The genus Gomphonema (Bacillariophyta) in the periphytic community of the Curuá-Una river and reservoir (Santarém, Pará, Brazil)

Abstract The Gomphonema genus is well represented in terms of richness and abundance in periphytic communities in freshwater environments. This study aimed to know the composition and richness of the Gomphonema genus attached to aquatic macrophytes in the littoral zone of the Curuá-Una river and reservoir. Samplings were performed in November/2011 (dry period) and July/2013 (rainy period). For the morphological and morphometric analysis of the diatoms the samples were oxidized and prepared in permanent slides. The material was studied under optical and scanning electron microscopy. As results we registered 13 specific and infraspecific Gomphonema taxa. The most representative in the two hydrological periods were: G. parvulum var. lagenula, G. pantropicum, and G. naviculoides, the first are widely cited in Brazilian flora, and the last considered first record to Brazil and Pará.