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Use of stable nitrogen isotopes to track plant uptake of nitrogen in a nature-based treatment system
- Source :
- Water Research X, Vol 9, Iss, Pp 100070-(2020)
- Publication Year :
- 2020
- Publisher :
- eScholarship, University of California, 2020.
-
Abstract
- In nature-based treatment systems, such as constructed wetlands, plant uptake of nutrients can be a significant removal pathway. Current methods for quantifying plant uptake of nitrogen in constructed wetlands, which often involve harvesting biomass and assuming that all nitrogen stored in plants was derived from wastewater, are inappropriate in pilot- and full-scale systems where other sources of nitrogen are available. To improve our understanding of nitrogen cycling in constructed wetlands, we developed a new method to quantify plant uptake of nitrogen by using stable isotopes and a mixing model to distinguish between nitrogen sources. We applied this new method to a pilot-scale horizontal levee system (i.e., a subsurface constructed wetland) over a two-year monitoring period, during which 14% of nitrogen in plants was wastewater-derived on average and the remaining plant nitrogen was obtained from the soil. Analysis of nitrogen isotopes indicated substantial spatial variability in the wetland: 82% of nitrogen in plants within the first 2m of the slope came from wastewater while less than 12% of plant nitrogen in the remainder of the wetland originated from wastewater. By combining these source contributions with remote-sensing derived total biomass measurements, we calculated that 150kgN (95% CI=50kgN, 330kgN) was taken up and retained by plants during the two-year monitoring period, which corresponded to approximately 8% of nitrogen removed in the wetland. Nitrogen uptake followed seasonal trends, increased as plants matured, and varied based on design parameters (e.g., plant types), suggesting that design decisions can impact this removal pathway. This new method can help inform efforts to understand nitrogen cycling and optimize the design of nature-based nutrient control systems.
- Subjects :
- Plant uptake
0208 environmental biotechnology
chemistry.chemical_element
Wetland
02 engineering and technology
010501 environmental sciences
Remote-sensing
01 natural sciences
lcsh:TD1-1066
Mixing models
Nutrient
Nature-based treatment
lcsh:Environmental technology. Sanitary engineering
Waste Management and Disposal
Nitrogen cycle
0105 earth and related environmental sciences
Water Science and Technology
Stable isotopes
geography
geography.geographical_feature_category
Nitrogen deficiency
Ecological Modeling
fungi
food and beverages
Nitrogen removal
Pollution
Nitrogen
Isotopes of nitrogen
020801 environmental engineering
chemistry
Wastewater
Environmental chemistry
Constructed wetland
Environmental science
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- Water Research X, Vol 9, Iss, Pp 100070-(2020)
- Accession number :
- edsair.doi.dedup.....e787d8989bbb7f4370cfee56979ba221