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区域环境与生态

Effect of major ions on the communities of benthic diatoms in Karst rivers from the Zhujiang Watershed

摘要：为了建立喀斯特地区河流底栖硅藻对水环境变化的响应模型,定量研究了中国西南喀斯特地区黔桂珠江水系典型岩溶水体中的离子、电导率与底栖硅藻群落分布的关系.研究发现,电导率的范围为20～2070μS·cm^-1,并且Ca²⁺与(HCO₃^-+CO₃^2-)是岩溶水体的主要优势离子.对离子、电导率与硅藻群落结构进行主成分分析(PCA)、对应分析(CA)、加权平均分析(WA)和相关性分析,结果表明,水体离子(HCO₃^-+CO₃^2-、SO₄^2-、NO₃^-、Cl^-、Ca²⁺、Na⁺、Mg²⁺、K⁺)与电导率环境变量都能用于解释底栖硅藻的群落分布特征;而Ca²⁺、(HCO₃^-+CO₃^2-)和Na⁺浓度是影响物种组成的显著因素.通过研究确定了以上8种水体离子和电导率的相应指示种值(最适值Optima),以及这些离子环境下的硅藻分布特征.该结果为中国西南喀斯特地区硅藻种群生态学、个体生态学以及水质评价的研究提供了理论依据.

Abstract：In order to establish a water quality response model for the Karst region of China using benthic diatoms,the relationships between major ions,conductivity and the distribution of benthic diatom communities from the ZhuJiang Watershed within a Karst region of southwest China were quantitatively studied.The conductivity ranged from 20 μS·cm^-1 to 2070 μS·cm^-1,and Ca²⁺,(HCO₃^-+CO₃^2-) were the dominant ions in calcific water columns.Principal component analysis(PCA),correspondence analysis(CA),weighted averaging(WA) and correlation between ions,conductivity and communities of benthic diatoms showed that the content of major ions(HCO₃^-+CO₃^2-,SO₄^2-,NO₃^-,C1^-,Ca²⁺,Na⁺,Mg²⁺,K⁺) and conductivity together explained a statistically significant amount of the variation in the composition of the benthic diatom community.Ca²⁺,(HCO₃^-+CO₃^2-) and Na⁺ were the most significant factors affecting changes of diatom composition.The corresponding indicator values(optima) for conductivity,major ions and the distribution of diatom communities influenced by all eight ions were ascertained.These species optima could be applied in research on diatom ecology and autecology,and could be regarded as criteria for evaluating the water quality of the Karst region of Southwest China.

Key words：Karst QianGui Zhujiang watershed benthic diatoms major ions conductivity