Nitrogen dynamics in urban grassland landscapes
By Peter M. Groffman
Friday, October 4, WBY 001 at 12:00 pm
Host: Karl Guillard
Peter will have lunch with graduate students and post-docs in WBY 119 after the seminar.
Abstract
In the Baltimore Ecosystem Study (BES), one of two urban long-term ecological research (LTER) projects funded by the U.S. National Science Foundation, we are using “the watershed approach” to integrate ecological, physical and social sciences. Watersheds are a natural (and well-used) physical unit for bio-geo-chemical research and can also function as a focus for human-environment interactions, i.e. bio-geo-socio-chemistry. Suburban watershed input/output budgets for nitrogen (N) have shown surprisingly high retention which has led to detailed analysis of sources and sinks in these watersheds.
Our initial assumptions in BES was that lawns would be “hotspots” of nutrient pollution in the urban landscape due to high rates of fertilizer application and runoff, and low potential for retention of these nutrients in lawn vegetation and soils. However, lawns have more complex coupled carbon and N dynamics than previously thought, motivating us to refer to them as “urban grasslands” to reflect that these are functioning ecosystems, with high potential for N retention, that can hopefully be sustained through management
In this talk, I will present long-term data on the N performance of lawns as well as results from more recent studies on detailed characterization of runoff and denitrification (conversion of reactive N to N gases) in urban grasslands and landscapes. We have also collected extensive social science data on lawn care practices and attitudes that underlie these practices. Data show that urban grasslands and landscapes have a high potential to cycle and retain, as well as to lose N and that the balance between retention and loss is a complex function of social and hydrobiogeochemical processes. Basic science research on these processes, and their interactions improves our basic science understanding of terrestrial ecosystems and can lead to improved management of an important land use/land cover type.
About the Speaker
Peter M. Groffman is a Professor at the City University of New York Advanced Science Research Center and Brooklyn College Department of Earth and Environmental Sciences, and a Senior Research Fellow at the Cary Institute of Ecosystem Studies.
He has research interests in ecosystem, soil, landscape and microbial ecology, with a focus on carbon and nitrogen dynamics. Specific recent research efforts include studies of nitrogen dynamics in urban watersheds, lawns, riparian zones and forests, winter climate change effects on nutrient cycling in forests, calcium/nitrogen/carbon interactions in forests, and the effects of exotic earthworm invasion on soil nitrogen and carbon cycling.
Groffman currently serves on the Scientific and Technical Advisory Committee of the National Ecological Observatory Network (NEON) and was chair of the Science Council of the U.S. National Science Foundation funded Long-Term Ecological Research (LTER) network from 2015 – 2019. He is a participant in LTER projects in Baltimore (urban) and New Hampshire (northern hardwood forests). Groffman was a Convening Lead Author for the 2013 U.S. National Climate Assessment Chapter on Ecosystems, Biodiversity and Ecosystem Services and a lead author for the Second (Wetlands) and Third (North America) Assessment Reports of the Intergovernmental Program on Climate Change (IPCC).
UPCOMING PSLA SEMINARS: http://psla.uconn.edu/SeminarsFall2019.pdf
For more information, contact: PSLA at psla@uconn.edu