CONICET | Buscador de Institutos y Recursos Humanos

The aim of the present research was to summarize the main reasons that explain the distribution of harmfulblooms of cyanobacteria in Argentina. It is a large territory with climates ranging from humid tropical to coldtemperate. We performed a meta-analysis of the published data and information in technical reports publishedfrom 1945 to 2015, and included additional data from personal non-published studies. A total of 122 waterbodies affected by planktonic cyanobacterial blooms were recorded and geo-referenced. The analysis showedthat blooms, defined as events exceeding 5000 cells/mL, occurred in different types of water bodies, includingshallow lakes, rivers, streams, reservoirs, estuaries and storage facilities. Maximum bloom abundance andspecies and ecological strategies (dispersive, scum-forming, nitrogen fixer) responsible for each event were relatedto the geographic and climatologic characteristics and type and origin of water bodies. The Puna and theAndean Patagonia eco-regions were mostly free of blooms. The most impaired aquatic systems were shallowlakes and reservoirs (46.7 and 24.6%, respectively). Deep lakes had no reports of blooms and rivers were mainlyaffected at the regulated reaches, with intensities generally decreasing downstream the dams. Besides, 74.3% ofthe blooms reported in Argentina exceeded WHO Alert Level 2 for drinking and bathing waters (100,000 cells/mL). Thirty-nine species, identified by Komárek?s polyphasic approach to taxonomy, were responsible for theblooms. Microcystis aeruginosa, Dolichospermum spiroides, Dolichospermum circinale, Raphidiopsis mediterranea andCylindrospermopsis raciborskii were frequently found participating in either mixed or single species blooms. Thespecies distribution was associated with the eco-region and aquatic system typologies and affected by seasonalityand climatological and geographic variables. The eco-strategies of cyanobacterial species showed stronger associationswith the qualitative and quantitative indicators used in the meta-analysis, and appeared as useful toolsfor management measures.