Assessment of phytoplankton in the Escaba reservoir, Tucumán, Argentina, in order to characterize the water quality.

Abstract

The aim of this study was to analyze space-time variations of phytoplankton in the limnetic zone of the Escaba reservoir and the mouth of its tributary rivers, Chavarría, Las Moras, El Chorro and Singuil, and compare these with physicochemical variables in order to characterize the water quality between 2010 and 2012. One hundred and thirty-five taxa were determined: 77 Bacillariophyceae, 40 Chlorophyta, 12 Cyanophyta, 5 Euglenophyta and 1 Dinophyta. Algal density varied between 84 and 6,924 individuals/ml with Ceratium hirundinella as the dominant species, except for the spring of 2011. Chlorophyll-a varied seasonally and in space with values between 6 and 2,511 ?g/l, with higher numbers for the affluents. Elevated biomass values and the polysaprobic character of the waters defined a deficient or bad ecological status. The specific diversity oscillated between 0 and 2.76. The generalized linear model detected changes in the abundancy of C. hirundinella between the two seasons, the sites and months assayed, which were associated with differences in certain physicochemical variables (ammonium, DO and BOD5) A negative relationship was only observed between dinoflagellates and ammonium in November 2011. The present study has provided new information regarding the algal biodiversity of the Escaba dam and distribution of C. hirundinella in the Tucumán province.