Xu Zhihao, Yang Zhifeng, Yin Xinan, Cai Yanpeng, Sun Tao
State Key Laboratory of Water Environmental Simulation, School of Environment, Beijing Normal University, No. 19, Xinjiekouwai Street, Haidian District, Beijing, 100875, China.
J Environ Manage. 2016 Jul 15;177:84-92. doi: 10.1016/j.jenvman.2016.03.046. Epub 2016 Apr 13.
Wetland eutrophication is a global environmental problem. Besides reducing pollutant emissions, improving nutrient assimilative capacity in wetlands is also significant for preventing eutrophication. Hydrological management can improve nutrient assimilative capacity in wetlands through physical effects on the dilution capacity of water body and ecological effects on wetland nutrient cycles. The ecological effects are significant while were rarely considered in previous research. This study focused on the ecological effects of hydrological management on two crucial nutrient removal processes, plant uptake and biological denitrification, in plant-dominated wetlands. A dual-objective optimization model for hydrological management was developed to improve wetland nitrogen and phosphorus assimilative capacities, using upstream reservoir release as water regulating measure. The model considered the interactions between ecological processes and hydrological cycles in wetlands, and their joint effects on nutrient assimilative capacity. Baiyangdian Wetland, the largest freshwater wetland in northern China, was chosen as a case study. The results found that the annual total assimilative capacity of nitrogen (phosphorus) was 4754 (493) t under the optimal scheme for upstream reservoir operation. The capacity of nutrient removal during the summer season accounted for over 80% of the annual total removal capacity. It was interesting to find that the relationship between water inflow and nutrient assimilative capacity in a plant-dominated wetland satisfied a dose-response relationship commonly describing the response of an organism to an external stressor in the medical field. It illustrates that a plant-dominated wetland shows similar characteristics to an organism. This study offers a useful tool and some fresh implications for future management of wetland eutrophication prevention.
湿地富营养化是一个全球性的环境问题。除了减少污染物排放外，提高湿地的养分同化能力对于防止富营养化也具有重要意义。水文管理可以通过对水体稀释能力的物理影响以及对湿地养分循环的生态影响来提高湿地的养分同化能力。生态影响显著，但在以往研究中很少被考虑。本研究聚焦于水文管理对以植物为主的湿地中两个关键养分去除过程（植物吸收和生物反硝化）的生态影响。开发了一个水文管理的双目标优化模型，以上游水库放水作为水调节措施，以提高湿地的氮磷同化能力。该模型考虑了湿地生态过程与水文循环之间的相互作用，以及它们对养分同化能力的联合影响。选择中国北方最大的淡水湿地白洋淀作为案例研究。结果发现，在上游水库运行的最优方案下，氮（磷）的年总同化能力为4754（493）吨。夏季的养分去除能力占年总去除能力的80%以上。有趣的是，发现在以植物为主的湿地中，水流与养分同化能力之间的关系满足一种剂量-反应关系，这种关系通常用于描述医学领域中生物体对外界应激源的反应。这表明以植物为主的湿地表现出与生物体相似的特征。本研究为未来湿地富营养化防治管理提供了一个有用的工具和一些新的启示。
