论文部分内容阅读
The relations between lake surface sediment diatoms and water environmental variables were revealed effectively by use of a new multivariate canonical correspondence analysis (CCA) based on 45 lakes in the Tibetan Plateau. Water depth, conductivity, Cl~(-), Mg~(2+), K~(+) and pH, identified from 12 contemporary water environmental variables, can significantly and independently explain the diatom distributions (p<0.05). The first two axes (λ1=0.34, λ2=0.27) capture 16.1% of the variance in the species data, and account for 57.4% of the variance in diatom-environment relationship. The deletion of redundant environmental variables and unusual samples do not influence the explanation to diatom data. The final CCA result indicates that the water depth and the salinity are the two important environmental gradients and influence the diatom distribution in the plateau lakes. The water depth correlates with axis 1, while conductivity, Cl~(-), Mg~(2+) and K~(+), indicating the direction of salinity changes, corr
The relations between lake surface sediment diatoms and water environmental variables were clearly (by using a new multivariate canonical correspondence analysis (CCA) based on 45 lakes in the Tibetan Plateau. Water depth, conductivity, Cl ~ (-), Mg ~ +), K ~ (+) and pH, identified from 12 contemporary water environmental variables, can significantly and initially explain the diatom distributions (p <0.05). The first two axes (λ1 = 0.34, λ2 = 0.27) capture 16.1% of the variance in the species data, and account for 57.4% of the variance in diatom-environment relationship. The deletion of redundant environmental variables and unusual samples do not influence the explanation to diatom data. The final CCA result indicates that the water depth and the salinity are the two important environmental gradients and influence the diatom distribution in the plateau lakes. The water depth correlates with axis 1, while conductivity, Cl ~ (-), Mg ~ (2+) and K ~ (+), indicating the direction of sal inity changes, corr