蒙新高原岱海夏季叶绿素a浓度空间分布及影响因子

基于2019年夏季(8月)对岱海水样的实测数据分析,通过运用克里金插值、相关性分析、多元线性逐步回归、主成分分析方法,探究了叶绿素a(Chl.a)的空间分布特征及其与水环境因子的相关关系,并讨论了相应的防治措施。研究显示:Chl.a空间分布呈现由岸边向湖心递减的趋势,总氮(TN)、总磷(TP)、氨氮(NH₃-N)、硝态氮(NO^-₃-N)、正磷酸盐(PO^3-₄-P)空间分布特征与Chl.a空间分布特征相近,采样期内岱海湖局部区域水质状况已达到富营养状态;Chl.a与浊度(Turbidity)、TP、TN、悬浮物(SS)、pH、NO^-₃-N、NH₃-N、PO^3-₄-P、蓝绿藻丰度(CYANO)呈极显著正相关,与溶解氧(DO)呈显著负相关,与电导率(Cond.)呈正相关、与氮磷比(TN/TP)呈负相关;各湖区Chl.a与环境因子相关关系不同,全湖逐步线性回归方程为Y_Chl.a=-21.42+8.658X_pH-0.865X_DO+0.779X_NH3-N+0.699X_Turbidity+0.502X_CYANO;岱海不同湖区因子对Chl.a浓度的影响存在差异,各湖区Chl.a与环境因子相关关系不同,通过岱海与我国其他湖泊Chl.a与环境因子的相关性关系对比分析,湖泊地理属性差异及营养物质输入浓度是影响Chl.a变化的重要因素;本研究岱海的TN/TP平均值为12.23,说明夏季岱海湖Chl.a变化为氮磷共同限制。

Spatial distribution characteristics of chlorophyll-a concentration in summer and its influencing factors in Lake Daihai of Mengxin Plateau

Kriging interpolation, correlation analysis, multiple linear step-to-step regression and principal component analysis was used to analyze the water sample data in Lake Daihai in August 2019. The results showed that the concentration of chlorophyll-a (Chl.a) decreased from the shore to the center of the lake. The spatial distribution characteristics of totoal nitrogen(TN), total phosphorus(TP), ammonia nitrogen(NH₃-N), nitrate nitrogen(NO^-₃-N) and orthophosphate (PO^3-₄-P) were similar to those of Chl.a, and the water quality of some region in Lake Daihai had reached heavy eutrophication during the sampling period; Chl.a was positively correlated with turbidity, TP, TN, suspended solids (SS), pH, NO^-₃-N, NH₃-N, PO^3-₄-P and blue-green algae abundance (CYANO), significantly negatively correlated with dissolved oxygen (DO), positively correlated with electrical conductivity(Cond.), and negatively correlated with phosphorus-nitrogen ratio(TN/TP). The correlations between Chl.a and environmental factors were different in the different lake areas, and the linear regression equation in Lake Daihai was Y_Chl.a=-21.42+8.658X_pH-0.865X_DO+0.779X_NH3-N+0.699X_Turbidity+0.502X_CYANO. There were differences in the effects of environmental factors on Chl.a content in different lake zones, and the correlation between Chl.a and environmental factors in each lake zone was also different. By comparing the correlation between Chl.a and environmental factors in Lake Daihai with other lakes in China, we found that the differences in the properties of various lakes and the nutrient contents were important factors in affecting Chl.a. In this study, the average TN/TP was 12.23 in Lake Daihai, as indicated that the growth of Chl.a was co-limited by nitrogen and phosphorus in summer.