Environmental management and Ecology research


Biological monitoring is valuable method used in conservation studies to protect and preserve the biological integrity of natural ecosystem, which includes preventive measures. Bioindicators of pollutants are useful in predicting the level and degree of pollutants before the effects of the pollutants start.


The objective of this study is to investigate the diversity, genera composition, and seasonal variation of phytoplankton in relation to physicochemical variables.


Water samples have been ongoing collected every two months from 10 sampling sites on the Na Thap River, Songkhla province, Thailand, since June 2005. Five upstream sites are situated in the freshwater zone, with increasing salinity toward the river mouth. Analytical methods used are based on the standard method of the American Public Health Association, the American Water Works Association, and the Water Environment Federation (1998).

Multivariate analyses were used to investigate the relationships between phytoplankton density and physicochemical variables. Exploratory factor analysis with maximum likelihood estimation was used to identify underlying factors describing the correlations among the physicochemical variables. The appropriate number of factors was determined using a chi-squared test statistic. Multivariate multiple linear-regression analysis was then used to evaluate phytoplankton density in relation to the reduced set of physicochemical variables obtained from the factor analysis.


A research methodology is established to analyze the ecological data.


  • Methods proposed in our study can be applied to larger and wider areas.


1. Lueangthuwapranit C., Sampantarak U. and Wongsai S. 2011. Distribution and abundance of phytoplankton: influence of salinity and turbidity gradients in the Na Thap river, Songkhla province, Thailand. Journal of Coastal Research. 27(3), 585-594.
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