滇池流域沉水植物衰退和消失驱动因子的研究

Study on the Driving Factors for the Decline and Disappearance of Submerged Macrophytes in Dianchi Lake Basin

为了研究滇池流域沉水植物衰退和消失的驱动因子,该文通过室内控制培养沉水植物黑藻、金鱼藻和篦齿眼子菜,结合沉水植物野外调查数据、水质监测数据和相关数理统计分析结果,定量分析导致沉水植物死亡衰退的驱动因子及其浓度阈值。研究结果表明氨氮是驱动沉水植物分布和群落结构变化的主导因子,氨氮与沉水植物种类的相关性最大,且呈负相关。高浓度的氨氮导致沉水植物黑藻、金鱼藻和篦齿眼子菜死亡,且p H值升高时导致沉水植物死亡的氨氮浓度阈值降低。随着p H值从7升至8.5,导致黑藻死亡的氨氮浓度最低值从12 mg/L下降到2 mg/L,且导致黑藻全部死亡的氨氮浓度最低值从高于16 mg/L下降至6 mg/L,导致金鱼藻死亡的氨氮浓度最低值从高于16 mg/L下降到3 mg/L,导致篦齿眼子菜死亡的氨氮浓度最低值从高于16 mg/L下降到8 mg/L,即氨氮和p H的协同作用加快了沉水植物死亡衰退的速率。因此,氨氮和p H的协同作用是沉水植物的衰退和消失的驱动因素,且p H值越高,驱动作用越明显。

To study the driving factors for the decline and disappearance of submerged macrophytes in Dianchi Lake basin,the driving factors leading to the decline and disappearance of submerged macrophytes and its concentration threshold were quantitatively analyzed, through cultivating submerged macrophytes（Hydrilla verticillata, Ceratophyllum demersum and Potamogeton pectinatus） under the condition of indoor control and combining with field investigation data of submerged macrophytes, water quality monitoring data and related mathematical statistics analysis results. The results showed that ammonia nitrogen was the dominant factor driving the changes of distribution and community structure of submerged macrophytes, and the correlation between ammonia nitrogen and submerged macrophytes was the highest, and was negatively correlated. The experiments showed that the high concentrations of ammonia nitrogen led to the death of Hydrilla verticillata, Ceratophyllum demersum and Potamogeton pectinatus, and the concentration threshold of ammonia nitrogend resulting in the deaths of submerged macrophytes was reduced when the pH increased. As the pH rises from 7 to 8.5, the lowest ammonia nitrogen concentration resulting in the death of Hydrilla verticillata is reduced from 12 mg/L to 2 mg/L, and the lowest ammonia nitrogen concentration resulting in the all death of Hydrilla verticillata is reduced from more than 16 mg/L to 6 mg/L, the lowest ammonia nitrogen concentration resulting in the deaths of Ceratophyllum demersum is reduced from more than 16 mg/L to 3 mg/L, and the lowest ammonia nitrogen concentration resulting in the deaths of Potamogeton pectinatus is reduced from more than 16 mg/L to 8 mg/L.That was, the synergistic effect of ammonia nitrogen and pH value accelerated the death rate of submerged macrophytes. Therefore, the synergistic effect of ammonia nitrogen and pH is driving factors for the decline and disappearance of submerged macrophytes, and the higher pH value, the more obvious the driving effect.