Natural abundance of N stable isotopes used in combination with concentrations may be useful indicators of N-cycling in wetlands. Concentrations and N signatures of NO 3 − , NH 4 + , and sediment organic nitrogen (SON) were measured in two impacted coastal golf course retention ponds and two natural marshes. Limited NO 3 − was detected in natural site surface water or pore water, but both isotopic signature and concentrations of NO 3 − in surface water of impacted sites indicated anthropogenic inputs. In natural sites, NH 4 + concentrations were greatest in deeper pore water and least in surface water, suggesting diffusion predominates. The natural sites had greater %SON, and N indicated that the natural sites also had greater NH 4 + released from SON mineralization than impacted sites. In NO 3 − -limited systems, neither concentrations nor N natural abundance was able to provide information on N-cycling, while processes associated with NH 4 + were better elucidated by using both concentrations and N natural abundance.
Aelion, C. M., Engle, M. R., & Ma, H. (2010). Use of N Natural Abundance and N Species Concentrations to Assess N-Cycling in Constructed and Natural Coastal Wetlands . Applied and Environmental Soil Science, 2010, 1–9. https://doi.org/10.1155/2010/371259