Xuzhou University of Technology, No. 2 Lishui Road, New City District, Xuzhou 22111, China.
Soil and Water Science Department at Tropical Research and Education Center, IFAS, University of Florida, 18905 SW 280th Street, Homestead, FL 33031, USA.
Int J Environ Res Public Health. 2018 Aug 30;15(9):1882. doi: 10.3390/ijerph15091882.
The Everglades, a vast subtropical wetland, dominates the landscape of south Florida and is widely recognized as an ecosystem of great ecological importance. Data from seven inflow sites to the Everglades National Park (ENP) were analyzed over three decades (1985⁻2014) for temporal trends by the STL (integrated seasonal-trend decomposition using LOESS) method. A cluster analysis (CA) and principal component analysis (PCA) were applied for the evaluation of spatial variation. The results indicate that the water quality change trend is closely associated with rainfall. Increasing rainfall results in increasing flow and thus, decreasing concentrations of nitrogen and phosphorus. Based on 10 variables, the seven sampling stations were classified by CA into four distinct clusters: A, B, C, and D. The PCA analysis indicated that total nitrogen (TN) and total phosphorus (TP) are the main pollution factors, especially TN. The results suggest that non-point sources are the main pollution sources and best management practices (BMPs) effectively reduce organic nitrogen. However, TN and TP control is still the focus of future work in this area. Increasing the transfer water quantity can improve the water quality temporarily and planting submersed macrophytes can absorb nitrogen and phosphorus and increase the dissolved oxygen (DO) concentration in water, continuously improving the water quality.
大沼泽地，一片广阔的亚热带湿地，主宰着佛罗里达州南部的景观，被广泛认为是具有重要生态意义的生态系统。对 1985 年至 2014 年期间流入大沼泽地国家公园（ENP）的七个入口点的数据，采用 STL（使用 LOESS 的集成季节性趋势分解）方法进行了 30 多年的时间趋势分析。采用聚类分析（CA）和主成分分析（PCA）评估空间变化。结果表明，水质变化趋势与降雨量密切相关。降雨量增加会导致流量增加，从而降低氮和磷的浓度。基于 10 个变量，通过 CA 将七个采样站分为四个不同的簇：A、B、C 和 D。PCA 分析表明，总氮（TN）和总磷（TP）是主要的污染因素，特别是 TN。结果表明，非点源是主要污染源，最佳管理措施（BMPs）可有效减少有机氮。然而，TN 和 TP 的控制仍然是该地区未来工作的重点。增加调水水量可以暂时改善水质，种植沉水植物可以吸收氮磷，增加水中溶解氧（DO）浓度，持续改善水质。
