In order to determine the spatial and temporal distribution of eutrophication in Lake Hulun, and to understand the water chemical composition and its impact factors of lake water. The samples were taken in frozen (upper layer of ice, middle layer of ice, lower layer of ice stratified sampling) and unfrozen peried of Hulun Lake and analyzed from 2013 to 2015. Arcgis spatial interpolation,Piper diagram and Gibbs diagram is used to analyze the samples. The results showed that the average concentration of TN and TP in the water of Hulun Lake was 1.318~3.124 mg?L-1, 0.188~0.231 mg?L-1, and in the water of Hulun Lake was 2.148~2.428 mg?L-1, 0.149~0.277 mg?L-1, respectively. The concentrations of TN and TP in Hulun Lake had similar characteristics and the nutrient concentration of water is mainly affected by precipitation and runoff. The Kelulun River and the Wuerxun River had a good dilution influence on the nutrients concentration of the lake. The nutrient concentration distribution in the south part of the lake was higher than that in the north. Among them, the change of nutrient concentration in the sampling area of the Xiao He Kou scenic area (A10), the Wuerxun River into the lake (F9) and the Wudulu fishing ground (I5) was significant with the seasons. TN, TP concentrations in water during the unfrozen period of lake were higher than that in water during the frozen period of lake. The concentrations of TN and TP in the ice layer distribute as followed: upper layer of ice>lower layer of ice>middle layer of ice. The nutrient migration model in different ice layers were used to explain the distribution of nutrients. The main ion composition in Hulun lake was affected by the rock weathering and evaporation. Piper triangular figure showed that the water chemistry type of Hulun Lake was mainly K++Na+-HCO3--CO32--Cl-. The Gibbs diagram showed that the water composition of the Hulun Lake was affected mainly by rock weathering and evaporation. The cations in water were controlled only by evaporation and the anions in water bodies were controlled by evaporation and rock weathering. The NO3- and NO2- concentrations changed significantly with the seasons. The concentration distribution of cation was concentrated and stable, and the anion concentration had significant difference, which may be impacted by human activities.%为明确近年来呼伦湖富营养化特征,同时揭示呼伦湖水化学组成、演化过程及其影响因素,连续3年对呼伦湖冰封期与非冰封期湖水进行采样,对湖冰(上层冰、中层冰、下层冰)进行分层采样,综合运用Arcgis空间插值、Piper三角图、Gibbs图等方法对总氮(TN)、总磷(TP)、阴阳离子在冰体与水体中的分布特征进行对比分析.结果表明,冰封期呼伦湖水体TN、TP平均浓度变化范围分别为1.318~3.124、0.188~0.231 mg?L-1;非冰封期分别为2.148~2.428、0.149~0.277 mg?L-1.呼伦湖水体TN、TP浓度在时空分布上具有相似特征且迁移变化趋势一致,水体营养盐浓度主要受降水与径流影响,克鲁伦河与乌尔逊河等入湖河流对湖水营养盐浓度有良好的稀释作用.水体营养盐浓度分布呈现南部高于北部,且存在着由南向北的迁移变化过程,其中,呼伦湖小河口风景区(A10)、乌尔逊河入湖口(F9)、乌都鲁渔场(I5)采样点营养盐浓度随季节变化显著.同年冰封期水体TN、TP浓度大于冰体浓度,垂直方向上营养盐浓度表现为上层冰>下层冰>中层冰,不同冰层间营养盐迁移模型宏观解释了营养盐分布特征的成因.Piper三角图表明呼伦湖水化学类型以K++Na+-HCO3--CO32--Cl-型为主.Gibbs图显示呼伦湖水体离子组成主要受岩石风化与蒸发作用影响,其中,水体阳离子只受蒸发作用控制,水体阴离子受蒸发作用与岩石风化共同控制.不同时期离子浓度分布特征表明,阳离子浓度分布集中且稳定,阴离子浓度存在显著的周期差异性,其中,NO3-与NO2-浓度随季节变化明显,主要受人类活动影响.
展开▼
