轮叶黑藻(Hydrilla verticillata)对沉积物-水界面微观剖面理化参数的影响

Effects of Hydrilla verticillata on physical and chemical variables of the microprofiles at sediment-water interface

水生植物是湖泊生态系统的重要组成部分,沉积物-水界面是湖泊生态系统中营养盐循环的重要界面,因而研究水生植物对沉积物-水界面微观剖面的影响具有重要意义.本文利用轮叶黑藻作为研究对象,研究了来自于香溪河、太湖和东湖3个样点的沉积物及上覆水中N、P等理化性质,并利用微电极研究轮叶黑藻对3种沉积物-水界面微观剖面是否有影响.实验结果表明:轮叶黑藻生长迅速.增长率因沉积物不同而不同,有一定的耐污能力;轮叶黑藻使水体和沉积物中总氮、总磷含量减少,对水体和底泥有一定的净化作用;轮叶黑藻可使水体溶解氧升高,并使沉积物有氧层厚度增加,改变沉积物的氧化还原电位;轮叶黑藻可能改变了根际微环境中微生物的数量和种类,而使沉积物和上覆水中的pH、N2O和H2S等发生变化.

Aquatic plants is an important component in lake ecosystem and sediment-water interface is one of the most important in- terfaces in nutrient cycle. We studied the effects of the contents of N, P etc. in sediments and their overlying water at three differ- ent sampling sites in Xiangxi River, Lake Taihu and Lake Donghu, and microelectrodes are applied in this study to investigate the vertical section by the effect of H. verticillata. The results show that H. vertlcillata grows quiekly in different sediments. The growth rates of 1,1. verticillata in different types of sediments are different, and H. verticillata has certain tolerance to pollutants. Secondly, H. verticillata has certain influence on both sediments and the overlying water, such as lowering down the contents of TN and TP and so as to purify water and lake bottom sediments. Thirdly, 11. verticillata could increase the content of oxygen in water and the thickness of the aerobic layer, and change oxidation-reduction potential. Fourthly, H. verticillata may change the number and species of microbes in microenvimnment in sediments, and then change the contents and/or levels of pH, N2 O, H2 S etc. in overlying water and sediments.