Publication Date:
2011-03-02
Description:
Natural abundance of N stable isotopes used in combination with concentrations may be useful indicators of N-cycling in wetlands. Concentrations and 15N signatures of NO3 −, NH4 +, and sediment organic nitrogen (SON) were measured in two impacted coastal golf course retention ponds and two natural marshes. Limited NO3 − was detected in natural site surface water or pore water, but both isotopic signature and concentrations of NO3 − in surface water of impacted sites indicated anthropogenic inputs. In natural sites, NH4 + concentrations were greatest in deeper pore water and least in surface water, suggesting diffusion predominates. The natural sites had greater %SON, and 15N indicated that the natural sites also had greater NH4 + released from SON mineralization than impacted sites. In NO3 −-limited systems, neither concentrations nor 15N natural abundance was able to provide information on N-cycling, while processes associated with NH4 + were better elucidated by using both concentrations and 15N natural abundance.
Print ISSN:
1687-7667
Electronic ISSN:
1687-7675
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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