RESUMEN
The aim of the present research was to summarize the main reasons that explain the distribution of harmful blooms of cyanobacteria in Argentina. It is a large territory with climates ranging from humid tropical to cold temperate. We performed a meta-analysis of the published data and information in technical reports published from 1945 to 2015, and included additional data from personal non-published studies. A total of 122 water bodies affected by planktonic cyanobacterial blooms were recorded and geo-referenced. The analysis showed that blooms, defined as events exceeding 5000 cells/mL, occurred in different types of water bodies, including shallow lakes, rivers, streams, reservoirs, estuaries and storage facilities. Maximum bloom abundance and species and ecological strategies (dispersive, scum-forming, nitrogen fixer) responsible for each event were related to the geographic and climatologic characteristics and type and origin of water bodies. The Puna and the Andean Patagonia eco-regions were mostly free of blooms. The most impaired aquatic systems were shallow lakes and reservoirs (46.7 and 24.6%, respectively). Deep lakes had no reports of blooms and rivers were mainly affected at the regulated reaches, with intensities generally decreasing downstream the dams. Besides, 74.3% of the 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 the blooms. Microcystis aeruginosa, Dolichospermum spiroides, Dolichospermum circinale, Raphidiopsis mediterranea and Cylindrospermopsis raciborskii were frequently found participating in either mixed or single species blooms. The species distribution was associated with the eco-region and aquatic system typologies and affected by seasonality and climatological and geographic variables. The eco-strategies of cyanobacterial species showed stronger associations with the qualitative and quantitative indicators used in the meta-analysis, and appeared as useful tools for management measures.
Asunto(s)
Cianobacterias , Eutrofización , Argentina , Lagos , PlanctonRESUMEN
Cylindrospermopsis raciborskii (Woloszyn´ ska) Seenayya et Subba Raju 1972 es una especie capaz de generar diversas toxinas que impactan negativamente sobre la calidad del agua destinada al consumo humano así como a otros usos de la misma. Cepas del hemisferio norte producen la hepatotoxina cilindrospermopsina, mientras que las sudamericanas generan las toxinas neurotóxicas saxitoxinas. No se ha reportado hasta el momento la producción de microcistinas por parte de esta especie El objetivo del presente estudio fue analizar la presencia de microcistinas en el agua del Arroyo Yatay en Corrientes, Argentina, y de cilindrospermopsina, saxitoxinas y microcistinas en cepas de C. raciborskii aisladas del mismo, mediante el ensayo por Inmuno Absorción Ligado a Enzimas (ELISA). Los resultados dieron negativos para microcistinas en el agua cruda, así como de cilindrospermopsina y saxitoxinas en el cultivo algal. Sin embargo, en el agua del cultivo se detectaron concentraciones de 2,34-2,50 µg. L-1 de microcistina-LR, confirmándose posteriormente su presencia mediante su análisis por Cromatografía Líquida de Alta Resolución (HPLC). En estudios posteriores se deberán realizar análisis moleculares a los fines de establecer la caracterización genética de la cepa en estudio e investigar su relación filogenética con otras cepas provenientes de diversos ambientes a nivel mundial.
Cylindrospermopsis raciborskii (Woloszyn´ ska) Seenayya et SubbaRaju 1972 is a species capable of generating toxins that negatively impact on drinking water quality as well as other water uses. Northern strains can produce the hepatotoxin cylindrospermopsin, while southern strains can produce the neurotoxin saxitoxins. Microcystins production by this species has not been reported to date.The aim of this study was to analyze the presence of microcystins in raw water of Steam Yatay in Corrientes, Argentina, and cylindrospermopsin, saxitoxins and microcystins in strains of C. raciborskii isolated from that stream, by means of Enzyme-Linked Immuno Sorbent Assay (ELISA).Results were negative for microcystins in raw water, as well as for cylindrospermopsin and saxitoxins in algal culture. Microcystins were detected in algal culture by ELISA test, at concentrations of 2.34-2.50 µg. L-1 of microcystin-LR, and subsequent confirmation by means of High Performance Liquid Chromatography (HPLC). Molecular studies should be carried out in the future to establish the genetic characterization of the strain under study and investigate their phylogenetic relationship with other strains from diverse environments.