2009年与2014年太子河流域附石藻群落结构变化及其与水环境的关系

为了解近年来太子河流域附石藻群落结构和水环境状况的变化趋势及二者的响应关系，于2009年和2014年对太子河全流域的附石藻群落和水环境因子进行调查分析，并探究了基于附石藻群落保护的主要水环境因子浓度限值.结果表明:①与2009年相比，2014年太子河流域的附石藻密度、物种丰富度、群落多样性均显著升高（P < 0.05）；群落组成中对不良环境干扰呈负响应的藻属相对多度普遍升高，对不良环境干扰呈正响应的藻属相对多度普遍降低.②与2009年相比，2014年水环境因子中ρ（TDS）（TDS为总溶解性固体）、ρ（SS）、ρ（TN）、和ρ（NO₃--N）显著降低（P < 0.05），ρ（DO）显著升高（P < 0.05）.典范对应分析（canonical correspondence analysis，CCA）显示，2009年ρ（TN）和ρ（NH₄+-N）是影响太子河流域附石藻群落的重要水环境因子；2014年ρ（TN）、ρ（NH₄+-N）和ρ（TDS）对附石藻群落结构有重要影响.③经局部加权回归散点修匀法（locally weighted scatterplot smoothing，LOWESS）和独立样本t检验得出，当ρ（TDS）、ρ（TN）和ρ（NH₄+-N）分别为185.00、1.00和0.22 mg/L时，其与P-IBI构成的拟合曲线存在拐点，且拐点两侧的P-IBI差异性显著（P < 0.05）.研究显示，2009—2014年太子河流域的附石藻群落和水环境状况整体有所改善，合理控制ρ（TN）、ρ（NH₄+-N）和ρ（TDS）对该流域的附石藻群落保护有重要意义. 

Variation of Periphyton Community Structure in 2009, 2014 and Their Relationship with Environmental Factors in Taizi River Basin

As one of the most important tributary in Liaohe River Basin, Taizi River Basin is a region of industrial and agricultural production base and energy base. Under the extensive economic development mode, Taizi River encounters serious water pollution and deteriorative aquatic ecosystem problem. To ensure ecosystem health and human sustainable development, the National Water Pollution Control and Management Technology Major Project has been implemented in Taizi River Basin since 2009. Periphyton, which usually grows on stone surface, is sensitive to a wide range of environmental variables, because its community structure could response quickly to physical, chemical and biological variations in the environment. To access the aquatic ecological condition of Taizi River Basin in recent years, the periphyton communities and aquatic environment factors at 44 sampling sites in 2009 and 2014 were investigated and analyzed, and the concentration limits of primary water environmental factors were also explored for the periphyton community protection. The results were as followed:(1) Compared with those in 2009, the integrity of periphyton community was improved, especially periphyton density, species richness and community diversity were significantly increased (P<0.05) in 2014. Otherwise, there was a general increase in the relative abundances of the periphyton species with negative response to the adverse environmental disturbance in 2014, and the relative abundances of the periphyton species with positive response to the adverse environmental disturbance were generally decreased in community composition. (2) Compared with 2009, TDS, SS, TN and NO₃^--N concentrations were significantly improved (P<0.05), and the concentration of DO was significantly decreased (P<0.05) in 2014. By Canonical Correspondence Analysis, the total nitrogen and ammonia nitrogen were the primary environmental factors affecting periphyton assemblage structure in 2009, whereas the total dissolved suspended solids, TN and NH₄⁺-N were the dominant factors (P<0.01) in 2014. (3) The results of LOWESS and independent sample t test indicated that P-IBI scores significantly changed when TDS concentration > 185.00 mg/L, TN concentration > 1.00 mg/L and NH₄⁺-N concentration > 0.22 mg/L. Concentration therefore, this study can provide data support for the aquatic ecological protection in Taizi River Basin and theoretical basis for water environment management in China.