Visiting Speaker - Dr. Magali Nehemy

The Department of Geological Sciences and Geological Engineering Visiting Speaker Series Presents:

Dr. Magali Nehemy, Trent University

Talk Title: Ecohydrological coupling (and decoupling): transpiration and streamflow water sources

Date: Friday, January 26

Time: 10:30 am - 11:30 am

Location: Miller Hall, Room 201

Coffee and treats will be served.

Abstract: Forests cover about 30% of the world’s land surface and provide drinking water for billions of people. Despite their significance, forest ecosystems face rapid climate change and anthropogenic disturbances while we have little understanding of those impacts of long-term water availability and forest water use. Forest water use has been investigated through paired watershed studies. While providing insights at a watershed scale, paired watershed studies are a ‘black box approach’, offering limited understanding of the underlying mechanisms driving forest water use, transpiration sources, and their effects on streamflow. Natural tracers of water (stable isotopes of hydrogen and oxygen) provide unique opportunities to investigate forest water use mechanistically, providing understanding of transpiration source water and the age of transpiration. In this talk, I will provide new insights gained using stable isotopes regarding the hydrological coupling and decoupling between transpiration source water and streamflow. Through a synthesis of controlled experiments and field investigations across diverse biomes, I will emphasize the significance of incorporating tree hydraulic traits, storage dynamics, and topography in the exploration of forest water use. This holistic approach promises to enhance our comprehension of the intricate relationships governing water dynamics within forest ecosystems.

Bio: Magali Nehemy is an assistant professor in the School of the Environment at Trent University. Her general research interests centre on water sustainability in the context of forest water use. Her specific research interests focus on ecohydrology and field-based process descriptions of how forests exploit subsurface water storage. She works in boreal and temperate systems in Canada, New Zealand, and tropical systems in Brazil to understand the connectivity between water sources for transpiration and streamflow at different spatial and temporal scales. Her research also focusses on developing new field-based approaches for understanding transpiration phenology and isotopic tracing techniques. This research breaks down the disciplinary boundaries between hydrology, soil science and ecophysiology. Nehemy also co-teaches a national level graduate course in "Isotope Tracers in Catchment Hydrology" open to any graduate student.