作 者：
徐栋;胡胜华;周巧红;张丽萍;徐恒力;吴振斌
单 位：
中国地质大学环境学院;中国科学院水生生物研究所
关键词：
月湖;硅藻;生物硅;总有机质;沉积速率;水质变化
摘 要：
采用活塞取样器采集了月湖湖中央2处钻孔沉积物,分析了其中硅藻种类与密度的垂直变化,同时采用210Pb/137Cs推测沉积物的沉积速率,并进行了总有机质、生物硅含量分析,以了解月湖各个不同年代的水质变化。结果表明,2个柱状沉积物中硅藻的优势属为:小环藻属、直链藻属、舟形藻属、Cyclostephanos属。Z-1钻孔优势种为:梅尼小环藻、颗粒直链藻、Navicula porifera、Cyclostephanos tholifomis。Z-2钻孔中优势种为:梅尼小环藻、颗粒直链藻、舟形藻、Cyclostephanos invisitatus。就硅藻密度而言,总趋势是上层最多,平均7.14×105～58.65×105ind·g-1,中层其次,平均0.08×105～13.98×105ind·g-1,下层最少,平均0.24×105～0.64×105ind·g-1。硅藻种类数变化虽然没有明显规律,但种类最少的样品出现在中层,210Pb/137Cs测年数据表明中层为19世纪90年代—20世纪70年代。相关分析表明:Z-1孔生物硅与沉积硅藻密度显著正相关(r=0.933,P=0.021<0.05),总有机质含量与种类数显著负相关(r=-0.972,P=0.005<0.05);Z-2孔生物硅与沉积硅藻密度显著正相关(r=0.985,P=0.002<0.05),沉积硅藻密度与种类数显著负相关(r=-0.933,P=0.021<0.05)。研究结果表明,月湖沉积物中硅藻种类与密度的垂直变化可以反映月湖的富营养演化历程:19世纪60年代—19世纪80年代,月湖水质较好;19世纪90年代—20世纪10年代,月湖开始由贫营养状态向中营养状态转变,为水体富营养化开始发生时间;20世纪20年代—20世纪40年代,月湖水体营养等级持续增加,已富营养化;20世纪50年代—20世纪70年代,周边人口数量急剧上升与污水的直接排放导致月湖水质持续恶化;20世纪80年代至月湖截污前这段时期使月湖最终沦为劣五类水体的湖泊。
译 名：
The Vertical Distribution of Diatoms in the Sediments and Water Quality Change of Moon Lake in Wuhan
作 者：
XU Dong1,2, HU Sheng-hua1,3, ZHOU Qiao-hong1,2, ZHANG Li-ping1,2, XU Heng-li3,WU Zhen-bin1,2 (1.State Key Lab of Fresh Water Ecology and Biotechnology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072, China; 2.Graduate University of Chinese Academy of Sciences, Beijing 100049, China; 3.School of Environmental Studies, China University of Geosciences, Wuhan 430074, China)
关键词：
Moon Lake; diatom; BSi; TOM; sedimentation rate; water quality change
摘 要：
This article described and analyzed the vertical distribution of diatom species and their density in two bored sediment cores collected from the center part of the Moon Lake. 210Pb/137Cs analysis was adopted to estimate the sedimentary rate of these two cores; The content analysis of TOM and BSi was conducted to find out the water quality change during different periods in the Moon Lake. The result indicated that the dominant genera in two columnar sediment cores were Cyclotella, Aulacoseira, Navicula and Cyclostephanos. The dominant species of Z-1 bored sediment cores were Cyclotella meneghiniana, Aulacoseira granulata, Navicula porifera and Cyclostephanos tholifomis, the dominant species of Z-2 bored sediment cores were Cyclotella meneghiniana, Aulacoseira granulata, Navicula sp. and Cyclostephanos invisitatus. The diatom density in the two cores shares similar trends:the highest density existed in the upper layer, with an average range of 7.14×105～ 58.65×105 individuals·g-1, which follwed by the intermediate layer presenting an average range of 0.08×105～13.98×105 individuals·g-1, and the lowest density was in the bottom layer, with an average range of 0.24×105～0.64×105 individuals·g-1. No obvious regular pattern was found for the change of diatom species number in either core; However, the lowest species number was in the middle layer of the two sediment cores,which corresponded to the periods between the 1890′s and the 1970′s according to 210Pb/137Cs analysis. The result of correlational analysis showed that in Z-1 bored sediment core, the Bsi density was positively correlated with sediment diatom density(r=0.933, P=0.021<0.05), and the TOM content was negatively correlated with diatom species numbe(rr=-0.972, P=0.005<0.05); In Z-2 bored sediment core, the BSi density was positively correlated with sediment diatom density(r=0.985, P=0.002<0.05), and the TOM content was negatively correlated with diatom species numbe(rr=-0.933, P=0.021<0.05). The research result indicated that the vertical distribution of diatom species and their density could be used to trace eutrophication evolution course of the Moon Lake as follows:from the 1860′s to the 1880′s, the Moon Lake water quality was good; from the 1890′s to the 1910′s, the Moon Lake started its transformation from the poor nutrition condition to a medium condition, it was the beginning of water eutrophication; From the 1920′s to the 1940′s, the water nutrition level kept increasing, leading to a eutrophic condition. Due to the sharp rise of the surrounding population and the direct discharge of sewage, the water quality kept deteriorating from the 1950′s to the 1970′s. After that time, the Moon Lake was finally degenarated among the list of water of the worst five kinds of water quality, till before its recent pollutant truncation.
