【摘要】 湖泊水体中氮、磷和叶绿素a空间分布特征及其响应关系对辨识水环境质量具有重要意义。尤其对于冰封期典型的水文气候条件,将表现出特殊的环境地球化学行为,冰封期结冰过程使水体不同形态的氮、磷由冰层向水体迁移,导致冰下水体中营养盐浓度、叶绿素a浓度大于冰层,冰下水体污染物浓度增加。为量化不同污染物质在冰-水介质中迁移规律,于2020年1月14日采集乌梁素海12个样点的冰样和冰体,检测了各采样点不同形态氮磷和叶绿素a浓度。结果表明:冰样中高值ρ_（TN） 0.838 mg·L^-1、ρ_{（NH4⁺-N）} 0.109 mg·L^-1、ρ_{（NO3^--N）} 0.347 mg·L^-1分别位于湖心区的Q8采样点和北湖区的J11采样点。TN、NH₄⁺-N、NO₃^--N集中分布在中层冰、下层冰和上层冰,冰下水体中北湖区的ρ_（TN）、ρ_{（NH4⁺-N）}、ρ_{（NO3^--N）}、ρ_{（NO2^--N）}出现高值。在冰样和冰下水体中总磷（TP）和溶解性总磷（DTP）的分布规律均为北湖区最高,南湖区最低。并且TP和DTP集中分布在下冰层。冰样中Chl-a在北湖区、湖心区和南湖区的平均质量浓度分别为2.455、1.407和1.210 mg·L^-1,41.6%采样点的中层冰和下层冰中含有高浓度的Chl-a。冰下水体中Chl-a的质量浓度范围是1.530—12.280mg·L^-1,均值为7.874mg·L^-1。冰封期乌梁素海的氮、磷和叶绿素a集中分布在冰下水体中。线性回归分析表明冰层和冰下水体中不同形态的氮、磷对叶绿素a的响应存在不同程度的差异。研究结果可为乌梁素海进一步的污染治理提供参考和借鉴。更多还原

【Abstract】 The spatial distribution characteristics of nitrogen, phosphorus and chlorophyll-a in lake water and their response relationships are of great significance to identify the quality of water environment. Especially for the typical hydrological and climatic conditions in the ice sealing period, special environmental geochemical behaviors will be displayed. The ice process in ice sealing period makes the nitrogen and phosphorus in different forms migrate from ice layer to water body, which leads to the concentration of nutrient salt and chlorophyll-a in the water body under ice is higher than that of ice layer, and the concentration of pollutants in the water under ice increases. In order to quantify the migration pattern of different pollutants in the ice-water medium,ice samples and ice bodies were collected from 12 sampling points in Lake Ulansuhai on January 14, 2020. And the concentrations of different forms of nitrogen, phosphorus and chlorophyll-a were detected. The results showed that the high values of ρ_（TN） 0.838 mg·L^-1, ρ_{（NH4⁺-N）} 0.109 mg·L^-1 and ρ_{（NO3^--N）} 0.347 mg·L^-1 in ice samples were located at Q8 sampling point in the central of lake and J11 sampling point in the north of lake, respectively. TN, NH₄⁺-N, NO₃^--N were intensively distributed in middle ice, lower ice and upper ice. The concentrations of TN, NH₄⁺-N, NO₃^--N, NO₂^--N were all very high in the north of lake. The distribution trend of total phosphorus（TP） and dissolved total phosphorus（DTP） in the ice sample and subglacial water is the highest in the North Lake area and the lowest in the South Lake area.TP and DTP were concentrated in the lower ice layer. The average concentrations of chlorophyll-a in the North Lake area, the central Lake area and the South Lake area are 2.455 mg·L^-1, 1.407 mg·L^-1 and 1.210 mg·L^-1, respectively. High concentrations of chlorophyll-a were found in the middle layer ice and the lower ice at 41.6% of the sampling sites. The concentration range of chlorophyll-a in subglacial water was 1.530–12.280 mg·L^-1, with an average value of 7.874 mg·L^-1. Nitrogen, phosphorus and chlorophyll-a were concentrated in the subglacial water in Lake Ulansuhai. Linear regression analysis showed that the response of nitrogen and phosphorus in different forms to chlorophyll-a in ice layer and subglacial water was different. The research results can provide reference for further pollution control in Lake Ulansuhai.更多还原