三峡库区大宁河沉积物营养盐时空分布及其与叶绿素的相关性分析

为研究大宁河底泥营养盐时空分布与藻细胞分布的关系,本研究在大宁河选择4个代表性的取样点:菜子坝、白水河、双龙和大昌,利用垂直重力采泥器,按照2 cm厚度分层选取底泥,检测底泥中总氮,氨氮、硝态氮、亚硝态氮、总磷、无机磷、有机磷和叶绿素的垂向分布,分析叶绿素与营养盐的相关性.结果表明,菜子坝底泥0.0~2.0 cm总氮浓度最高,白水河底泥2.0~4.0 cm的总氮浓度最高;菜子坝底泥2.0~4.0 cm氨氮浓度最高,1和2月白水河底泥4.0~6.0 cm浓度较高;硝酸氮和亚硝酸氮(除3月)在菜子坝底泥2.0~4.0 cm浓度最高;氨氮、硝酸氮和亚硝酸氮浓度在同一个采样点底泥4.0 cm以下分层差异不显著;白水河底泥总磷0.0~6.0 cm呈增加趋势,菜子坝底泥表层的总磷和无机磷的浓度显著高于其它分层,而且每一分层中总磷、无机磷浓度都高于其他3个取样点相应的分层;有机磷在菜子坝和大昌的浓度高于白水河和双龙的浓度,但是同一采样点底泥不同分层的有机磷浓度差异不显著;同一深层底泥中的叶绿素a浓度在大昌最高,其次是白水河,再次菜子坝,双龙处的叶绿素浓度最低;只有1月在大昌取样点处无机磷和叶绿素a的浓度显著正相关,相关系数为0.87,底泥中的营养盐不是影响底泥藻细胞分布的主要影响因素.

Temporal and Spatial Distribution of Nutrients in Daning River Sediments and Their Correlations with Chlorophyll in the Three Gorges Reservoir Area

In order to understand the temporal and spatial distribution of nutrients in Daning river sediments and to investigate the relationship between nutrients and algal cells, samples were selected from 4 typical sampling sites, i.e. Caizi Dam, Baishui River, Shuanglong and Dachang. Vertical gravity mud samplers were used to collect the sediments from different layers within 20 cm in increment of 2 cm. Vertical distributions of TN, NH₄⁺-N, NO₃^--N, NO₂^--N, TP, inorganic P and organic P in sediments of different sampling sites were investigated. And so was the vertical distribution of chlorophyll. Moreover, the correlation between chlorophyll and the nutrients was analyzed. Results showed that the contents of TN were the highest at the depth of 0.0-2.0 cm in the Caizi Dam sediments, and at the depth of 2.0-4.0 cm in the Baishui River sediments. The highest NH₄⁺-N content occurred at 2.0-4.0 cm in the Caizi Dam sediments and at 4.0-6.0 cm in the Baishui River in January and February. As to NO₃^--N and NO₂^--N contents, they were the highest at 2.0-4.0 cm in Caizi Dam sediments except March. For NH₄⁺-N, NO₃^--N and NO₂^--N, there was no significant difference under 4.0 cm sediments at the same sampling site. The distribution of TP was increasing from 0.0 to 6.0 cm in Baizi River sediments. But in Caizi Dam sediments TP and inorganic P contents in 0.0-2.0 cm were higher than those of others layers; TP and inorganic P in all different layers of Caizi Dam sediments were greater than those of corresponding layers in other sampling sites' sediments. The contents of organic P at Caizi Dam and Dachang were higher than those of Baishui River and Shuanglong, while the difference of organic P contents was not significant in different sediments layers at the same sampling site. The chlorophyll a contents in Dachang were the highest at every layer comparing to the corresponding layers of others, followed by Baishui River, Caizi Dam, and Shuanglong. Only one significantly positive correlation was observed between the content of inorganic P and chlorophyll a in Dachang site in January, with the correlation coefficient was 0.87.The correlation results implied that nutrients in sediments were not the main factors affecting the distribution of algal cells.