太湖东部湖湾大型水生植物分布对水质的影响

调查了太湖东部湖湾(贡湖湾、光福湾、渔洋湾)秋季沉水与浮叶植物的种类组成、覆盖度及水体理化性质,分析了大型水生植物的生长与分布对湖水总氮、总磷、透明度与叶绿素(Chl-a)等水质因子的影响.结果表明,太湖东部不同湖湾大型水生植物的分布状况具有明显差异,其分布频度在4.8%~95.2%,并以马来眼子菜分布频度最高.大型水生植物的生长对水体营养盐含量、理化因子等具有较为明显的影响,水生植物生长区湖水不同形态营养盐含量均低于无水生植物生长区,其总氮与总磷平均含量分别低约39%与51%.此外,蓝藻水华首先会在有水生植物生长的区域堆积,且沉水植物生长优势区蓝藻水华堆积程度要高于浮叶植物生长优势区,表现为该区域Chl-a平均浓度最高,达11.15mg/L,而浮叶植物区Chl-a平均浓度为9.98μg/L,无水生植物区的水华堆积程度最低,其Chl-a平均浓度为7.19mg/L.因此,针对不同水生植物生长区,其水体富营养化治理策略亦不同.

Influence of macrophytes on water quality in the eastern bays of Lake Taihu,China

Effects of macrophyte growth and water quality distribution factors such as total nitrogen (TN), total phosphorus (TP), transparency and chlorophyll a were studied in an investigation on specie compositions, coverage of macrophyte and physicochemical properties of water body in eastern bays of Lake Taihu (Gonghu Bay, Guangfu Bay and Yuang Bay). The results showed that Potamogeton wrightii Morong was the most popular specie amony three bays. The coverage of macropyhte was spatially different among survey sites, with the coverage ranged from 4.8% to 95.2%. Nutrients in the macrophyte-coverage area were significantly lower than those in the non-macrophyte area with a decrease of TN and TP concentration of 39% and 51%, However, being locates at the border of Microcystis bloom region, the macrophytes also easy to catch the floating bloom, in which the submerged macrophytes showed higher ability to catch the bloom than floating macrophytes did. Therefore, different aquatic vegetation zones of Lake Taihu need the corresponding strategies to restore water quality.