太湖梅梁湾理化指标分层的空间分布特征

为了解大型浅水湖泊水体理化指标的空间分异特征,在太湖梅梁湾布设62个采样点,垂向分为3层,调查水体中Chla、TN、TDN(溶解性总氮)、TP、TDP(溶解性总磷)的质量浓度及SD(透明度)、DOS(溶解氧饱和度)等水体理化指标,统计分析了夏季太湖水体理化指标空间分布特征及影响因素. 结果表明:①梅梁湾水体理化指标垂向时空变幅不同,垂向相对变幅平均值ρ(TN)为68.0%,ρ(TDN)为40.1%,ρ(TP)为138.0%,ρ(TDP)为35.7%,ρ(Chla)为66.0%,DOS为79.0%,营养盐总量的垂向差异比溶解态大；②平面上,水华堆积区ρ(TN)、ρ(TDN)、ρ(TP)、ρ(TDP)、ρ(Chla)、DOS平均值分别为梅梁湾平均值的4.45、2.45、6.45、4.74、2.08、1.02倍,比垂向差异大；③风场驱动下蓝藻堆积对水体各理化指标空间分布的影响巨大；④ρ(Chla)垂向分层明显,ρ(Chla)的垂向变幅表层0.2m处显著高于下层,可达89.7μg/L. 浅水湖泊的水体理化指标时空变异大,受气象条件、水动力条件等因素的影响,故在监测点位布设及数据分析时,应考虑垂直分层采样、滨岸带采样并详细记录采样条件. 

Spatial Distribution of the Physicochemical Parameter Stratification in Meiliang Bay, Lake Taihu, China

Based on the field data on Aug 27,1in Meiliang Bay, Lake Taihu, China, the spatial distribution and the control factors of physicochemical parameters of water in the shallow lake have been investigated. The results showed that:1) The parameters were different between in different depths. The average of vertical difterent of TN, TDN, TP, TDP, Chla, DOS were 68.0%, 40.1%, 138.0%, 35.7%, 66.0%, 79.0%. The vertical difference of total nutrients was greater than those of the dissolved nutrients (e.g., total nitrogen and total phosphorus); 2) The concentrations of TN, TDN, TP, TDP, Chla, and DOS in the Microcystis bloom region were 4.45times, 2.45times, 6.45times, 4.74times, 2.08times, and 1.02times of the in non-bloom region in Meiliang Bay, respecitvley; 3) The vertical difference of the parameters was strongly influenced by the algal bloom accumulation; 4) The concentration of Chla was strongly stratified. This study suggested that the spatial differences of water parameters in shallow lakes were significant. The extent of difference is strongly related to the weather condition and hydrodynamics. Environmental conditions would be considered when designing the lake survey and analyzing data.