| 太湖不同介质电导率时空变化特征 |
| 摘要点击 1749 全文点击 593 投稿时间：2019-04-22 修订日期：2019-05-10 |
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| 中文关键词 太湖 电导率 时空变化 水体 沉积物 孔隙水 |
| 英文关键词 Taihu Lake conductivity temporal and spatial variation water sediment pore water |
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| 中文摘要 |
| 电导率是表征水体溶解性固体物质或盐度的重要参数，也是水体常规监测参数之一.为揭示太湖不同介质电导率的时空变化特征，对太湖水体水质历史数据（1980~2009年）以及近10年来野外监测数据（2009~2018年）进行统计分析.结果表明，近40年来太湖水体电导率呈显著上升趋势，并在1996~1997年发生突变.太湖水体电导率由1980~1996年的（239.43±70.60）μS·cm-1增长到目前的（477.31±23.47）μS·cm-1，年均增长率10.40 μS·（cm·a）-1；空间上，西北湖区水体电导率显著高于东南湖区；水体电导率变化以主要离子变化为主导，氮营养盐的贡献基本可忽略；流域人类活动是引起水体电导率变化的主要因素.此外，太湖水体电导率受季节性径流的影响更为显著.与湖水电导率变化规律相比，西北湖区表层沉积物、孔隙水（0~10 cm）电导率均低于东南湖区，深层（>10 cm）则相反.剖面上，西北湖区表层沉积物、孔隙水（0~10 cm）电导率和深层（>10 cm）无显著差异，但东南湖区表层沉积物、孔隙水（0~10 cm）电导率高于深层（>10 cm）.沉积物电导率与有机质呈显著正相关（P<0.01），与pH呈负相关（P<0.05），表明有机质对金属离子活化迁移具有明显的促进作用，而酸性环境下更有利于离子的活化.对不同介质间电导率分析发现，表层沉积物和孔隙水（0~10 cm）电导率均与上覆水电导率呈显著正相关（P<0.01），而深层（>10 cm）沉积物及孔隙水电导率与上覆水电导率没有相关性，表明表层沉积物和孔隙水（0~10 cm）对上覆水电导率有明显影响.此外，整个剖面上（0~50 cm）沉积物电导率和孔隙水电导率呈显著正相关（P<0.01），说明沉积物和孔隙水之间进行着比较充分的离子迁移交换，两者之间的相互影响总体上高于对上覆水的影响. |
| 英文摘要 |
| Conductivity is an important parameter for characterizing dissolved solids and salinity in water, and is also one of the routinely measured parameters in water quality monitoring. To reveal temporal and spatial variations in conductivity in different media in Taihu Lake, historical data (1980-2009) were collected and field monitoring data (2009-2018) were analyzed. The results indicated that water conductivity in Taihu Lake has shown a significant increasing trend over the past 40 years and diverged in 1996-1997. Conductivity values increased from (239.43±70.60)μS·cm-1 in the period 1980-1996 to(477.31±23.47)μS·cm-1 in the present day, with an average annual increase of 10.40 μS·(cm·a)-1. Spatially, the conductivity of water in the northwest part of the lake was significantly higher than the southeast part. These changes in conductivity are dominated by changes in major ions, and the contribution of nitrogen was essentially negligible. Human activities in the basin have been the main factors causing changes in water conductivity. In addition, conductivity is significantly affected by seasonal runoff. Compared with the water, the conductivity of the surface sediments and pore water (0-10 cm) in the northwest part of the lake were lower than in the southeast part, while this trend was opposite in the deeper sediments (>10 cm). The conductivity of the sediment and pore water were no different between surface (0-10 cm) and deeper (>10 cm) sediments in the northwest lake, while these were higher in the surface sediments in the southeast part of the lake. Sediment conductivity was positively correlated with organic matter (P<0.01) and was negatively correlated with pH (P<0.05). This indicated that organic matter promotes the activation and migration of metal ions, which are more activated under acidic conditions. We found that conductivity in the surface sediments and pore water (0-10 cm) were significantly positively correlated with conductivity in the overlying water (P<0.01). In contrast, the conductivity of overlying water was not correlated with the conductivity of deeper sediments and pore water (>10 cm). These patterns indicated that surface sediments and pore water have a significant effect on the conductivity of overlying waters. In addition, there was a significant positive correlation between the conductivity of sediment and pore water (P<0.01) within the entire sedimentary section (0-50 cm), indicating efficiency ion-exchange between the two. The interaction between sediment and pore water was generally stronger than their interaction with the overlying water. |
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