Nitrogen removal rates can vary with time, space, and external environmental drivers, but are underreported for karst environments. We carried out a multi‐year study of a karst conduit where we: (a) measured inputs and outputs of sediment nitrogen (SN and δ15NSed) and nitrate (NO3−and δ15NNO3); (b) developed, calibrated, and applied a numerical model of nitrogen physics and biogeochemistry; and (c) forecasted the impacts of climate and land use changes on nitrate removal and export. Data results from conduit inputs (SN = 0.43% ± 0.07%, δ15NSed = 5.07‰ ± 1.01‰) and outputs (SN = 0.36% ± 0.09%, δ15NSed = 6.45‰ ± 0.71‰) indicate net‐mineralization of SN and increase of δ15NSed(
Human‐made stormwater control systems are biogeochemical hotspots, but construction and management may result in homogenization of their ecosystem structure. Roadside ditches are a ubiquitous part of the landscape, yet few studies have quantified their biogeochemical potential. We conducted a study to determine (a) nitrate (NO3−) removal potential through rate measurements and (b) microbial community structure using 16S rRNA gene (iTag) sequencing in roadside ditches draining predominantly forested, urban, and agricultural watersheds surrounding Mobile Bay, AL (USA). We found that nitrogen (N) removal rates by denitrification and anammox dominated over N‐retention by dissimilatory nitrate reduction to ammonium, accounting for upwards of 89% of NO3−reduction on average. There were no differences in soil characteristics between land use types, but denitrification potential rates in forested ditches were less than half of those in urban and agricultural ditches, possibly as a result of differences in vegetation management. Microbial alpha and beta diversity were largely homogenous across the three land use types. However, indicator species analysis revealed putative ammonia oxidizers (
- PAR ID:
- 10449007
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Biogeosciences
- Volume:
- 126
- Issue:
- 7
- ISSN:
- 2169-8953
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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