东太湖渔业养殖对沉积物营养盐的影响

Effects of Optimized Fish Farming on the Sediment Nutrients of Eastern Lake Taihu

湖泊渔业是我国淡水渔业的重要组成部分.传统的渔业养殖模式对湖泊生态系统产生了严重的负面影响.近年来,东太湖的围网养殖模式进行了优化调整.本文通过对比东太湖不同区域(养殖网围内、养殖网围外,蟹草养殖区、混养养殖区、恢复区与对照区),不同时间(1、3、4、8与11月),以及沉积物不同深度(0~1 cm与9~10 cm)的理化指标数据,来分析湖泊水产养殖对沉积物理化性质的影响.结果表明,养殖网围内沉积物中总氮、总磷含量略高于网围外;与蟹草养殖区相比,混养养殖区沉积物中总氮、总磷含量更低,造成的污染更小;恢复区生长和分布大量水生植物,对已污染湖泊的生态恢复有一定的帮助;在水生植物生长的旺季,沉积物中总氮、总磷含量最低,说明水生植物能有效控制沉积物中的氮磷.

The farming of lake fisheries is an important part of the freshwater fishery industry in China.However,farming patterns of traditional fisheries maintain serious negative effects on the ecosystem of Eastern Lake Taihu.In recent years,the enclosure culture model of this lake has been optimized.In order to investigate the effects of aquaculture on the sediment properties,samples were collected from different areas of the lake（i.e.within the culture areas,outside the culture areas; from the crab-plant co-culture areas,mixed culture areas,ecological restoration areas,and control areas）,in different months（January,March,April,August,and November）,and at different depths（0-1 cm and 9-10 cm）.The results of this sampling indicates that（1） the concentrations of total nitrogen（TN） and total phosphorus（TP） in the sediments samples collected within the culture areas are slightly higher than samples collected outside the culture areas;（2） compared to the crab-plant co-culture areas,lower concentrations of TN and TP are found in the samples collected from the mixed culture areas;（3） in the ecological restoration areas,aquatic plants exhibit certain positive effects with decreasing concentrations of TN and TP in the sediment.The lowest concentrations of TN and TP are detected in the sediment during the growing season of aquatic plants.