Effects of land use on the timing and magnitude of dissolved organic carbon and nitrate fluxes: a regional analysis of high-frequency sensor measurements from forested, agricultural, and urban watersheds


TitleEffects of land use on the timing and magnitude of dissolved organic carbon and nitrate fluxes: a regional analysis of high-frequency sensor measurements from forested, agricultural, and urban watersheds
Publication TypePoster
Year of Publication2017
AuthorsSeybold, EC, Gold, A, Inamdar, S, Pradhanang, S, Bowden, WB, Vaughan, M, Addy, K, Shanley, JB, Vermilyea, A, Sleeper, R, Levia, D, Adair, EC, Wemple, B, Schroth, AW
Conference Name2017 AGU (American Geophysical Union) Fall Meeting
Date Published2017/12
PublisherAmerican Geophysical Union (AGU)
Conference LocationNew Orleans, LA
Abstract

Land use/land cover change has been shown to have significant impacts on nutrient loading to aquatic systems, and has been linked to coastal zone hypoxia and eutrophication of lake ecosystems. While it is clear that changes in land use/land cover are associated with changes in aquatic ecosystem function, a mechanistic understanding of how nutrient fluxes from distinct land cover classes respond to hydrologic events on event and seasonal scales remains unknown. Recent advances in the availability of high-frequency water quality sensors provide an opportunity to assess these relationships at a high temporal resolution.

We deployed a network of in-situ spectrophotometers in watersheds with predominantly forested, agricultural, and urban land uses that spanned a latitudinal gradient in the northeastern US from Vermont to Delaware. Our study sought to assess how land cover affected the timing and magnitude of fluxes of carbon (C) and nitrogen (N) from watersheds with distinct land uses, and to determine whether these relationships varied regionally.

We found systematic differences in the timing and magnitude of C and N fluxes and strong variation in the annual mass fluxes from these distinct land cover classes. In particular, we found that while the phenology of C and N fluxes varied across land uses, there were distinct regional similarities in the C and N flux regimes within a given land use class. We also found strong inter-annual variability in carbon and nitrogen fluxes in response to inter-annual variability in precipitation and discharge, suggesting a high degree of hydrologic control over nutrient loading. These findings also emphasize the potential for climate change, and in particular precipitation variability, to drive strong variation in the magnitude of downstream nutrient flux to receiving lakes and estuaries. Our study emphasizes the pervasive influence of land cover and its effects on water quality, and also highlights the strong signature of anthropogenic land use choices on regional C and N cycling.

URLhttps://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/277687
Status: 
Published
Attributable Grant: 
BREE
Grant Year: 
Year2
Acknowledged VT EPSCoR: 
Ack-Yes