东湖富营养化的成因分析和治理对策

ecosystem
东湖富营养化的成因分析和治理对策
•团头鲂（Megalobrama amblvcephaia
Yih）是草食性鱼类
•Donghu : •
•Blunt snout bream (Megalobrama amblicephala), also known as “Wuchang Fish”, is likewise a grass eater, though less voracious; its stocking in lake is not recommended.
东湖富营养化的成因分析和治理对策
•东湖的富营养化 •开始于五十年代中期，进程颇为快速
。
•Eutrophication of the lake began in the mid-1950s and proceeded rather fast. •
东湖富营养化的成因分析和治理对策
•八十年代初期 •NO3-N, NO2-N, NH4-N, TN, PO4-P, TP, SiO2 •浮游植物: • 日平均初级生产量 生物量 叶绿素a •东湖当时已处于富营养化向超富营养化过渡的阶段（ 蔡庆华，1993）
•（戎克文等，1995 ）
1) Aggravation of exogenic pollution through the discharge of urban household
sewage as well as industrial wastewater in an immense amount;
• N 323.2 t/a （60.3% of total input）
• P 67.7 t/a （77.1% of total input）
•
东（湖富营Z养h化a的成n因g分析e和t治a理l对，策 1984）
• 2．1956-1975年东湖浮游藻类数量和 种类组成情况，和初级生产力的演变
• Abundance and species composition of phytoplankton in Lake Donghu during 1956－ 1975, and the dynamics of primary productivity
失直接削弱了水体自净的能力 • 2）水生大型植物是与浮游植物竞争养料的，前者
的消失使后者能独享养料资源，导致浮游藻类的大 量孳生，反过来通过在养料和光照方面的竞争优势 ，进一步压制水草的恢复
• 1) Aquatic macrophytes play the role of purifying the water quality, their disappearance attenuates directly the self purification capability of the water body.
卵囊没有水草可资附着，卵的孵化率大大降低
• 4）水草也是许多亡的
机率大增，进而影像响到该生态系统的生物多样性
•
。
3) Macrophyte is the substratum on which the adhesive eggs
of many fish, snail, and aquatic insect species are deposited;
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）
•N input:
536 t/a
•Total loading:
19.22g/m2
•P input:
87.8 t/a
•Total loading:
3.15 g/m2
•Difference in input and output:
东湖富营养化的成因分析和治理对策
•鲤鱼（Cyprinus carpio）是生活在水体底层的鱼类
。它以螺蚌等底栖动物为食，习惯在底泥中觅食，动 辄把水搅浑。鲤鱼在泥底中的掘进习性使它易于从围 圈边缘逃逸；鲤鱼的捕捞也比较困难。 •湖泊放养对象中不包括鲤鱼
•The common carp (Cyprinus carpio) is a fish living on the bottom of water body, feeding on benthic animals like snails, clams, and insect larvae. Searching for food in the sediment, the fish is very likely to stir up the bottom deposit and makes the water turbid. It is also difficult to capture.
food
•人 工饲 料
•Artificia l feed
东湖富营养化的成因分析和治理对策
• 4．放养不同种类的鱼给湖泊生态系统 带来的不同影响
• Impacts on lake ecosystems are different when different fish species are stocked
• 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
•Microcystis Aphanizomenon Anabaena
etc.
•（Jao and Zhang，1980）
东湖富营养化的成因分析和治理对策
•浮游藻类初级生产量急剧增加
•
•1963－1990年:最高生产层日产量平均每年增长0.256 mg O2/ 天
•
水柱最高日产量平均每年增长0.243 g O2/m2﹒天
production increased by 0.256 mg O2 per day,
•
Maximum daily production of water column increased by
0.243 g O2/m2 per day.
•
1973-1985: Daily production of water column increased by 0.554 g
东湖富营养化的成因分析和治理对策
•不同养殖类型的划分
Different types of fish culture
•管理水平 •投入和回收
•抗病能力
•精 养 ••I半nten精siv e养
•i•nS粗teemnsi养-ive
•Extensive
•放
养密 度
•天然 饵料
•Density •Natural
fish and larvae of aquatic invertebrates. The mortality of
these animals would be markedly increased in the absence of
such refuge, thus would further affect the biodiversity of the
东湖富营养化的成因分析和治理对策
•浮游藻类年平均总数不断增加
•50年代：27-949个/ml •60年代：156-4662个/ml •70年代：1000-35000个/ml
•（饶欽止、章宗涉，1980）
•The average annual total number of phytoplankton was steadily on the increase
way of transition from eutrophic to hyper-eutrophic (Cai,1993)
东湖富营养化的成因分析和治理对策
•氮的总输入量: •总负荷量: •磷的总输入量: •总负荷量:
536 t/a 19.22g/m2 87.8 t/a 3.15 g/m2
•输入-输出差: • •
•1950s: 27-949 ind/ml •1960s: 156-4662 ind/ml •1970s： 1000-35000 ind/ml
•（Jao and Zhang，1980）
东湖富营养化的成因分析和治理对策
•种类组成明显改变
•1956－1957: 甲藻 硅藻
•60年代：
蓝藻 绿藻
•微囊藻（Microcystis） •束丝藻（Aphanizomenon） •鱼腥藻（Anabaena）等
东湖富营养化的成因分 析和治理对策
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•东湖富营养化 •十分严重
•Serious eutrophication •in Lake Donghu
东湖富营养化的成因分析和治理对策
• 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
•（饶欽止、章宗涉，1980）
•Pronounced change occurred in the species
composition of phytoplankton
•1956-1957: Pyrrophyta Bacillariophyta
•1960s:
Cyanophyta Chlorophyta
2) The disappearance of aquatic macrophytes reduced the competition for
nutrients, causing the luxuriant proliferation of phytoplankton;
3) Dike construction within the lake diminished the exchange of water mass
lacking of macrophytes would deprive these eggs of such
substratum and depress the hatching rates substantially;
• 4）Macrophytes also serve as a sort of refuge for the fry of
• 2) Aquatic macrophytes compete for nutrients and light with phytoplankton
东湖富营养化的成因分析和治理对策
• 沉水植物的消失给水生态系统带来了一系列的影响
• 3）水草是好几种产粘性卵的鱼类、螺类以及水生
昆虫卵粒附着的基质，产出的鱼卵、虫卵、和螺的
1973－1985年:水柱日产量平均每年增长0.55•（4 戎g/克m文2﹒等天，1995 ）
•Primary productivity of phytoplankton increased
•rapidly 1963-1990: Average daily production at the layer of maximum
between Guozhenghu area and other lake areas with lower loading of N and
P.
4)
(Rong et al.,
1995)
•
东湖富营养化的成因分析和治理对策
• 3．鱼类“放养”与“精养”的区别
•The distinction between “fish-stocking” and “intense fish-farming” •
东湖富营养化的成因分析和治理对策
•草鱼（Ctenopharyngodon idellus）的 放养导致水生植物的消失
•Grass carp stocking resulted in the disappearance of macrophytes •
东湖富营养化的成因分析和治理对策
• 沉水植物的消失给水生态系统带来了一系列的影响 • 1）水生大型植物能起到净化水质的作用，它的消
O2/m2 per day.
•（Rong et al.，1995 ）
东湖富营养化的成因分析和治理对策
• 1）城市生活污水和工业废水大量排入，外 源污染加剧；
• 2）水草的消失减轻了对养料的竞争，促使 浮游藻类大量繁殖；
• 3）湖内人工堤的修筑，减少了郭郑湖区与 其他氮磷含量较低的湖区之间的水团交流