University of Florida-IFAS, United States of America.
University of Florida-IFAS, United States of America.
Sci Total Environ. 2020 Jul 10;725:138442. doi: 10.1016/j.scitotenv.2020.138442. Epub 2020 Apr 4.
Stormwater treatment areas (STAs) are an integral component of the Everglades restoration strategies to reduce phosphorus (P) loads from adjacent agricultural and urban areas. The overall objective of this study was to determine the forms and distribution of P in floc and soils along the flow-path of two parallel flow-ways (FWs) in STA-2 with emergent aquatic vegetation (EAV) and submerged aquatic vegetation (SAV), respectively, to assess their stability and potential for long term storage. In EAV high organic matter accretion supported low bulk density and high P concentrations in floc and soil, while high mineral matter accretion in SAV resulted in high bulk density and low P concentrations. Approximately 25-30% of the total P is identified as highly reactive P (HRP) pools, 50-60% in moderately reactive P (RP) forms, and 15-20% in the non-reactive P (NRP) pool. Within HRP and RP pools, a large proportion of P in the SAV areas was inorganic while organic P was more dominant in the EAV areas. Enrichment of total P (especially in HRP and RP pools) found in the upstream areas of both FWs resulted from the P loading into FWs over time, and the surplus P conditions can potentially support flux into the water column. In EAV FW, approximately 45% of the P retained was recovered in floc and RAS and remaining was possibly retained in the above and below ground biomass and incorporated into subsurface soils. In SAV FW, all of the P retained was recovered in floc and soils suggesting P retention in plants was not significant. For STAs to continue to function effectively and meet the desired outflow TP concentrations, management strategies should be aimed to promote P limiting conditions within the system to avoid release of P from floc and soils to water column and potential downstream transport.
雨水处理区（STAs）是大沼泽地修复策略的一个组成部分，旨在减少来自相邻农业和城市地区的磷（P）负荷。本研究的总体目标是确定在分别具有挺水植被（EAV）和沉水植被（SAV）的两个平行流道（FWs）的沿程中，P 在絮体和土壤中的形态和分布，以评估它们的稳定性和长期储存潜力。在 EAV 中，高有机质积累支持低体密度和高 P 浓度的絮体和土壤，而 SAV 中的高矿物质积累导致高体密度和低 P 浓度。大约 25-30%的总 P 被确定为高反应性 P（HRP）池，50-60%为中反应性 P（RP）形式，15-20%为非反应性 P（NRP）池。在 HRP 和 RP 池中，SAV 区的大部分 P 为无机形式，而 EAV 区的有机 P 更为主要。两个 FW 的上游区域总 P（特别是 HRP 和 RP 池中）的富集是由于 FW 中随时间推移的 P 加载，过剩的 P 条件可能会支持向水柱中的通量。在 EAV FW 中，大约 45%的保留 P 在絮体和 RAS 中回收，其余可能保留在地上和地下生物量中，并合并到地下土壤中。在 SAV FW 中，所有保留的 P 都在絮体和土壤中回收，这表明植物对 P 的保留并不重要。为了使 STAs 继续有效地发挥作用并达到预期的流出总磷浓度，管理策略应旨在促进系统内的 P 限制条件，以避免 P 从絮体和土壤释放到水柱和潜在的下游运输。
