Epilithic diatoms as biological water quality indicators--A study in three geographically isolated hill streams in...

Epilithic diatoms from three geographically isolated hill streams of Central and Eastern India were studied and analysed to find their efficacy in determining difference in ecological conditions of aquatic systems. Three sampling sites (site-1, site-2 and site-3) shared commonness of being hill streams of forests with difference in source points. 34 diatom species were identified with species-richness of 17 at site 1, 10 at site 2 and 19 at site 3. Two sets of hypotheses-null (H01, H02 and H03) and alternative (HA1, HA2 and HA3) were framed. Null hypotheses were rejected in favour of alternative hypotheses. Diversity t-tests yielded significant 't' values: at (α < 0.0001 and < 0.002, implying differences within the sampling sites. Furthermore, Mann-Whitney, Kruskal-Wallis and Wilcoxon paired-sample tests were performed to test the alternative hypotheses, of which Kruskal-Wallis yielded significant difference between the sample medians with χ² = 5.457 at p = 0.03801, and Wilcoxon paired-sample test yielded significant differences between sampling site pairs at α(2) = 0.05 and 0.10. Thus significant differences could be established based only on diversity profile study of the epilithic diatoms.