Brackish water bodies provide critical ecosystem services supporting human and environmental health in coastal regions. Mitigation of contaminants in brackish waters is critical. Floating treatment wetlands (FTWs) are a remediation technology typically applied to improve water quality in freshwater systems. However, the applicability of FTWs to waters with fluctuating salinity has not been determined. The goal of this study was to quantify the growth and survival of four plant species and determine which aquatic macrophytes are suited for use in FTWs deployed in brackish waters. This study trialed four species common to salt marshes of the Southeastern USA (Distichlis spicata, Juncus roemerianus, Spartina alterniflora, and Spartina patens) grown under three salinity exposures (0.5, 5.0, and 18 g⋅L⁻¹) over 7 weeks. We also quantified macro- and micro-nutrient concentrations in these species to enable determination of how plant growth in FTWs may alter nutrient partitioning in roots and shoots. The ratios of nutrients fixed in tissues of plants grown in the salt marsh vs. those grown in FTWs shifted. The ratio of Na:Ca within tissues were higher for plants grown in the saltmarsh than those grown in the FTWs. Regarding biomass production, D. spicata and J. roemerianus grew very little, regardless of salinity exposure. J. roemerianus did not survive at 18 g⋅L⁻¹ salinity. S. alterniflora and S. patens had the highest biomass production and final nutrient concentrations in tissues across all salinities. These trials indicated that of the four species tested, S. alterniflora and S. patens hold the most promise for FTW application in brackish settings.

咸水水体提供重要的生态系统服务，支持沿海地区的人类和环境健康。减少咸水中的污染物至关重要。漂浮处理湿地(FTW) 是一种通常用于改善淡水系统水质的修复技术。然而，FTW 对盐度波动水域的适用性尚未确定。本研究的目的是量化四种植物物种的生长和存活，并确定哪些水生大型植物适合用于部署在咸水水域的 FTW。本研究试验了美国东南部盐沼常见的四种物种（ Distichlis spicata 、 Juncus roemerianus、Spartina alterniflora和Spartina patens）在三种盐度暴露（0.5、5.0 和 18 g⋅L^-1）下生长 7 周。我们还量化了这些物种的宏观和微量养分浓度，以便确定 FTW 中的植物生长如何改变根和芽中的养分分配。在盐沼中生长的植物组织中固定的养分与在盐沼中生长的植物组织中固定的养分比例发生了变化。生长在盐沼中的植物组织内 Na:Ca 的比例高于生长在 FTW 中的植物。关于生物量生产，无论盐度如何，D. spicata和J. roemerianusJ. roemerianus⁻¹下无法存活。在所有盐度下，互花米草和小叶米草具有最高的生物量产量和组织中的最终营养浓度。这些试验表明，在测试的 4 个物种中，互花互花 S. alterniflora和S. patens最有希望在咸水环境中应用 FTW。