近70年来梁子湖水生态环境演变

EVOLUTION OF THE WATER ECOLOGICAL ENVIRONMENT OF LIANGZI LAKE IN THE PAST 70 YEARS

  • 摘要: 文章结合文献资料以及监测数据, 对梁子湖水生态环境的演变过程进行了系统梳理。分析表明, 江湖阻隔及闸坝的人为调控改变了梁子湖原有的水文节律。20世纪80年代以前, 梁子湖水质良好; 1986—2004年期间水质年季、年内波动显著, 超标时有发生; 2005—2010年, 水质有所改善, 但自2010以来, 梁子湖富营养化趋势明显, 并已由贫营养演变为中营养-轻度富营养的状态。水生态系统退化趋势明显, 浮游生物及底栖动物优势物种由清洁种转变为耐污种, 夏季蓝藻水华风险增高, 软体动物大量消失, 沉水植物衰退严重, 鱼类物种数减少且小型化趋势明显。水文节律的破坏、污染物的累积、渔业生产活动的影响及洪水导致的持续高水位等是驱动梁子湖水生态环境演变的主要因素。梁子湖水生态环境治理需从污染源控制、生境改善、鱼类种群结构优化等几个方面综合考虑、长远规划, 最终恢复梁子湖的清水稳定状态。

     

    Abstract: This work combines literature findings with recent monitoring data of the author's group to elucidate the evolutionary process of the aquatic environment and ecosystem in Liangzi Lake. Analysis shows that disconnecting of the rivers and lakes, as well as the artificial water level regulation by gates and dams, have changed the original hydrological rhythm of Liangzi Lake. Since 2005, a pronounced trend towards eutrophication has been observed, with Liangzi Lake transitioning from an oligotrophic state to a mesotrophic-mild eutrophic state. While external pollution has been partially controlled, internal pollution release appears to be a significant contributor to water quality deterioration. The degradation of aquatic ecosystems is observed, characterized by a shift in dominant planktons and zoobenthos species towards those tolerant to pollution. In summer, the risk of cyanobacterial bloom increases. Mollusks nearly disappear, the decline of submerged plants is severe, and the number of fish species decreases and showed a trend of miniaturization. The accumulation of pollutants input from the watershed, disruption of hydrological rhythms, fishing production activities, and continuous high-water levels caused by floods are key factors driving the evolution of the aquatic ecological environment in Liangzi Lake. Effective remediation of Liangzi Lake requires comprehensive consideration and long-term planning from several aspects including pollutant control, habitat improvement, and optimization of fish community structure, ultimately restoring Liangzi Lake to its original clear water and submerged macrophyte dominated state.

     

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