Resumo

VELEZ-AZANERO, Armando; LOZANO, Sebastián  e  CACERES-TORRES, Keytel. Phytoplankton diversity as an indicator of water quality in the lower basin of the Lurín river, Lima, Perú. Ecol. apl. [online]. 2016, vol.15, n.2, pp.69-79. ISSN 1726-2216.  http://dx.doi.org/10.21704/rea.v15i2.745.

Six sampling points (P) were established from 5 to 31 meters above sea level in the lower basin of the Lurin River, in august 2008, to evaluate the physical and chemical characteristics of water, and to determine how water quality relates to diversity of microalgae and Cyanobacteria. Five species of Cyanobacteria were recorded and 89 species of microalgae from four divisions were encountered. Bacillariophyta was the most abundant division and accounted for 72% of all species. The genera Navicula, Fragilaria, Nitzschia and Synedra accounted for 31.2% of the total identified species. A total of 29 genera and 55 species were identified exclusively from one of the sampling points. A gradual decrease of the similarity from the two stations with higher altitude (39.3%) to the two lower stations (18.2%) was evident. The highest conductivity value was recorded at 31 meters above sea level (1820 μS.cm-¹) and the lowest at 5 meters above sea level (1390 μS.cm-¹). The lowest pH values were registered at higher elevations (6.2; 6.1), and the maximum value at 8 meters above sea level (8.2); this shows an inverse correlation between both variables. Temperature values ranged from 23°C to 16°C and it was directly related to altitude. Replacement levels, which increase with increasing spatial distance between sampling points, clearly showed the sensitivity of microalgae and Cyanobacteria to environmental changes. These changes are reflected in a high mineralization and low pH levels in the water, and are mainly due to natural and anthropogenic causes.

Palavras-chave : Abundance; Bacillariophyta; Cyanobacteria; Lurin river; microalgae; sensitivity; similarity.

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