2009 Volume 25 Pages 153-156
Three diatom indices, Diatom Assemblage Index to organic water pollution (DAIpo), the water quality evaluation of Japanese-type River (WQEJR), and the trophic diatom index (TDI), were calculated based on epipelic diatom assemblages to test their applicability. The dominant diatom taxon was Navicula gregaria at three out of the five sampling sites. At the other two sites, Nitzschia inconspicua and Nitzschia dissipata var. media were the dominant species, respectively. Based on epipelic diatoms, the three diatom indices showed almost the same correspondences to the water quality as those based on epilithic diatoms. Correlations between the indices and the water quality were, however, not as expected from the nature of the indices. For instance, higher values of TDI at sites with low phosphorus concentrations were associated with the dominance of N. gregaria, which usually indicates high phosphorus concentrations on stones.
