Influence of Metals on the Cyanobacterial Community in a Water Supply System in a Tropical Region.

This work aimed to study the influence of metals on the temporal dynamics of cyanobacteria community in Carpina Dam (7° 53' 22'' S and 35° 20' 34'' W). Samples were collected from Raw Water Pumping Station at the Water Treatment Station Feira Nova in the city of Feira Nova (Pernambuco, Brazil), from January 2011 to December 2013. The concentration of metals in water (aluminum, antimony, barium, lead, copper, chromium, cadmium, iron, manganese) was determined by atomic absorption spectroscopy in the laboratory. For the identification and counting of cyanobacteria, an inverted optical microscope and Sedgewick-Rafter counting chambers were used. Principal Component Analysis (PCA) was used for recognition of cluster patterns between the studied points. There were variations in abiotic and biotic components in the different years of study. The metals iron, aluminum, barium and manganese had the greatest influence on the temporal dynamics of cyanobacteria in the reservoir.

Seasonal changes of water quality in a tropical shallow and eutrophic reservoir in the metropolitan region of Recife (Pernambuco-Brazil).

This study investigated the water quality in an urban eutrophic reservoir in Northeastern Brazil, considering the influence of seasonality. Monthly, samples were collected in the sub-surface reservoir. The following abiotic variables were analyzed: temperature, pH, dissolved oxygen, apparent color, turbidity, conductivity, fluoride, total nitrogen, chlorides, total dissolved solids, total hardness, iron, copper, manganese, aluminum, chlorophyll-a and phaeophytin. Total and thermotolerant coliforms were analyzed according to APHA (2012). Cyanobacteria density was quantified through its biomass. The data were analyzed using one- way ANOVA and Pearson correlation test. Higher values mean phytoplankton biomass (26.3mm3.L-1) occurred in the dry season, especially Planktothrix agardhii and Geiterinema amphibium, which occurred in 100% of samples. High trophic state index was detected throughout the year. Seasonality exerted some influence on both biotic and abiotc variables, leading to changes in water quality of the reservoir.