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Brazilian Journal of Biology
On-line version ISSN 1519-6984
OLIVEIRA, M. A.; TORGAN, L. C.; LOBO, E. A. and SCHARZBOLD, A.. Association of periphytic diatom species of artificial substrate in lotic environments in the Arroio Sampaio Basin, RS, Brazil: relationships with abiotic variables. Braz. J. Biol. [online]. 2001, vol.61, n.4, pp. 523-540. ISSN 1519-6984. http://dx.doi.org/10.1590/S1519-69842001000400002.
Associations of diatom species were identified, in the Arroio Sampaio Basin, Rio Grande do Sul, Brazil, based on monthly samplings over a year along Arroio Sampaio and its main tributaries, using polyamide thread as an artificial substrate. The species groupings showed four different environments: medium-lower course of Arroio Sampaio; and lower course of Arroio Teresinha; upper course of Arroio Sampaio; and lower course of Arroio Duvidosa. Among the physical and chemical variables measured, water pollution, particularly organic contamination and eutrophication, measured from BOD5 and total phosphate concentration, respectively, appeared to be one of the most important environmental factors determining the composition and structure of species associations in the area studied.
Keywords : periphytic diatoms; species association; lotic system.