Cyanobacteria in a subtropical reservoir of the province of Salta (Argentina).

Abstract

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, Planktolyngbia 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.