An assessment of nitrogen and phosphorus availability in constructed wetlands in the Cumberland Marsh Region, Canada
LE3 .A278 2016
Bachelor of Science
Earth & Environmental Sciences
The Cumberland Marsh Region (CMR), located on the coast of the Bay of Fundy, is a major feeding ground for waterfowl and contains significant coastal wetland systems. At this site there is concern over the occurrence of wetland senescence (the apparent decline of an ecosystem’s productivity), which appears to be a limiting factor in the viability of the CMR’s constructed wetlands, and results in management challenges. This study focuses on evaluating nitrogen (N) and phosphorous (P) in both surface and groundwater, and assessing the impact of landscape variability, and temporal and quantitative variations of natural and anthropogenic nutrient sources within altered and constructed wetlands. Water analyses were carried out weekly over a 3-month period on ten constructed freshwater wetlands, one altered freshwater wetland and three ground water sites. Results indicate that the impact of regional N and P sources on the sampled wetland sites is relatively low, and P loading is primarily autochthonous. These observations are supported by low N readings (<3 mg/L) at all sites with little seasonal variation, and higher (eutrophic) P levels that fluctuate without external input (40—300 μg/L) most notably in newly constructed wetlands. Although land use may not be an important contributor to N levels in surface water, a relatively high (5 mg/L) ground water reading suggests that anthropogenic sources exist. These results imply that nutrient sources, inputs, and pathways should be examined when choosing a potential wetland site to avoid the monetary and ecological losses associated with senescent constructed wetland.
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