Fabio Aprile, Assad J. Darwich, Pedro A.S. Mera, Barbara A. Robertson, Bruce G. Marshall, & Gilmar W. Siqueira
The spatial-temporal variation of cyanobacteria was studied from 2002 to 2007 on the Madeira River, a river with muddy waters of Amazon origins in the Andes, whose main characteristics are the massive amount of material in suspension and relative wealth of nutrients and inorganic ions. The presence of cyanobacteria in Madeira River was not associated with high levels of pollution or organic contents. Unique species of white waters and typical species of clear waters were found. The genera Oscillatoria and Anabaena were predominant, with a significant concentration of species (46.8%), highest number of taxa (63%) and higher values of species richness (S) and diversity index (H0) on the headwaters during the high water levels. About 57% of the identified taxa were considered accidentals. The traditional communities consume water from the river without prior treatment, so it can not be ruled out intoxication by cyanotoxins.