不同水库调度期小江回水区营养盐与叶绿素 a 的垂向分布特征

【摘要】为探讨库区水位调度下小江回水区营养盐浓度和叶绿素a浓度的垂向动态及其相互关系,于2013年4月—2013年12月在小江高阳平湖进行分层跟踪监测。结果表明:研究期间叶绿素a浓度和营养盐浓度分布特征受水位调节的影响明显。表层叶绿素a含量在泄水和蓄水过程中出现了峰值,第1次峰值出现时爆发严重的蓝藻水华。中层叶绿素a在低水位期较高。营养盐浓度随时间变化与水位波动一致,3种磷(TP,DTP,SRP)和TN、NO-3-N含量高水位期高于低水位期。此外,高水位期表、中、低层营养盐浓度没有明显差异,而低水位和泄蓄水期,营养盐浓度垂向变化从表层到底层逐渐增大。并且表层叶绿素a与营养盐之间的关系与中层不同。说明,水位变化不仅影响回水区营养盐浓度,还对营养盐浓度和叶绿素a浓度的垂向分布及其相互关系有影响。

【英文摘要】The nutritive salt and chlorophyll a content in different water layers of Gaoyangping Lake in Xiaojiang backwater area was monitored from April,2013 to December,2013 to discuss vertical dynamic and correlation of nutritive salt and chlorophyll a in Xiaojiang backwater area under water level regulation of Three Gorges Reservoir. The results showed that the distribution feature of nutritive salt and chlorophyll a is influenced by water level regulation significantly.Chlorophyll a in surface water layer appears at peak values during water release and water storage process and severe Cyanobacterial bloom breaks out at first peak value.Chlorophyll a content in middle water layer is higher during the low water level period.Time-varying nutritive salt accords with water level fluctuation and three P (TP,DTP and SRP),TN and NO-3-N content during the high water level period is higher than during the low water level period.In addition,nutritive salt concentration in surface,middle and bottom water layers is no significant difference during high water level period but vertical variation of nutritive salt gradually increases from surface water layer to bottom water layer and the correlation between chlorophyll a and nutritive salt in surface water layer is difference with middle water layer,which indicates that variation of water level not only influences nutritive salt concentration in the backwater area,but also influences vertical distribution and mutual relation of nutritive salt and chlorophyll a.