The climatic rhythm and blooms of cyanobacteria in a tropical reservoir in São Paulo, Brazil

Abstract

The present study sought to develop a methodology to analyse water quality based on the concepts and methods of climate and climatology. Accordingly, we attempted to relate hydro-and limnometeorological techniques and methodologies to a rhythmic analysis technique developed within the context of the Brazilian geographical climatology. Our goal was to assess and analyse cyanobacterial blooms, the main index of water quality for the reservoirs of the "Alto Tietê" Basin and, consequently, the Metropolitan Region of São Paulo, an area of high environmental complexity due to its high degree of development and high population density. The meteorological data used were collected by the Institute of Astronomy, Geophysics and Atmospheric Sciences at the University of São Paulo meteorological station, and the limnological data were collected through the Hydrological Monitoring System implemented by SABESP in the Billings and Guarapiranga Reservoirs and the laboratory of the same entity. The rhythmic and integrated analysis showed that the process of cyanobacterial blooms is dependent on a combination of meteorological factors as temperature and wind intensity that may disrupt the stability of the reservoir, providing the conditions necessary for the development of cyanobacteria during the stabilisation process. The pace of the Atlantic Polar Front Entrance during the winter in São Paulo is a limiting factor for the growth of cyanobacteria because of their high frequency, thus maintaining the balance of the reservoir throughout this period. The weather types those could cause a instability in the water column were: Cold Front entrance (66.67%), conflict between masses (22.22%) and the Tropical Instability Line (11.11%). The possibility for prevention and forecasting periods advise when these reservoirs should not be used, mainly with regard to recreational activities.Keywords: geographical climatology, rhythmic analysis, stratification, mixing, cyanobacteria. O ritmo climático e as florações de cianobactérias em um reservatório tropical em São Paulo, BrasilResumo O presente trabalho buscou desenvolver uma metodologia para análise da qualidade da água com base em conceitos e métodos do clima e da climatologia respectivamente. Dessa forma, buscou-se relacionar técnicas e metodologias hidrometeorológicas e limno-meteorológicas com a técnica de análise rítmica desenvolvida dentro da climatologia geográfica brasileira para avaliar e analisar as florações de cianobactérias, principal índice de qualidade de água encontrado nos reservatórios da Bacia do Alto Tietê e consequentemente da Região Metropolitana de São Paulo, área de alta complexidade ambiental devido ao seu alto grau de desenvolvimento e a sua alta densidade populacional. Os dados meteorológicos utilizados para o desenvolvimento do trabalho foram coletados a partir da estação meteorológica do Instituto de Astronomia, Geofísica e Ciências Atmosféricas da Universidade de São Paulo e os dados limnológicos foram coletados por meio do Sistema de Monitoramento Hidrol...

Performance Analysis of MODIS 500-m Spatial Resolution Products for Estimating Chlorophyll-a Concentrations in Oligo- to Meso-Trophic Waters Case Study: Itumbiara Reservoir, Brazil

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Effects of atmospheric cold fronts on stratification and water quality of a tropical reservoir: implications for aquaculture

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Variations of Rainfall Rhythm in Alto Pardo Watershed, Brazil: Analysis of Two Specific Years, a Wet and a Dry One, and Their Relation with the River Flow

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