SOIL 415 & on Zoom
Join us Wednesdays at 3:30 for our fall departmental seminar series. This week's guest is Jennifer Murphy, Professor in the Department of Chemistry at the University of Toronto.
Title: "Soil-atmosphere exchange of ammonia in agricultural, urban, and Arctic ecosystems"
Abstract: Ammonia is a key nutrient in many ecosystems and is known to be able to undergo bi- directional exchange between the soil and the air, regulated by chemical and physical properties of the system. This talk provides an overview of some work from my group during the last decade that seeks to understand the processes and controlling variables driving ammonia fluxes. Our eddy covariance flux measurements of ammonia above fertilized corn fields over two growing seasons suggest that management practices and environmental conditions can control the magnitude, and even direction, of ecosystem-atmosphere ammonia flux. In the city of Toronto, we observe high concentrations of ammonia whose variability suggests that exchange with urban greenspaces could be important. Using a range of urban soil samples, we evaluated different isotherm approaches to representing environmental soil porewater ammonium concentrations with significant consequences for flux estimates. During fieldwork in the high Arctic, we found indirect evidence that even tundra soils may act as a source of atmospheric ammonia, especially with climate warming.
Jennifer Murphy is a Professor in the Department of Chemistry at the University of Toronto, where she teaches and mentors a team of researchers who focus mainly on understanding the sources and fates of atmospheric pollutants and greenhouse gases. Her team has performed fieldwork across Ontario and in California, Utah, Colorado, northern Michigan, the Alberta oil sands region, and the Canadian Arctic. They deploy scientific instruments at ground sites, on tall towers, stratospheric balloons, aircraft and ships to measure chemicals in the atmosphere. In addition, they leverage government monitoring datasets to characterize spatial and temporal trends in air pollution and the roles of emissions and meteorology.
She served as a member of the Scientific Steering Committee of International Global Atmospheric Chemistry (IGAC) project from 2016 to 2020, and as an Associate Editor at Journal of Geophysical Research - Atmospheres since 2020. In 2019, she was the recipient of an American Geophysical Union Ascent Award for mid-career excellence in atmospheric science. In 2020, she was a member of the team that won the Brockhouse Canada Prize for Interdisciplinary Research in Science and Engineering, and in 2024 she received the Canadian Society of Chemistry’s Clara Benson Award.
Jennifer completed her BSc at McGill University (2000) in Chemistry and a minor in Environmental Studies. During her PhD in Chemistry at the University of California Berkeley (2005), she tracked the sources of air pollution influencing the deposition of nutrients to Lake Tahoe and studied smog in central California. As a postdoctoral fellow at the University of East Anglia (2006), she operated a mass spectrometer aboard a research aircraft flying over West Africa to measure volatile organic compounds emitted from tropical forests.