Pan Xu, Ping Yunmei, Cui Lijuan, Li Wei, Zhang Xiaodong, Zhou Jian, Yu Fei-Hai, Prinzing Andreas
Institute of Wetland Research, Chinese Academy of Forestry, Beijing, China.
Beijing Key Laboratory of Wetland Services and Restoration, Beijing, China.
PLoS One. 2017 Jan 27;12(1):e0171019. doi: 10.1371/journal.pone.0171019. eCollection 2017.
Plant litter is an indispensable component of constructed wetlands, but how the submergence of plant litter affects their ecosystem functions and services, such as water purification, is still unclear. Moreover, it is also unclear whether the effects of plant litter submergence depend on other factors such as the duration of litter submergence, water source or litter species identity. Here we conducted a greenhouse experiment by submerging the litter of 7 wetland plant species into three types of water substrates and monitoring changes in water nutrient concentrations. Litter submergence affected water quality positively via decreasing the concentration of nitrate nitrogen and negatively via increasing the concentrations of total nitrogen, ammonium nitrogen and total phosphorus. The effects of litter submergence depended on the duration of litter submergence, the water source, the litter species identity, and the plant life form. Different plant species had different effects on the water nutrient concentrations during litter submergence, and the effects of floating plants might be more negative than that of emergent plants. These results are novel evidence of how the submergence of different plant (life form) litter may affect the purification function of constructed wetlands. For water at low eutrophication levels, submerging a relative small amount of plant litter might improve water quality, via benefiting the denitrification process in water. These findings emphasized the management of floating plant litter (a potential removal) during the maintenance of human-controlled wetland ecosystems and provided a potential tool to improve the water quality of constructed wetlands via submerging plant litter of different types.
植物凋落物是人工湿地不可或缺的组成部分，但植物凋落物的淹没如何影响其生态系统功能和服务（如水质净化）仍不清楚。此外，植物凋落物淹没的影响是否取决于其他因素，如凋落物淹没的持续时间、水源或凋落物物种特性，也不清楚。在此，我们进行了一项温室实验，将7种湿地植物物种的凋落物淹没在三种类型的水体基质中，并监测水体养分浓度的变化。凋落物淹没通过降低硝态氮浓度对水质产生积极影响，同时通过增加总氮、铵态氮和总磷浓度产生负面影响。凋落物淹没的影响取决于凋落物淹没的持续时间、水源、凋落物物种特性和植物生活型。不同植物物种在凋落物淹没期间对水体养分浓度有不同影响，漂浮植物的影响可能比挺水植物更负面。这些结果是关于不同植物（生活型）凋落物的淹没如何影响人工湿地净化功能的新证据。对于低富营养化水平的水体，淹没相对少量的植物凋落物可能通过促进水体中的反硝化过程来改善水质。这些发现强调了在人工控制的湿地生态系统维护过程中对漂浮植物凋落物（一种潜在的去除对象）的管理，并提供了一种通过淹没不同类型的植物凋落物来改善人工湿地水质的潜在工具。
