Effects of algicide (Copper Sulfate) application on short-term fluctuations of phytoplankton in Lake Paranoá, Central Brazil

Abstract

Short-term fluctuations and structure of phytoplankton were examined for two months in the dry season (August-September/1997) in a eutrophic reservoir of central Brazil. Algicide treatment for the control of Microcystis aeruginosa bloom influenced the short-term variation pattern of the phytoplankton community. Algicide treatment was effective in controlling M. aeruginosa bloom, but it also influenced the Cylindrospermopsis raciborskii population. These species retained low densities, showing small colonies and trichomes, respectively. Drops in Cyanobacteria populations following algicide treatment were succeeded by progressive increase in Chlorophyta. The shifts in environmental conditions may have allowed the development of this group. In this study correspondence analysis of abundance data for phytoplankton assemblage in lake Paranoá revealed that available light, rather than chlorophyll-a, total suspended material, and water temperature, accounted for most of the short-term fluctuation in phytoplankton structure during algicide application. Canonical correspondance analysis (CCA) showed the primary importance of water transparency changes in abundance of taxa in the community. Algicide treatment for the control of nuisance blooms is discussed as a contribution to improved efficiency in reservoir management.Key words: Cyanobacteria, Chlorophyta, reservoir, Brazil. RESUMO Efeitos da aplicação de algicida (sulfato de cobre) sobre flutuações de curta duração do fitoplâncton no lago Paranoá, Brasil centralFlutuações de curta duração e a estrutura do fitoplâncton foram analisadas ao longo de dois meses na estação seca (agosto-setembro de 1997) em reservatório eutrófico do Brasil central. A aplicação de algicida para o controle de florescimentos de Microcystis aeruginosa exerceu influência sobre a variação temporal da comunidade fitoplanctônica, sendo efetiva também no controle do florescimento de M. aeruginosa e sobre a população de Cylindrospermopsis raciborskii. Ambas permaneceram em baixas densidades numéricas, com pequenas colônias e tricomas, respectivamente. Quedas bruscas de populações de Cyanobacteria após o tratamento de algicida foram seguidas por progressivo aumento de Chlorophyta. Mudanças de condições ambientais podem ter permitido o desenvolvimento deste último grupo. Análise de correspondência de dados de abundância do fitoplâncton no lago Paranoá revelou que a variável luz disponível se relacionou mais à flutuação de curta duração em estrutura do fitoplâncton do que a clorofila-a, o material suspenso total e a temperatura da água. A ACC constatou que as mudanças de transparência de água foram de primordial importância na abundância dos taxa fitoplanctônicos. O tratamento de algicida no controle de florescimentos algais é discutido aqui em relação ao gerenciamento eficiente de reservatórios.Palavras-chave: Cyanobacteria, Chlorophyta, reservatório, Brasil.

Ecological status assessment of tropical reservoirs through the assemblage index of phytoplankton functional groups

“…Thereby, mixing conditions and high light and nutrient availability were favorable to the development of species of this FG. Moreover, studies have recorded that the treatment with copper sulfate can lead to the growth of Chlorophyceae populations after the decreasing in cyanobacteria populations (Padovesi-Fonseca and Philomeno 2004;Rouco et al 2014).…”

Limnological evaluation of water in the Rio Grande and Taquacetuba branches of the Billings Complex (São Paulo, Brazil) and management implications (doi:10.4136/ambi-agua.153)

“…More recently in the Paiva Castro Reservoir, located in the metropolitan region of São Paulo city, near the municipality of Mairiporã, applications occur mainly in summer. There are also regular applications of copper sulfate for phytoplankton control in Lake Paranoá (Distrito Federal, Brazil) (Padovesi-Fonseca and Philomeno, 2004) and Jundiai Reservoir (São Paulo) (Table 4). Table 4.…”

Impact of copper sulfate application at an urban Brazilian reservoir: A geostatistical and ecotoxicological approach

“…Despite the ecotoxicological and human health implications of copper sulfate, it offers an easy and relatively inexpensive technique for water body management, producing a rapid environmental response (Padovesi-Fonseca and Philomeno, 2004;Kansole and Lin, 2017). Nevertheless, the use of copper sulfate is not the only option for water quality management (Beaulieu et al, 2005;Huh and Ahn, 2017).…”