Cianobacterial bloom and animal mass mortality in a reservoir from Central Argentina.

MANCINI, MIGUEL; RODRIGUEZ, CLAUDIA; BAGNIS, GUILLERMO; LIENDO, ALEJANDRA; PROSPERI, CARLOS; BONANSEA, MATIAS; GALIZIATUNDISI, JOSE

BRAZILIAN JOURNAL OF BIOLOGY

INT INST ECOLOGY

Lugar: SAO CARLOS, SP; Año: 2010 vol. 70 p. 841 - 845

1519-6984

Piedras Moras dam (34°10?19??S, 64°16?18??W; 832 ha), integrates a series of lakes belonging to Rio Tercero basin (Córdoba, Argentina). During March 2009 an algal bloom occurred, coinciding with several animal species mortality, mainly wild birds. The goal of this work was to establish the trophic status of the dam in relation with that mortality. Variables were evaluated in situ (temperature and water transparency) and samples were taken in order to identify algal species, Chl-a concentration (spectrophotometry) and toxins ?total microcystines- (inmuno-enzymatic assay, ELISA). Histopathology studies were made on Fulica sp. A strong heterogenity in water transparency was observed, and ?patches? of Potamogeton berteroanus distributed all along the dam, with Secchi minimal and medium values of 0.15 and 0.94 m. Chl-a concentration oscillated from 35,7 to 320,9 mg/m3 . Predominant phytoplankton species were Anabaena spiroides and Microcystis aeruginosa (Cyanophyceae). Water temperature was 27,8ºC (±0,88). Maximal value of total microcystine concentration was 0,23 ug/L. Chl-a concentration at the moment when mass mortality occurred (2022 mg/m3) and the histopathology observations strongly suggest that the animals decease was due to cianotoxins.