长潭水库沉积物色素剖面分布及其环境意义

通过对长潭水库沉积物柱芯剖面色素、有机质、总氮和总磷的分析,结合现状水生态监测数据和近50年气候变化数据,揭示了长潭水库营养状态演替及初级生产力变化过程,探讨了人类活动和气候变化对长潭水库初级生产力和藻类演替的驱动作用.结果表明:长潭水库营养状态经历了稳定期、缓慢增长期和快速增长期3个阶段演替过程;沉积物色素剖面浓度也呈现3个阶段上升趋势,藻类由甲藻、硅藻为优势种逐渐演化为蓝藻、绿藻为优势种.外源氮磷输入增加和建库导致的水动力条件变化驱动了长潭水库初级生产力的增加和藻类种群的演替;近50年气候变化加速了水库藻类群落的演替,藻类的优势种演变为对温度敏感的蓝藻拉式拟柱孢藻.本文研究结果可为历史水生态资料缺乏水库的水生态演替识别和生态安全评估提供可借鉴的方法支撑.

Profile distribution of sedimentary pigments and its environmental significance in Changtan Reservoir

Profile distribution of pigments, organic matter, total nitrogen and total phosphorus were investigated in sediment cores of Changtan Reservoir. Combined with current water ecological monitoring data and climate change data for the last 50 years, the trophic state succession and primary productivity change process were revealed. The effects of human activities and climate change on primary productivity and algae succession have been discussed. The trophic state has experienced stable, slow increase and rapid increase stages. The variation trend of sediment pigments was consistent with trophic state. The predominant species of algae gradually evolved from dinoflagellates and diatoms into cyanobacteria and green algae. The change of hydrodynamic conditions due to dam construction and the growth of N and P input result in the increase of primary productivity and the succession of algae community. In the recent 50 years, climate change accelerated the succession of algae community, and dominant species of algae evolved into temperature-sensitive Cylindrospermopsis raciborskii. This study can provide a reference for the identification of water ecological succession and ecological security assessment in the reservoir without water ecological data.