Nutrient removal is among the most valuable ecosystem services provided by marshes and is often a stated goal of coastal restoration projects. However, the removal capacity of constructed marshes is potentially affected by several site-specific and design factors, such as marsh platform elevation, slope, sediment type, initial planting density and wave climate. Here, the main and interactive effects of these factors on the capacity of constructed marshes to remove nitrate from runoff was explored in field experiments at sites protected from and exposed to waves. At both sites, three experimental blocks were established, each with 24 treatment combinations of factors in experimental flumes: two platform elevations (high and low), two slopes (steep and shallow), two sediment types (coarse and fine grain), and three initial planting densities (0%, 50% and 100% cover). Nutrient rich (KNO₃) groundwater solution was fed through the marsh rhizosphere using subsurface diffusers. The relative effects of treatment combinations were then assessed by analyzing porewater NO_x concentrations with ANOVA models. None of the treatment combinations had any observable effect on porewater NO_x concentrations at the exposed site. However, both sediment type and planting density were significant main effects at the protected site with the lowest NO_x concentrations found in flumes with fine sediments and initially planted. These results confirm that design factors can have large implications on nutrient dynamics of constructed marshes in areas protected from waves and that wave energy can substantially reduce the influence of these design factors.

养分去除是沼泽提供的最有价值的生态系统服务之一，通常是沿海恢复项目的既定目标。但是，人工湿地的清除能力可能受几个特定地点和设计因素的影响，例如湿地平台的高程，坡度，沉积物类型，初始种植密度和海浪气候。在野外实验中，在远离波浪的地方进行了田间试验，探讨了这些因素对人工沼泽从径流中去除硝酸盐的能力的主要影响和相互作用。在两个站点上，都建立了三个实验区，每个区有24种处理实验水渠的因素组合：两个平台高程（高和低），两个斜率（陡峭和浅层），两种沉积物类型（粗粒和细粒）和三个初始种植密度（0％，50％和100％的覆盖率）。营养丰富（KNO₃）使用地下扩散器将地下水溶液注入沼泽根际。治疗组合的相对效应然后通过分析评估孔隙水NO _X浓度的ANOVA模型。治疗组合的无对孔隙水NO任何可观察到的效果_X在暴露位点的浓度。但是，这两个沉积物类型和种植密度均在与最低无保护的网站显著主效应_X浓度与细颗粒泥沙，最初种植的水槽中。这些结果证实，设计因素可能会对波浪保护区人工湿地的养分动态产生重大影响，并且波浪能可以大大减少这些设计因素的影响。