武汉东湖近代沉积物中总氮、总磷与生物硅沉积与营养演化的动态过程

摘要

The Donghu Lake, being at a high eutrophic status due to eutrophication in Wuhan, was choosen as the study area, where sediment samples were collected and analyzed for the contents of total nitrogen (TN), total phosphorus (TP) and biogenic silica (Bsi) in the 4 sub-lakes. The results showed that: in comparison with the deposition rate of the Donghu Lake (about 0.33cm/a), in the bottom of 41 ~ 50 cm (1860 ~ 1890a) and 31 - 40 cm (1890a - 1920a), TN, TP and Bsi were the basic natural lake sediments in the 4 sub-lakes. In the middle of 21 ~ 30 cm (1920a ~ 1950a), while human activities had increased, the deposition changed. In the surface sediments of 0-10 cm (1980a ~ 2010a), and 11 ~ 20 cm (1950a - 1980a), the depositions of TN, TP and Bsi were generally increased. The comparative study on the sediments such as TN, TP and Bsi in the 4 sub-lakes of the Donghu Lake showed that: increasing human activities on the Donghu Lake led to more nitrogen and phosphorus emissions, promoted the growth of diatoms and consumption of silicon in the Donghu Lake. There was also a significant difference in the deposition of nitrogen, phosphorus and silicon among the 4 different sub-lakes of the Donghu Lake, which might be related to the different impacts of human activities.%选择富营养化程度较高的武汉东湖作为研究对象,于2011年对其中4个子湖湖心的沉积物进行了采集,并分析了沉积物中总氮、总磷与生物硅含量.结果表明:对照东湖沉积速率(约0.33 cm·a-1),在底层41 ～50 cm(1860-1890年)与31～40 cm(1890-1920年),东湖4处子湖氮、磷、硅基本为湖泊自然沉积；在中层21～30cm(1920-1950年),人类活动有所增强,沉积有所变化；表层沉积物0～ 10 cm(1980-2010年)、11～20cm(1950-1980年)中氮、磷、硅沉积普遍上升,这一时期对应着东湖人类干扰活动的普遍增加.对东湖4个子湖的沉积物氮、磷与硅的对比研究表明:人类活动增加了对东湖氮、磷的排放,促进了东湖硅藻的生长及硅的消耗,东湖不同子湖之间氮、磷、硅的沉积存在着明显差异,这可能与人类活动的影响差异有关.