Spatial Variability of Sediment Denitrification Across the Atchafalaya River Basin, Louisiana, USA

Autor: Charles W. Lindau, John A. Nyman, Amy E. Scaroni
Rok vydání: 2010
Předmět:
Zdroj: Wetlands. 30:949-955
ISSN: 1943-6246
0277-5212
DOI: 10.1007/s13157-010-0091-1
Popis: Ecosystem-wide denitrification estimates generally depend on the degree of spatial variability in the system, but spatial variability is rarely assessed. To model nitrogen removal rates in the Atchafalaya River Basin we first identified trends in background and potential denitrification across this large floodplain. We conducted a laboratory study to quantify background and potential denitrification rates. Background and potential denitrification rates were significantly different. Background rates ranged from ranged from 0–1.35 μg N g−1 d−1 and potential rates ranged from ranged from 26.72–710.47 μg N g−1 d−1, illustrating the existence of denitrification hotspots across the landscape. Background rates were related to soil characteristics (carbon, nitrogen, nitrate), but potential rates appeared to be related to landscape position (spatial coordinates). Background denitrification showed a strong positive correlation with soil nitrate, and a negative correlation with soil nitrogen and soil carbon. Potential denitrification rates showed no significant correlations with any parameters tested. We observed a significant relationship between location and potential denitrification rates, with greater potential downstream than upstream, but not between location and background rates. This suggests that landscape scale studies should include additional qualifiers, such as habitat type and organic matter quality, for more reliable estimates of denitrification rates.
Databáze: OpenAIRE
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