Event Title

Spectroflurometric and Isotopic Characterization of Organic Matter Along a Gradient of Urban Landuse

Presenter Information

Julie Kelso
Michelle Baker

Location

Eccles Conference Center Auditorium

Event Website

http://water.usu.edu

Start Date

3-31-2015 10:30 AM

End Date

3-31-2015 10:40 AM

Description

Dynamics of allochthonous and autochthonous organic matter (OM) in aquatic systems have been studied for decades, but urban studies have revealed additional, less studied, OM sources such as storm water, lawn clippings and wastewater effluent. We used the natural abundance of carbon, nitrogen and hydrogen isotopes to determine the sources of fine particulate organic matter (FPOM), and dissolved organic matter (DOM), as well as excitation emission matrices (EEMs) to characterize sources of DOM. Organic matter was sampled at 32 sites, in 4 watersheds that encompass a range of urban, suburban, range, and agricultural land uses in north east Utah. The proportional contribution of each source was estimated using the Stable Isotope Analyses in R package. FPOM was composed of a mixture of autochthonous and terrestrial sources (mean = 54%, range 38-68%). DOM carbon and hydrogen isotope signatures indicate primarily terrestrial DOM (d13C mean = -25.9 ‰ ± 0.5‰ and d2H = -98 ‰, ± 15.4‰). DOM spectroscopy indices including the Fluorescence Index, and SUVA254, were variable across all sites suggesting a mixture of microbial and terrestrially DOM regardless of land use.

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Mar 31st, 10:30 AM Mar 31st, 10:40 AM

Spectroflurometric and Isotopic Characterization of Organic Matter Along a Gradient of Urban Landuse

Eccles Conference Center Auditorium

Dynamics of allochthonous and autochthonous organic matter (OM) in aquatic systems have been studied for decades, but urban studies have revealed additional, less studied, OM sources such as storm water, lawn clippings and wastewater effluent. We used the natural abundance of carbon, nitrogen and hydrogen isotopes to determine the sources of fine particulate organic matter (FPOM), and dissolved organic matter (DOM), as well as excitation emission matrices (EEMs) to characterize sources of DOM. Organic matter was sampled at 32 sites, in 4 watersheds that encompass a range of urban, suburban, range, and agricultural land uses in north east Utah. The proportional contribution of each source was estimated using the Stable Isotope Analyses in R package. FPOM was composed of a mixture of autochthonous and terrestrial sources (mean = 54%, range 38-68%). DOM carbon and hydrogen isotope signatures indicate primarily terrestrial DOM (d13C mean = -25.9 ‰ ± 0.5‰ and d2H = -98 ‰, ± 15.4‰). DOM spectroscopy indices including the Fluorescence Index, and SUVA254, were variable across all sites suggesting a mixture of microbial and terrestrially DOM regardless of land use.

https://digitalcommons.usu.edu/runoff/2015/2015Posters/24