Published: 16-12-2020| Version 1 | DOI: 10.17632/7cfnfk63b7.1
VIctor Rivera-Monroy


1) DESCRIPTION/ABSTRACT: It is assumed that to treat excess NO3- (> 30 μM), high soil organic matter content (%OM) is required to maintain high denitrification rates in natural, created, or restored wetlands. However, this excess also represents a risk by increasing OM decomposition rates triggering peat collapse. Here, we evaluated the role of soil %OM and temperature interactions in controlling total and net denitrification rates using the isotope pairing and N2:Ar techniques in different habitats within eroding (Barataria Bay-BLC) and emerging (Wax Lake Delta -WLD) deltaic regions in coastal Louisiana. Soil and sediment cores were collected during summer, spring and winter (2015-2016) and incubated at close to in-situ temperatures (i.e., 30, 20 and 10 oC). Denitrification rates were linearly correlated with temperature with maximum mean rates (40.1–124.1μmol m-2 h-1) in the summer (30 oC) and lower (<26.2 ± 5.3 μmol m-2 h-1) in the winter (10 oC) seasons. Direct denitrification was higher than coupled denitrification in all seasons; rates were consistently higher in WLD wetland habitats when compared to an older but degrading BLC wetland, despite of lower soil %OM and higher BD at WLD. Denitrification rates in benthic habitats were similar in both locations. We propose that even in environments with low carbon availability, high denitrification rates can be sustained as long as NO3- concentrations are high (>30 μM) and water temperature is >10 oC. In coastal Louisiana, substrates under these environmental regimes are represented by emergent supra-tidal flats or land created by sediment diversions under oligohaline conditions (<1 ppt). 1) DATA SET: Upret et al Data_DENITRIFICATION RATES denitrification rates obtained in experimental cores in different wetland habitats 2) DATA SET: Upreti et al SEDIMENT DATA Wetland soils sediment physicochemical variables (core sediments)