星云湖季节性水质变化及影响因素

Abstract

依据实地监测数据，本文分别对旱季和雨季末星云湖水体在垂向和空间分布上的水质变化特征进行了分析，探讨了季节性水量变化对星云湖水质的影响。监测结果显示：星云湖丰水期水质空间差异较小，枯水期水质空间差异较大，主要表现在丰水期溶解氧含量高于枯水期。同时，丰水期水体的比电导明显高于枯水期。星云湖水体的pH值在8.9~9.4之间变化，且有枯水期高于丰水期的特征。在垂向上，星云湖丰水期水温、pH值与溶解氧含量具有相似变化趋势，整体上均随深度的增加而呈现下降的变化，这可能与浮游藻类的呼吸作用有关；丰水期水体中叶绿素含量在整个湖泊较低且趋于一致，而枯水期具有由表层向下增高的变化。营养盐分析结果显示，丰水期的总磷(TP)含量平均为0.43~0.48 mg/L，枯水期平均为0.29~0.39 mg/L；而丰水期的总氮(TN)含量平均为2.1557~2.5225 mg/L，枯水期1.9388~2.875 mg/L，指示丰水期河流物质输入作用明显增加，人类活动影响明显增强。计算分析结果显示，星云湖水体全湖全年为重富营养水平，且具有枯水期水质富营养水平南部 >中部 > 北部水体、底层 > 中层 > 表层水体、丰水期北部 > 南部 > 中部水体，中层 > 底层 > 表层水体的特点。认识这些特点及时空变化规律，对于有的放矢、高效的开展星云湖富营养化治理具有一定的指导作用。 Based on field monitoring data, the characteristics of water quality changes, in both vertical and spatial distributions in the end of dry and wet seasons in Xingyun Lake were analyzed. The monitoring data shows that the water temperature has seasonal changes and on the vertical profile, the water temperature almost always below 1 m in depth. In wet season, the lake water mixture condition enhanced, and the water quality shows slight changes in spatial pattern, but it displays a significant difference in dry season. In vertical profile, the pH value of lake water shows a high uniformity from the surface to 7 m in depth, with an average value of 8.9~9.4. And it shows that a higher value in wet than in dry season. The chlorophyll content in Xingyun Lake shows a weak seasonal change in wet season, but the content increases with the increasing of water depth in dry season. The dissolved oxygen content is higher in wet season than that in dry season. The SpCond is significantly higher in wet season than that in dry season. We found that the water temperature, pH value and dissolved oxygen content possess a similar change tendency in vertical profile. Our analysis results reveal that the average TP content in the wet season is 0.43~0.48 mg/L, while that in dry season is 0.29~0.39 mg/L. The average TN content is 2.16~2.52 mg/L in wet seasons, and 1.94~2.88 mg/L in dry seasons, showing the TP and TN input increased significantly in the wet season. The calculation results demonstrated that the whole lake possess a heavy nutrient level, and the nutrient level distribute a pattern of in the south > in the central > in the north, the bottom > the surface > the middle in dry season, and the north > the south > the central, the middle > the bottom > the surface in wet season.