Efeito da sazonalidade na diversidade fitoplanctônica do corpo Central 1 da Represa BIllings, São Paulo, Brasil
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Data
2019-12-02
Autores
Matarazzo, Matheus Peres [UNIFESP]
Orientadores
Nordi, Cristina Souza Freire [UNIFESP]
Tipo
Trabalho de conclusão de curso de graduação
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Resumo
A versatilidade da água e a influência que ela exerce sobre outros compostos, fazem dela uma das substâncias mais importantes para sobrevivência de todos os organismos, incluindo-se os seres humanos. Existe uma tendência da população a se aglomerar nas proximidades dos corpos hídricos, pois esses acabavam lhes proporcionando benefícios. A implantação de reservatórios fez se necessário para suprir as exigências da população em crescimento. Esse crescimento vem aumentando o impacto ambiental nas áreas de mananciais e a poluição dos corpos hídricos, prejudicando severamente a qualidade da água dos reservatórios de abastecimento. Neste contexto inclui-se a Represa Billings, o maior reservatório de água da Região Metropolitana de São Paulo e talvez o mais ameaçado pela poluição e eutrofização. Portanto o estudo da comunidade fitoplanctônica constitui-se uma importante ferramenta para o monitoramento dos impactos ambientais em decorrência do processo de eutrofização. São os principais produtores primários dos ecossistemas aquáticos e extremamente sensíveis as variações mínimas nas condições físicas, químicas e biológicas que interferem na dinâmica das espécies da comunidade fitoplanctônica. Por esse motivo resolvi determinar a diversidade da comunidade fitoplanctônica do Corpo Central I da Represa Billings utilizando métodos quantitativos e qualitativos e levando em conta a diversidade de espécies que a compõem. Com base na composição dos táxons podemos verificar, através de ferramentas estatísticas, se a comunidade fitoplanctônica sofre com a influência sazonal (períodos chuvoso e de estiagem) a qual o reservatório está submetido. Para essa pesquisa, foram escolhidos quatro pontos no Corpo Central I da Represa Billings levando-se em conta a heterogeneidade ambiental de cada um. Foram realizadas quatro coletas: duas no período de estiagem e duas no chuvoso, com o objetivo de verificar a dinâmica sazonal da comunidade fitoplanctônica. Os valores de densidade fitoplanctônica (ind/mL) determinados foram posteriormente convertidos em biovolume (mm³/L). Foi quantificada a diversidade α, através do Índice de Shannon-Wiener, a riqueza de espécies e a frequência de ocorrência dos táxons durante os períodos de coleta. Uma Análise de Componentes Principais (PCA) foi realizada no conjunto de dados com o intuito de verificar se existe uma influência sazonal agindo sobre a diversidade das espécies do fitoplâncton. Os resultados sobre diversidade e riqueza não evidenciaram grande variação sazonal no número de espécies durante os dois períodos estudados. Em relação à frequência de ocorrência nota-se que a maior representatividade se deve as espécies da divisão Cyanobacteria. Os resultados da PCA, no entanto, mostraram uma influencia sazonal atuando sobre a distribuição das divisões/classes do fitoplâncton durante os dois períodos (estiagem e chuvoso). Foi possível constatar que a sazonalidade tem efeito sobre a abundância dos grupos nos dois diferentes períodos analisados. Esse fato foi evidenciado pela predominância da divisão Cyanobacteria na estiagem junto com a queda das microalgas, enquanto no período chuvoso a tendência é aumentar a biomassa das microalgas. Esse efeito está interligado ao regime pluviométrico e seus efeitos indiretos sobre a represa, a predominância desse grupo evidencia o processo crescente de eutrofização do reservatório.
Water's versatility and its influence on other compounds make it one of the most important substances for the survival of all organisms, including humans. There is a tendency of the population to congregate near the water bodies, as these eventually provide them with benefits. The establishment of reservoirs was necessary to meet the demands of the growing population. This growth has been increasing the environmental impact on the watershed areas and the pollution of the water bodies, severely impairing the water quality of the supply reservoirs. This includes the Billings Dam, the largest water reservoir in the São Paulo Metropolitan Region and perhaps the most threatened by pollution and eutrophication. Therefore, the study of the phytoplankton community is an important tool for monitoring the environmental impacts due to the eutrophication process. They are the main primary producers of aquatic ecosystems and extremely sensitive to the minimal variations in physical, chemical and biological conditions that interfere with the dynamics of the phytoplankton community species. For this reason I decided to determine the diversity of the phytoplankton community of the Billings Dam Central Corps I using quantitative and qualitative methods and taking into account the diversity of species that comprise it. Based on the composition of the taxa we can verify, through statistical tools, if the phytoplankton community suffers from the seasonal influence (rainy and dry periods) to which the reservoir is subjected. For this research, four points were chosen in the Billings Dam Central Corps I, taking into account the environmental heterogeneity of each one. Four collections were carried out: two in the dry season and two in the rainy season, in order to verify the seasonal dynamics of the phytoplankton community. The phytoplankton density values (ind / mL) determined were later converted to biovolume (mm³ / L). The diversity α was quantified through the Shannon-Wiener Index, the species richness and the frequency of occurrence of taxa during the collection periods. A Principal Component Analysis (PCA) was performed on the dataset to verify whether there is seasonal influence acting on phytoplankton species diversity. The results on diversity and richness did not show great seasonal variation in the number of species during the two studied periods. Regarding the frequency of occurrence it is noted that the greater representativeness is due to the species of the Cyanobacteria division. The PCA results, however, showed seasonal influence acting on the distribution of phytoplankton divisions / classes during both periods (drought and rainy season). Seasonality has an effect on the abundance of the groups in the two different periods analyzed. This fact was evidenced by the predominance of the Cyanobacteria division in drought along with the microalgae fall, while in the rainy season the tendency is to increase the microalgae biomass. This effect is linked to the rainfall regime and its indirect effects on the dam, the predominance of this group highlights the growing process of eutrophication of the reservoir
Water's versatility and its influence on other compounds make it one of the most important substances for the survival of all organisms, including humans. There is a tendency of the population to congregate near the water bodies, as these eventually provide them with benefits. The establishment of reservoirs was necessary to meet the demands of the growing population. This growth has been increasing the environmental impact on the watershed areas and the pollution of the water bodies, severely impairing the water quality of the supply reservoirs. This includes the Billings Dam, the largest water reservoir in the São Paulo Metropolitan Region and perhaps the most threatened by pollution and eutrophication. Therefore, the study of the phytoplankton community is an important tool for monitoring the environmental impacts due to the eutrophication process. They are the main primary producers of aquatic ecosystems and extremely sensitive to the minimal variations in physical, chemical and biological conditions that interfere with the dynamics of the phytoplankton community species. For this reason I decided to determine the diversity of the phytoplankton community of the Billings Dam Central Corps I using quantitative and qualitative methods and taking into account the diversity of species that comprise it. Based on the composition of the taxa we can verify, through statistical tools, if the phytoplankton community suffers from the seasonal influence (rainy and dry periods) to which the reservoir is subjected. For this research, four points were chosen in the Billings Dam Central Corps I, taking into account the environmental heterogeneity of each one. Four collections were carried out: two in the dry season and two in the rainy season, in order to verify the seasonal dynamics of the phytoplankton community. The phytoplankton density values (ind / mL) determined were later converted to biovolume (mm³ / L). The diversity α was quantified through the Shannon-Wiener Index, the species richness and the frequency of occurrence of taxa during the collection periods. A Principal Component Analysis (PCA) was performed on the dataset to verify whether there is seasonal influence acting on phytoplankton species diversity. The results on diversity and richness did not show great seasonal variation in the number of species during the two studied periods. Regarding the frequency of occurrence it is noted that the greater representativeness is due to the species of the Cyanobacteria division. The PCA results, however, showed seasonal influence acting on the distribution of phytoplankton divisions / classes during both periods (drought and rainy season). Seasonality has an effect on the abundance of the groups in the two different periods analyzed. This fact was evidenced by the predominance of the Cyanobacteria division in drought along with the microalgae fall, while in the rainy season the tendency is to increase the microalgae biomass. This effect is linked to the rainfall regime and its indirect effects on the dam, the predominance of this group highlights the growing process of eutrophication of the reservoir