Review of toxic species of Cyanobacteria in Brazil
Sant'Anna, Célia L. Azevedo; Teresade P. Werner, Vera R.; Dogo, Camila R.; Rios, Fernanda R. de Carvalho
In spite of the great environmental and sanitary importance of cyanobacteria, their biodiversity is little known in South America, including Brazil. Thus, based on literature data and studied material, a review of and discussion about toxic cyanobacteria and their occurrence in Brazil were carried out. In relation to literature data, only information confirmed by specific methods for cyanotoxin analysis was considered. The Brazilian toxic cyanobacteria are represented by 32 species: 12 Chroococcales, 10 Oscillatoriales and 10 Nostocales. The tropical region of Brazil presents a smaller biodiversity of toxic cyanobacteria (14 species) than do the subtropical parts of the country (27 species). Microcystis (7 species) and Anabaena (6 species) are the genera with the highest number of toxic species. Microcystis aeruginosa and Cylindrospermopsis raciborskii are the most widespread toxic cyanobacteria in Brazil, occurring in different parts of tropical and subtropical regions. To date, the Brazilian species Radiocystis fernandoi has been registered forming toxic blooms only in tropical areas of Brazil. In relation to toxic species of Oscillatoriales, except Planktothrix agardhii, all of them present toxic occurrences restricted to the subtropical region of Brazil. The small size of the filaments of the majority of planktic Oscillatoriales and the fact that they normally do not form blooms seem to account for the little knowledge of this group in Brazil.