【作者】 黄沛生；

【导师】 刘正文；

【作者基本信息】 暨南大学 ， 环境科学， 2005， 硕士

【摘要】 在浅水湖泊生态系统研究中,内源负荷一直受到广泛关注,其主要来源于湖泊沉积物中。因水力扰动引起的沉积物再悬浮是内源释放的主要方式,研究因沉积物再悬浮而引起的内源负荷对了解湖泊生态系统的演化具有极其重要的意义。由于实际条件下环境复杂多变,研究沉积物的再悬浮涉及到风速、风向、湖泊的理化因素和生物因素等各种条件,故进行沉积物再悬浮的野外原位试验并估算沉积物再悬浮引起的营养盐的释放一向是个难题。本研究是定量估算因沉积物再悬浮而引起的湖泊内源释放的初步尝试,并对因抑制沉积物再悬浮而引起的水体氮、磷营养盐浓度的变化进行探讨。 试验结果发现,Gasith方法测定沉积物再悬浮速率可良好地应用在太湖;太湖消浪工程对沉积物的再悬浮有良好的抑制作用。作为一个典型的大型浅水湖泊,太湖受到强烈的风生浪作用,从而使大量的沉积物因再悬浮而进入水体。试验期间在无消浪措施的敞水带（E区）,沉积物的再悬浮速率为804.49gdw m^-2d^1-(293.64kg m^-2 a^-1),受水泥桩消浪带保护的B区其沉积物再悬浮速率为293.27g dw m^-2 d^-1(107.05kg m^-2 a^-1),是无消浪措施的敞水带（E区）的36.50%;受水泥桩消浪带和软围隔保护的A区其沉积物再悬浮速率为134.67g dw m^-2 d^-1(49.15kg m^-2 a^-1),是无消浪措施的敞水带（E区）的16.75%。随着沉积物的再悬浮,E区每天每平方米进入水体的总氮有1664.29mg,总磷有633.06mg,受消浪工程保护的区域其氮再悬浮速率只有E区的43.33%（B区）和23.57%（A区）;其磷再悬浮速率只有E区的41.27%（B区）和19.51%（A区）。 沉积物再悬浮速率直接影响水体悬浮物浓度,因再悬浮而产生的悬浮物占总悬浮物的79.67%到97.23%之间,平均为86.56%:悬浮物浓度与水体总氮、总磷浓度有良好的正相关关系,说明水体悬浮物浓度控制了水体的总氮总磷浓度。故而控制沉积物的再悬浮速率,有利于降低水体的悬浮物浓度,从而降低水体的总氮总磷浓度。悬浮物浓度与总溶解磷浓度呈负线性相关关系,说明悬浮物有吸收或释放水体溶解磷的功能,取决于悬浮物的磷饱和度。更多还原

【Abstract】 Inner-source loading was a key factor to influence the ecosystem of shallow lake, it played an important role after the outer-source loading was removed. Sediment resuspension was the major method of inner-source release induced by wind or fish predation. In this study, we try to quality the effect of an ecological engineering on sediment resuspension with sediment trap, seston and surface sediment, and discuss the influence of sediment resuspension on nutrient structue in water column. The results suggest that the ecological engineering can reduced the sediment resuspension effectively. As a classical large shallow lake, Taihu Lake is suffered from the wind-induced wave and sediment is brought into water column. During the study period, the sediment resuspension rate was 804.49 g dw m-2 d-1 (293.64 kg m-2 a-1) in the pelagic zone(E zone), while in B zone (protected by wave-eliminated engineering) and A zone (protected by wave-eliminated engineering and enclosure) the sediment resuspension ratewas 293.27 g dw m-2 d-1 (107.05 kg m-2 a-1, 36.50% of E zone) and 134.67 g dw m-2 d-1 (49.15 kg m-2 a-1, 16.75% of E zone) . With resuspension 1664.29 mg N m-2 d-1 and 633.06mg P m-2 d-1 was brought into water column in E zone. In B zone the corresponding numbers was 721.08 mg and 261.26 mg respectively. In A zone the corresponding numbers was 392.10 mg and 123.52 mg respectively.The seston concentration was controlled by sediment resuspension and had positive relationship with TN and TP concentration, which meant that the reduction of sediment resuspension rate resulted in the reduction of seston concentration and consequently reduced the TN and TP concentration in water column. Resuspended particles can either adsorb phosphorus from the water or release it, depending on their P saturation level, so the TDP concentration had negative relationship with the seston concentration.更多还原