A taxonomic study is presented of the predominant periphytic diatoms from three streams, Nazaré, Guaiapó and Remo, influenced by different anthropogenic actions. Samples were taken bimonthly in three sites of the stream watercourse, headwater, middle and mouth, from July 2007 to August 2008. Twenty six predominant species was recorded, from a total of 151 identified diatoms in the analyzed samples. Seven species were abundant or dominant in the three studied streams: Eolimna minima (Grunow) Lange-Bertalot (dominant in Remo stream), Gomphonema lagenula Kützing (dominant in Guaiapó stream), Gomphonema pumilum (Grunow) Reichardt & Lange-Bertalot and Nupela praecipua (Reichardt) Reichardt (both dominant in Nazaré stream), Geissleria aikenensis (Patrick) Torgan & Oliveira, Nitzschia palea (Kützing) Smith and Sellaphora seminulum (Grunow) Mann (abundant in three streams). Two species were abundant exclusively in Nazaré urban stream, 13 in Remo rural streams and six in Guaiapó stream that is influenced by both environments.
algae; lotic ecosystem; river basin; taxonomy
