Diatom community structure along physicochemical gradients in upland river segments of Tamiraparani river system, South India

This study examines the diversity and distributional patterns of benthic diatom assemblages in the upland streams of Tamiraparani River system, southern part of Western Ghats of Peninsular India. A total of 168 benthic diatoms representing 16 orders, 32 families, and 47 genera were enumerated. Structuring of diatom community was dependent on the environmental conditions of the respective habitats. Canonical correspondence analysis described both physical habitat quality and water parameter gradient and factors that correlated significantly were substrate type, water temperature, dissolved oxygen and nitrate content. Gomphonema gandhii, Cocconeis placentula and Navicula cuspidate were strongly associated with sites with embedded substrates and clear water. Diatoms could be effective in assessing physical habitat alterations in streams.