WATER QUALITY STUDY AND ITS LINK TO THE ASSEMBLAGES OF MICROPHYTOPLANKTON AND BENTHIC MACROINVERTEBRATES OF THE LAGOON IN UNZUÉ PARK (GUALEGUAYCHÚ, ENTRE RÍOS)

Diamela Gianello; Elizabeth Ávila-Hernández; Eduardo Chaves; Irene Aguer y Melina Celeste Crettaz-Minaglia.

Abstract

Urban lagoons are important environments for cities due to the multiple functions they carry out. However, they often bear the impact of diverse activities. The city of Gualeguaychu (Entre Ríos, Argentina) counts on a small, not very deep urban lake located in a recreational area. In the period 2015-2017, 14 samplings were carried out to determine the physico-chemical and bacteriological variables through functional groups. A water quality index was applied (ISQA) and a biotic integrity index (IBI). The study area presented homogeneity with respect to the studied variables. High concentrations of phosphorous and organic matter with ISQA values reflected low water quality during the entire study period. For its part, the microphytoplankton assemblages were associated with shallow areas in murky waters with organic contamination. The macroinvertebrate assemblages presented low richness and an absence of waste disposal units as well as low IBI reflection perturbations for urbanisation. The lagoon suffered from serious organic contamination with severe effects of the zone’s heavy urbanisation generating the loss of eco-systemic functions.