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Understanding Controls on Dissolved Organic Carbon Quantity and Quality in United States Watersheds
Kevin
Hanley, University of New Hampshire, kwz22@unh.edu
Dissolved organic carbon (DOC) in rivers is a critical component of the global carbon cycle and both its quantity and quality are important parameters in numerous fields of study, from water quality to coastal oceanography. Previous studies have considered bulk DOC quantity at various spatial and temporal scales, but little such work has been done with respect to quality. In order to better understand the processes by which DOC enters, is processed within, and is transported by riverine systems, we analyzed DOC concentration and SUVA254 at approximately 2000 USGS gauging stations throughout the United States and related them to remote sensing information. Watersheds ranged from small headwater streams to continental-scale rivers. We focused on characterizing the temporal variability of DOC entering aquatic systems from land in the headwaters, and on annual averages for larger systems. We expected that remotely sensed basin-characteristics like land cover type, vegetation indices such as MODIS NDVI and EVI, and moisture indices such as MODIS LSWI would be useful in explaining DOC variability in space and time among headwaters and we expected that significant in-stream transformation would become evident in the larger basins. Preliminary results indicate a strong link between the percent wetland-cover of large watersheds and both bulk DOC concentration (R2=0.78, p<0.0001) and SUVA (R2=0.91, p<0.0001) at annual scales across a wide range of biomes. Results of these and further analyses will improve understanding of riverine DOC dynamics, constrain estimates of fluxes to the coastal ocean, and aid in the development and testing of continental-scale DOC quantity and quality models. Presentation Type: Poster Session: Coupled Processes at Land-Atmosphere-Ocean Interfaces (Mon 4:00 PM) Associated Project(s):
Poster Location ID: 77
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