Cianobacterias en un embalse subtropical de la provincia de Salta (Argentina)

Abstract

El embalse Limón se ha convertido en la principal fuente de agua potable para el 80% de lapoblación del norte de la provincia de Salta (22° 05?47,90??S-63° 44? 19,48?? W). Al presente, no existeinformación sistematizada de las algas del fitoplancton presentes en esta presa. Se analizaron 19muestras del período 2013-2015 en ambas fases del ciclo hidrológico, según técnicas estandarizadas,con el objeto de evaluar la representatividad de cianobacterias potencialmente tóxicas en Limón y suimportancia relativa en el fitoplancton. Existió un predominio de cianobacterias, con un incrementointeranual significativo, siendo éstas más abundantes en los estiajes, con un promedio de 110.160células en 2015, con predominio de Cylindrospermopsis raciborskii y Raphidiopsis mediterranea (75.027y 170.000 células/ml). Entre las especies con potencial toxicogénico se destacaron por sus densidadesAnabaenopsis elenkinii, Aphanizomenon gracile, Aphanocapsa annulata, Coelomoron tropicale,Chroococcus dispersus, C. raciborskii, Microcysis flos-aquae, Planktolyngbya limnetica, Pseudanabaenalimnetica, R. mediterranea y R. curvata. La representatividad del grupo dentro del fitoplancton fuesuperior al 70 %. Se concluye que el cuerpo de agua es un ambiente de riesgo y debe ser monitoreadopermanentemente para su empleo para agua de consumo humano.

Cyanobacteria in a subtropical reservoir of the province of Salta (Argentina). The Limón reservoir has become the main source of drinking water for 80% of the population of the north of the province of Salta (22° 05' 47.90'' S - 63° 44' 19.48'' W). At present, there is no systematized information on phytoplankton algae present in this dam. We analyzed 19 samples from the period 2013-2015, in both phases of the hydrological cycle, according to standardized techniques, in order to evaluate the representativeness of potentially toxic Cyanobacteria in Limón and their relative importance in phytoplankton. There was a predominance of Cyanobacteria, with a significant interannual increase, these being more abundant during dry season, with an average of 110,160 cells/ml in 2015, with a predominance of Cylindrospermopsis raciborskii and Raphidiopsis mediterranea (75,027 and 170,000 cells/ml repectively). Among the species with toxic potential, Anabaenopsis elenkinii, Aphanizomenon gracile, Aphanocapsa annulata, Coelomoron tropicale, Chroococcus dispersus, C. raciborskii, Microcysis flos-aquae, Planktolyngbya limnetica, Pseudanabaena limnetica,R. mediterranea and R. curvata were notable for their densities. The representativeness of this group within the phytoplankton was greater than 70%. It is concluded that the body of water is an environment of risk and must be monitored permanently for its use for water for human consumption.