Ji Peng-Fei, Xu Hai, Zhan Xu, Zhu Guang-Wei, Zou Wei, Zhu Meng-Yuan, Kang Li-Juan
School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China.
Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Huan Jing Ke Xue. 2020 Sep 8;41(9):4030-4041. doi: 10.13227/j.hjkx.202002017.
In spring and summer of 2018, 26 lakes in the middle and lower reaches of the Yangtze River were studied to determine the temporal and spatial characteristics of nitrogen and phosphorus ratios (TN/TP) and their influencing factors. The differences in nitrogen and phosphorus ratios in different types of lakes (including water-psaaing lakes, deep reservoirs and eutrophic lakes) and in different seasons were analyzed in terms of the sources of the lakes, lake depth, suspended particulate matter concentrations, and phytoplankton levels. The average TN/TP was 21.52±14.28 in spring and 21.73±23.78 in summer. The TN/TP varied significantly in different types of lakes. The TN/TP ratios in water-passing lakes, deep reservoirs and eutrophic lakes were 20.41±9.25, 40.97±33.37, and 14.38±7.40 during spring, and were 22.62±6.48, 96.38±45.91, and 10.91±4.44 during summer, respectively. The TN/TP of the water-passing lakes and deep reservoirs increased significantly in summer, while that of the eutrophic lakes decreased significantly, which indicates that TN/TP changes and lake nutritional status are closely related. The source of nutrients in lakes and reservoirs affects the TN/TP. The TN/TP of lakes and reservoirs had a significant correlation with the lake depth in both spring and summer, indicating that lake depth is a key factor affecting the ratio of nitrogen and phosphorus. In addition, in eutrophic lakes with higher absolute nutrient concentrations, TN/TP has less effect on phytoplankton, while in deep-water lakes with lower absolute nutrient concentrations, TN/TP can determine the growth of phytoplankton limited by phosphorus. Therefore, the governance strategy of lakes in the middle and lower reaches of the Yangtze River should prioritize phosphorus control. Local digging, controlling non-point source pollution, sediment dredging, and changing fishery production methods can be applied to improve the ecological quality of the eutrophic lakes.
2018年春夏，对长江中下游的26个湖泊进行了研究，以确定氮磷比（TN/TP）的时空特征及其影响因素。从湖泊水源、湖泊深度、悬浮颗粒物浓度和浮游植物水平等方面分析了不同类型湖泊（包括过水湖泊、深水水库和富营养化湖泊）以及不同季节氮磷比的差异。春季平均TN/TP为21.52±14.28，夏季为21.73±23.78。不同类型湖泊的TN/TP差异显著。春季过水湖泊、深水水库和富营养化湖泊的TN/TP比值分别为20.41±9.25、40.97±33.37和14.38±7.40，夏季分别为22.62±6.48、96.38±45.91和10.91±4.44。过水湖泊和深水水库的TN/TP在夏季显著增加，而富营养化湖泊的TN/TP则显著下降，这表明TN/TP变化与湖泊营养状态密切相关。湖泊和水库中营养物质的来源影响TN/TP。湖泊和水库的TN/TP在春季和夏季均与湖泊深度显著相关，表明湖泊深度是影响氮磷比的关键因素。此外，在绝对营养浓度较高的富营养化湖泊中，TN/TP对浮游植物的影响较小，而在绝对营养浓度较低的深水湖泊中，TN/TP可以决定受磷限制的浮游植物的生长。因此，长江中下游湖泊的治理策略应优先控制磷。可以采用局部挖掘、控制面源污染、清淤和改变渔业生产方式等措施来改善富营养化湖泊的生态质量。
