太湖贡湖湾滨岸带微生境特征与主要水质指标的关系分析

Analysis of relationship between Microhabitat Characteristics and Major Water Quality Indicators in Littoral Zone of Gonghu Bay,Tai Lake

2014年8月26日和2015年1月18日,测量了太湖贡湖湾北侧的退圩还湖生态修复区滨岸带不同微生境下水体的主要水质指标,并进行了比较。采用单因素方差分析法,分析不同微生境下水质指标的差异,结合冗余分析法,计算各微生境因子对水质指标变化的解释率。结果表明,8月26日各主要水质指标含量都高于1月18日,不同岸线段之间和不同水深采样点之间的水质指标的差异更大。1月18日凹形岸线段的总氮、总磷、铵态氮和硝态氮的含量相对较高,而化学需氧量在凸形和平直岸线段含量相对较高;8月26日化学需氧量在凹形岸线段含量较高,而总磷和铵态氮在凸形岸线段含量相对较高。冗余分析发现,在1月18日岸线形态是影响各采样点主要水质指标最重要的因子,在8月26日水深对水体水质指标有较大影响。总体上,不同岸线形态段下水质指标随着水深的增加,变化不同,各岸线类型采样点之间的差异也不相同,构建相对复杂的岸线形态有利于提高水体水质指标的差异,增加滨岸带生境的多样性。

The major water quality indicators were compared in different microhabitats in an ecological restoration area（embankment returning to lake） in the north of Gonghu Bay, Tai Lake. The concentrations of the major water quality indicators were measured. The differences between different microhabitats were tested by one-way Analysis of Variance and every microhabitat factor＇s explanatory power on water quality was calculated based on redundancy analysis. The results showed that the major water quality indicators on August 26,2014 were higher than those on Janurary 18, 2015 and the heterogeneities among different forms of shorelines and different water depths were more evident. The concentrations of total nitrogen, total phosphorus, ammonia nitrogen and nitrate nitrogen on Janurary 18, 2015 were relatively higher under the concave shoreline, and the concentration of chemical oxygen demand was comparatively higher under the convex and straight shorelines, while on August 26, 2014, the concentration of chemical oxygen demand was relatively higher under the concave shoreline, and the concentrations of total phosphorus and ammonia nitrogen were comparatively higher under the convex shoreline. Redundancy analysis results showed that shoreline morphology was the most significant microenvironmental factor that affected the main water quality indicators on Janurary 18, 2015;while on August 26, 2014, water depth was the most significant microenvironmental factor that affected the major water quality indicators. In general, the major water quality indicators changed differently among different shorelines along the water depth gradient, also the heterogeneities among different shorelines existed. On August 26, 2014, building relatively tortuous shorelines could increase the heterogeneity of water quality indicators, thereby enhance the diversity of littoral habitat.