Aplicação de índices de qualidade da Diretiva Quadro da Água (DQA), para o fitoplâncton, em reservatórios do estado de São Paulo, Brasil
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Data
2019-11-27
Autores
Rodrigues, Eduardo Henrique Costa
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Universidade Estadual Paulista (Unesp)
Resumo
A eutrofização representa um dos principais impactos ambientais observados nos ecossistemas aquáticos. Tal impacto, entre outras consequências, promove o comprometimento da qualidade da água em muitos ambientes, incluindo reservatórios, que apresentam grande importância devido aos seus múltiplos usos. O objetivo principal deste trabalho é determinar o status ecológico de reservatórios do estado de São Paulo, através de Indicadores de Qualidade da Água superficial da Diretiva Quadro da Água (DQA), tendo o fitoplâncton como elemento da qualidade ecológica nesse processo. Amostras integradas da coluna d’água (toda zona fótica) dos reservatórios Igaratá, Atibainha, Paiva Castro, Itupararanga, Rio Grande, Broa, Barra Bonita, Guarapiranga e Salto Grande foram tomadas nas zonas lóticas, central e barragem. Análises relacionadas a estrutura do fitoplâncton e a organização das espécies descritoras organizadas em grupos funcionais foram realizadas. Um capitulo foi reservado para o estudo do Ceratium furcoides nestes ambientes. Os reservatórios aqui estudados, estão situados em diferentes bacias hidrográficas e fazem parte de diferentes sistemas produtores que abastecem o Estado de São Paulo. A amostragem ocorreu durante a estiagem em 2015. Em campo foram determinados a profundidade, a temperatura, oxigênio dissolvido (OD), condutividade elétrica (EC) e pH da água; em laboratório foram determinados a clorofila-a, os sólidos suspensos (SS) e os nutrientes, nitrito (N-NO2-), nitrato (NO3--), amônio (NH4+), nitrogênio total (NT), ortofosfato (P-orto) e fosforo total (TP), além do estado trófico (IET). As análises quali-quantitativas do fitoplâncton foram realizadas em microscópio binocular invertido, foram determinadas a densidade, diversidade, equitabilidade e dominância do fitoplâncton. A ordenação dos dados ocorreu através da analise de componentes principais (PCA) e análise de correspondecia canônica (CCA). Duas metodologias foram utilizadas no processo de determinação do potencial ecológico dos reservatórios, a primeira baseada na diversidade das espécies e a segunda na biomassa, utilizando os índices Eveness E2 e Q-Index respectivamente. As características limnológicas observadas entre os reservatórios são similares a ambientes tipicamente degradados ou em processo de degradação. Os reservatórios mais eutrofizados registraram maiores valores para a concentração de nutrientes e pigmentos. As cianobactérias foram dominantes nos ambientes eutróficos, associadas a baixa diversidade e elevada dominância. Os GF’s LO, LM e H1 foram os maiores contribuintes para a biomassa do fitoplâncton nos pontos amostrais onde ocorreram. A ordenação dos pontos amostrais, realizada pela PCA, evidenciou um gradiente trófico, partindo de um ambiente oligo-mesotrófico a super-hipereutrófico seguindo a ordem. Grande parte dos reservatórios apresentou problemas com a eutrofização e com a bioinvasão de Ceratium furcoides. A aplicação dos índices Eveness E2 e Q-Index mostrou resultados coerentes ao serem utilizados em ambientes tropicais. O Eveness E2 Index respondeu bem ao restante dos reservatórios e serve como medida complementar ao biomonitoramento dos reservatórios, não deixando de se investigar outros componentes. A avaliação da qualidade das massas d’água dos reservatórios através do Q-Index apresentou um bom desempenho ao ser utilizada em ambientes tropicais com diferentes graus de trofia, entretanto foi afetado significativamente por medidas de manejo aplicadas nestes ambientes.
Eutrophication represents one of the main environmental impacts observed in aquatic ecosystems. Such impact, among other consequences, promotes compromised water quality in many environments, including reservoirs, which are of great importance due to their multiple uses. The main objective of this work is to determine the ecological status of reservoirs in the state of São Paulo, through the Surface Water Quality Indicators of the Water Framework Directive (WFD), having phytoplankton as an element of ecological quality in this process. Integrated samples from the water column (all photic zone) of the Igaratá, Atibainha, Paiva Castro, Itupararanga, Rio Grande, Broa, Barra Bonita, Guarapiranga and Salto Grande reservoirs were taken in the lotic, central and dam zones. Analyzes related to phytoplankton structure and the organization of descriptor species organized into functional groups were performed. A chapter has been reserved for the study of Ceratium furcoides in these environments. The reservoirs studied here are located in different watersheds and are part of different producing systems that supply the state of São Paulo. Sampling occurred during the drought in 2015. In the field, depth, temperature, dissolved oxygen (OD), electrical conductivity (EC) and water pH were determined; Chlorophyll-a, suspended solids (SS) and nutrients, nitrite (N-NO2-), nitrate (NO3--), ammonium (NH4 +), total nitrogen (NT), orthophosphate (P-ortho) and total phosphorus (TP) were determined in the laboratory in addition to the trophic state (TSI). Qualitative and quantitative analyzes of phytoplankton were performed under inverted binocular microscope, and the phytoplankton density, diversity, equitability and dominance were determined. Data ordering occurred through principal component analysis (PCA) and canonical correspondence analysis (CCA). Two methodologies were used in the process of determining the ecological potential of reservoirs, the first based on species diversity and the second on biomass, using the Eveness E2 and Q-Index índices respectively. The limnological characteristics observed between the reservoirs are similar to typically degraded or degrading environments. The most eutrophic reservoirs recorded higher values for the concentration of nutrients and pigments. Cyanobacteria were dominant in eutrophic environments, associated with low diversity and high dominance. GF's LO, LM and H1 were the major contributors to phytoplankton biomass at the sampling points where they occurred. The ordering of the sampling points, performed by the PCA, showed a trophic gradient, starting from an oligo-mesotrophic to super hypereutrophic environment following the order. Most reservoirs had problems with eutrophication and Ceratium furcoides bioinvasion. The application of the Eveness E2 and Q-Index índices showed consistent results when used in tropical environments. The Eveness E2 Index responded well to the rest of the reservoirs and serves as a complementary measure to reservoir biomonitoring, while investigating other components. The quality assessment of reservoir water masses by Q-Index performed well when used in tropical environments with different degrees of trophy, however it was significantly affected by management measures applied in these environments.
Eutrophication represents one of the main environmental impacts observed in aquatic ecosystems. Such impact, among other consequences, promotes compromised water quality in many environments, including reservoirs, which are of great importance due to their multiple uses. The main objective of this work is to determine the ecological status of reservoirs in the state of São Paulo, through the Surface Water Quality Indicators of the Water Framework Directive (WFD), having phytoplankton as an element of ecological quality in this process. Integrated samples from the water column (all photic zone) of the Igaratá, Atibainha, Paiva Castro, Itupararanga, Rio Grande, Broa, Barra Bonita, Guarapiranga and Salto Grande reservoirs were taken in the lotic, central and dam zones. Analyzes related to phytoplankton structure and the organization of descriptor species organized into functional groups were performed. A chapter has been reserved for the study of Ceratium furcoides in these environments. The reservoirs studied here are located in different watersheds and are part of different producing systems that supply the state of São Paulo. Sampling occurred during the drought in 2015. In the field, depth, temperature, dissolved oxygen (OD), electrical conductivity (EC) and water pH were determined; Chlorophyll-a, suspended solids (SS) and nutrients, nitrite (N-NO2-), nitrate (NO3--), ammonium (NH4 +), total nitrogen (NT), orthophosphate (P-ortho) and total phosphorus (TP) were determined in the laboratory in addition to the trophic state (TSI). Qualitative and quantitative analyzes of phytoplankton were performed under inverted binocular microscope, and the phytoplankton density, diversity, equitability and dominance were determined. Data ordering occurred through principal component analysis (PCA) and canonical correspondence analysis (CCA). Two methodologies were used in the process of determining the ecological potential of reservoirs, the first based on species diversity and the second on biomass, using the Eveness E2 and Q-Index índices respectively. The limnological characteristics observed between the reservoirs are similar to typically degraded or degrading environments. The most eutrophic reservoirs recorded higher values for the concentration of nutrients and pigments. Cyanobacteria were dominant in eutrophic environments, associated with low diversity and high dominance. GF's LO, LM and H1 were the major contributors to phytoplankton biomass at the sampling points where they occurred. The ordering of the sampling points, performed by the PCA, showed a trophic gradient, starting from an oligo-mesotrophic to super hypereutrophic environment following the order. Most reservoirs had problems with eutrophication and Ceratium furcoides bioinvasion. The application of the Eveness E2 and Q-Index índices showed consistent results when used in tropical environments. The Eveness E2 Index responded well to the rest of the reservoirs and serves as a complementary measure to reservoir biomonitoring, while investigating other components. The quality assessment of reservoir water masses by Q-Index performed well when used in tropical environments with different degrees of trophy, however it was significantly affected by management measures applied in these environments.
Descrição
Palavras-chave
Diretiva Quadro da Água, Fitoplâncton, Eutrofização, Avaliação ecológica