太湖梅梁湾水源地通过生态修复净化水质的试验

Experiment on water purification by ecological measures in water sources of Meiliangwan of Taihu Basin

通过在太湖实施的试验研究,发现富营养化水体营养盐浓度的增加会导致附着在水生植物上的附着生物增加,对水生植物(主要是沉水植物)的光合作用造成胁迫,从而说明草型湖泊生态系统的恢复,首先必须降低营养盐浓度,因此,通过恢复水生植物来净化水质是不现实的。与营养盐浓度相比,风浪、光照、鱼的牧食等都不是根本的影响因素。根据调查,示范区夏季盛行偏南风,吹程长,风浪较大,导致沉积物悬浮,影响水环境质量,而蓝藻水华易于在此堆积,这些都是影响该水域水质的主要因素。为此,在生态净化方面,以恢复漂浮植物和浮叶植物为主来净化水质,在工程净化措施方面,提出了消浪和控藻等工程措施,以及布设人工介质(渔网)富集附着生物来净化水质等措施。经过3年的实施,示范区的水质改善已经取得初步成效。

After experiment was made in the Taihu Basin, it is found that the increase of concentration ol nutnent salt in eutrophic water bodies results in increasing attaching organism on aquatic flora, and threatens the photosynthesis of aquatic flora, particularly submerged plant. It shows that reduction of concentration of nutrient salt is essential for the recovery of ecosystem of grass-type lakes, and it is unrealistic of applying recovery of aquatic flora for purification of water quality. Comparing to nutrient salt, wave, sunlight and fish eating are not key influence factors. According to investigation, by south wind is popular in summer in the pilot areas, it causes suspension of deposits due to long-distance blowing and big waves, so water quality is affected. The accumulation of blue algae phycophytes becomes the main reason of poor water quality in the area. Therefore, in the respect of ecological purification, it is suggested to recover floating vegetation and suspended plankton; in the respect of engineering purification measures, it is suggested to adopt wave-breaking and algae control, laying artificial medium （fishnet） absorb attaching organism for water purification. After three years＂ experiment, water quality in the pilot areas already makes oreliminarilv imorovement.