Planktonic cyanobacteria from urban lakes in Manaus (Amazonas - Brazil)

Abstract

The aim of this research was to study the diversity of planktonic cyanobacteria in three urban lakes in Manaus, in the state of Amazon, by analyzing samples collected monthly with a plankton net from October 2009 to September 2010 (except March 2010). Twelve species were identified and classified. Anathece cf. minutissima, Aphanocapsa annulata, Ap. stagnalis, Coelomoron microcystoides and Pseudanabaena mucicola were recorded for the first time in the Brazilian Amazon region. Potentially toxic cyanobacteria blooms occurred in all three lakes, especially in Ceasa and Japiim, where Microcystis aeruginosa and Planktothrix agardhii, respectively, were the predominant species in all analyzed samples. Descriptions and illustrations of the identified species are presented as well as comments. In addition, environmental variables were presented (electrical conductivity, pH and water temperature). The waters of the studied environments ranged from slightly acid to alkaline and temperature varied from 23.2 to 30.5 °C.