Bivariate and multiple regression analyses were done to determine what variables correlated with the BDM metric. Bivariate regression between (BDM) metric scores and log conductivity was significant (R2= .47, p = .0001). Bivariate regression between GLEI metric scores and TP was significant (R2= .40, p< .0001). Bivariate regession betwee BDM scores and NO2 was significant (R2= .24, p< .0001).
Multiple regression between BDM metric scores and the variables was performed with Type I ANOVA used to remove variables from the full transformed variable data set with the smallest ssq. The best multiple regression model relating water chemistry to BDM scores included in order of importance, log conductivity, log TP, and log NO2 (Radj2= .64, p< .0001).
What this means: The BDM metric scores which are a measure of health of the diatom periphyton assemblages are significantly related to the anthropogenic impacts that shape these assemblages. The analysis was done to explore the relationship between the BDM metric scores and the pollutants affecting the diatoms.
