东湖富营养化的成因分析和治理对策.pptx

东湖富营养化的成因分析和治理对策 Eutrophication of Lake Donghu : Cause Analysis and Remedy Strategy 刘 建 康 Jiankang LIU 中科院水生生物研究所 Institute of Hydrobiology, the Chinese Academy of Sciences;Serious eutrophication in Lake Donghu;1．二十年前东湖富营养化的综合评价和氮磷收支 Comprehensive evaluation of Donghu’s eutrophication in the 1980s and its N, P budgets ;Eutrophication of the lake began in the mid-1950s and proceeded rather fast. ;Early 1980s: NO3-N, NO2-N, NH4-N, TN, PO4-P, TP, SiO2 Phytoplankton Average daily primary gross production Biomass Chlorophyll a A comprehensive evaluation of status of eutrophication: on the way of transition from eutrophic to hyper-eutrophic (Cai,1993) ;氮的总输入量: 536 t/a 总负荷量: 19.22g/m2 磷的总输入量: 87.8 t/a 总负荷量: 3.15 g/m2 输入-输出差: 总氮 323.2 t/a （占总输入量60.3%） 总磷 67.7 t/a （占总输入量77.1%） （张水元等，1984） ; Abundance and species composition of phytoplankton in Lake Donghu during 1956－1975, and the dynamics of primary productivity;The average annual total number of phytoplankton was steadily on the increase 1950s: 27-949 ind/ml 1960s: 156-4662 ind/ml 1970s： 1000-35000 ind/ml ;Pronounced change occurred in the species composition of phytoplankton 1956-1957: Pyrrophyta Bacillariophyta 1960s: Cyanophyta Chlorophyta Microcystis Aphanizomenon Anabaena etc. ;Primary productivity of phytoplankton increased rapidly ;Aggravation of exogenic pollution through the discharge of urban household sewage as well as industrial wastewater in an immense amount; The disappearance of aquatic macrophytes reduced the competition for nutrients, causing the luxuriant proliferation of phytoplankton; Dike construction within the lake diminished the exchange of water mass between Guozhenghu area and other lake areas with lower loading of N and P . (Rong et al., 1995) ;The distinction between “fish-stocking” and “intense fish-farming” ;