Research Article
Fabio Aprile, Assad J. Darwich
Abstract
Floristic composition, abundance, richness and many other ecological patterns of phytoplankton and phytoperiphyton were studied in the Madeira River basin, between the Abunã River and Porto Velho City (Rondônia - Brazil), taking into account the hydrological period of the region. The results were correlated with abiotic factors, including the nutrients Na+ , K+ , Ca2+, Mg2+, N-NO3 - , P-PO4 3- and chlorophyll-a. 283 taxa on the Madeira River and 327 taxa in the tributaries were identified belonging to six divisions and nine taxonomic classes. It was observed a considerable complexity in floristic composition, with a greater contribution from the division Chlorophyta, especially during the high water periods, when there was greater species richness recorded. Ecological indexes and statistical analysis confirmed strong seasonal pattern and differentiation between the species present in the white and clear waters.