Humpata Plateau, Angola to determine controls on diatom assemblages (a useful hydrochemistry and pollution proxy) in an understudied region.
These chapters highlight the importance of in-depth multi-proxy studies to understand the complex dynamics that impact a local area’s hydroclimate and provide insight into how climate change causes variability in lake levels, precipitation, and hydrochemistry. As researchers continue to uncover hydroclimates across the Quaternary, there is hope that furthering knowledge on the relationship between global climate and local environments will lead to discoveries into the hominin evolution and technological change as well as governmental plans and policies to adapt to a future and uncertain, anthropogenically-driven climate state.
For more information, contact: Christin Donnelly at christin.donnelly@uconn.edu