Water Resources Research Act Program

Details for Project ID 2019VT263B

Identifying drivers of change in denitrification capacity of riparian soils during the spring snowmelt/runoff period

Institute: Vermont
Year Established: 2019 Start Date: 2019-06-18 End Date: 2020-06-17
Total Federal Funds: $9,298 Total Non-Federal Funds: $18,653

Principal Investigators: Brittany Lancellotti

Project Summary: We propose to address a critical knowledge gap in water quality research: the role of microorganisms in nitrogen (N) liberation from riparian zones during the spring runoff period. To do this, we propose to combine high resolution field data from a recently installed riparian soil sensor network with innovative molecular biology techniques. Although nutrient reduction strategies have been focused on phosphorus (P) inputs, Lake Champlain may be becoming increasingly sensitive to nitrogen (N) loading as the Lake’s waters continue to warm and nutrient inputs change. Recent research shows that the delivery of N to Lake Champlain by spring runoff is the dominant pool of riverine N that phytoplankton can utilize in warmer months. N loading to the Lake, the majority of which occurs during snowmelt/spring runoff, is tightly coupled to biogeochemical processes that occur in the soil environment. In particular, riparian areas play a critical role in reducing N inputs because they are hotspots for N removal via microbiallymediated denitrification. Denitrification provides an important ecosystem service, but the process is highly variable. Although some of this variation is explained by environmental factors such as soil moisture and temperature, much variation in denitrification rate and efficiency remains unexplained. With the goal of identifying the variables that account for unexplained variation in denitrification, we propose to study the controls on the biotic (microbial) community, and the impacts of the biotic community on denitrification. The findings of this research will provide a better understanding of how biotic factors, specifically the composition and abundance of microbial denitrifiers, influence the mechanisms that modulate denitrification.