Extreme weather event impacts on soil physical and chemical properties within riparian ecosystem

Riparian zone dynamics in the Northeast United States are particularly vulnerable to extreme weather events (e.g. floods, heat waves, cold snaps) that are projected to increase in response to global climate change (Betts, 2017; Hayhoe et al., 2007). Extreme weather events can alter physical soil characteristics, subsequently impacting the nitrogen (N) removal efficiency of riparian soils. For example, the efficiency of denitrification (i.e. microbially mediated nitrate reduction) varies with soil wetness and associated soil oxygen availability. Capturing such stochastic events and subsequent changes in physical (e.g. temperature and soil moisture) and chemical (e.g. substrate quality) soil characteristics is challenging. Therefore, the effect of extreme weather events on soil denitrification and other N cycling mechanisms is not well understood.

This research addresses this knowledge gap by using an extensive soil sensor network to provide continuous data on CO2, O2, oxidation/ reduction potential, volumetric water content, electrical conductivity, and temperature at two riparian sites (agricultural and forested) in Vermont, USA. Additionally, we quantified soil N and carbon content, as well as dissolved N and organic carbon (C) in percolating soil water on a weather event-based scale. These data will be used to investigate if riparian soil N and C content vary according to adjacent land cover and with soil physical and chemical properties in response to weather events. Preliminary results indicate the response of riparian soil properties to weather events may be particularly sensitive to antecedent soil conditions, especially in summer months.