Faculty Research Fellows Hutyra, Templer Co-Author Two Papers on Nitrogen Deposition in Urban Areas

Lucy Hutyra and Pamela Templer, Professors in the Departments of Earth & Environment and Biology, respectively, and Faculty Research Fellows at the Frederick S. Pardee Center for the Study of the Longer-Range Future, recently co-authored two papers related to their Pardee Center research on urban nitrogen deposition. The lead author of both papers, Stephen Decina of the Templer Lab, successfully defended his PhD in the Department of Biology in October 2017.

In the first paper, titled “Variability, drivers, and effects of nitrogen deposition across an urban area: emerging patterns among human activities, the atmosphere and soils” and published in Science of the Total Environment, the authors explain that little is known about the variability and drivers of atmospheric nitrogen inputs or their effects on soil in urban areas. This is because monitoring networks generally only try to capture regional patterns of deposition, or use only one or two urban sites in an urban-rural comparison. This study used 15 sites across greater Boston to demonstrate high variability in rates of urban throughfall (i.e. tree canopy drip) nitrogen inputs, a correlation of throughfall nitrogen inputs with local vehicle nitrogen emissions, and a decoupling of urban soil biogeochemistry and throughfall N inputs.

In the second paper, titled “Atmospheric Inputs of Nitrogen, Carbon, and Phosphorus across an Urban Area: Unaccounted Fluxes and Canopy Influences” and published in Earth’s Future, the authors studied atmospheric inputs of organic nitrogen, organic carbon, and inorganic phosphorous in cities, all of which can affect ecosystem processes, water quality, and air quality. They found that the urban atmosphere is a significant source of these inputs — particularly phosphorous — which may impact efforts to improve water quality. In addition, atmospheric inputs were found to be elevated beneath tree canopies, so as cities encourage tree planting policies it may be essential to locate those trees above permeable surfaces to reduce nutrient runoff.

As Faculty Research Fellows at the Pardee Center, Hutyra and Templer lead a project that established the first urban nitrogen monitoring stations in Boston (on the BU campus and throughout the City of Boston) as part of the National Atmospheric Deposition Program (NADP). This urban monitoring network complements the larger biogeochemistry research program at BU, which is seeking to understand the sources and transformations of emissions and deposition of nitrogen in Boston in order to make predictions about future atmospheric nitrogen deposition rates.