Contribution

First report of the cyanobacterium Aphanizomenon schindleri (Nostocales, Cyanophyceae) in River Uruguay, Argentina

Otaño, Silvia Haydeé

Abstract

Aphanizomenon schindleri, initially described from Canadian lakes, is here reported for the first time for Argentina. Water samples were collected from River Uruguay from January to April 2008. Anabaena spiroides was dominant from January to mid March, with a maximum of 87,700 cells mL-1 corresponding to 91 % of the phytoplankton biomass. Aphanizomenon schindleri was dominant from mid March to April, with a maximum of 447,600 cells mL-1 corresponding to 93 % of the phytoplankton biomass. Both A. spiroides and A. schindleri were present when the level of the river was extremely low, together with high temperatures. Other cyanobacteria observed were Microcystis aeruginosa, Cylindrospermopsis raciborskii, Aphanizomenon sp. and Anabaena sp. Toxin analysis from natural samples did not detect microcystins or saxitoxins. These blooms affected the drinking water supplies in the Provinces of Misiones and Corrientes.

Mots-clefs

aphanizomenon schindleriargentinacyanobacterium