Tom Oliver Lecture Series

About the Series

The Tom Oliver Lecture Series is a public lecture series hosted by the Department of Earth, Energy, and Environment in the Faculty of Science. Normally taking place annually, the series seeks to bring in internationally renowned researchers to present stimulating lectures on topics of fundamental interest to the Department of Earth, Energy, and Environment, and the broader UCalgary community. 

About Dr. Tom Oliver

Dr. Tom Oliver founded UCalgary’s Department of Geology in 1959 and was a former head of the department (1963-65) and dean of the Faculty of Science (1978-84). Dr. Oliver provided outstanding leadership as a researcher, instructor and administrator, and as the dean, assisted with the development of the geophysics program and the dramatic growth of the department in the late 1970s. He is remembered as an inspirational teacher, leader, respected petroleum geologist, humanist and humorist.

Arial view of forest
Dr. Russell Callahan

Dr. Russell Callahan

Lithologic and climatic controls on subsurface weathering and ecosystem dynamics in the Sierra Nevada, California, USA

The breakdown of rock near Earth’s surface due to chemical and physical weathering processes releases nutrients and creates pore-space for water storage making it vital to sustaining terrestrial ecosystems. However, subsurface weathering is not uniform across landscapes and can vary with factors such as bedrock composition and climate. Here I will explore how variations in weathering influence ecosystem productivity and forest drought response across seven sites with variations in lithology and climate in the Sierra Nevada batholith, California. Results suggest that lithology is as important as climate in dictating the magnitude of forest dieback during the 2011-2017 California drought. These findings have important implications for understanding and managing forest ecosystems under a changing climate.

Date:  Wednesday, April 10, 2024
Time:  12:15 p.m - 1:15 p.m.
Location:  University of Calgary, Downtown Campus (906 8 Ave SW, Calgary)
Presenter: Dr. Russell Callahan, Assistant Professor at University of Connecticut

Bio:  Dr. Russell Callahan is an Assistant Professor at University of Connecticut. His research focuses on understanding how the depth and extent of subsurface weathering varies across landscapes and how variations in weathering influence hydrologic and ecosystem processes. His works uses a variety of methods including near-surface geophysics, geochemical analyses, and remote sensing. Russell received his Ph.D from the University of Wyoming where he worked with the Critical Zone Collaborative Network to understand connections between weathering and ecosystems in the Sierra Nevada, California. He also completed a postdoc in the Watershed Hydrology Lab at University of California, Santa Cruz where he collaborated with hydrologists to understand how subsurface weathering influences hydrologic partitioning in the critical zone.