Caracterização da comunidade de microcrustáceos e avaliação de potenciais predadores vertebrados e invertebrados em dois reservatórios na região noroeste do Estado de São Paulo
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Data
2011-02-28
Autores
Câmara, Carolina Figueira [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os microcrustáceos que ocorrem no zooplâncton são representados pelos cladóceros e copépodos e estão distribuídos nas zonas litorânea e pelágica dos ambientes aquáticos. O objetivo geral do presente trabalho foi caracterizar a comunidade de microcrustáceos das regiões litorânea e pelágica de dois reservatórios do noroeste do Estado de São Paulo, bem como relacionar os dados bióticos com os dados abióticos e avaliar os potenciais predadores invertebrados e vertebrados de Cladocera e Copepoda. Foram realizadas quatro amostragens no ano de 2009, incluindo as zonas pelágica e litorânea. A amostragem foi realizada com uma bomba de sucção, sendo a água filtrada em rede de plâncton com malha de 45 μm. Foram avaliados alguns parâmetros físicos e químicos da água, bem como clorofila a, material em suspensão e nutrientes totais. As larvas de Chaoboridae e os peixes foram coletados na estação seca de 2009 e chuvosa de 2010. Os reservatórios apresentaram características típicas de ambientes rasos, com pouca diferenciação entre as zonas litorânea e pelágica. O índice de estado trófico foi maior no período chuvoso indicando o processo de eutrofização ao qual estes reservatórios estão sujeitos. A presença de algumas espécies consideradas bioindicadoras do estado eutrófico também foi registrada nos reservatórios. Riqueza e diversidade de microcrustáceos foram estatisticamente maiores na zona litorânea do que na zona pelágica. A maior parte dos táxons registrados pertence ao grupo dos Cladocera (72,5%), enquanto que o número de espécies de Copepoda foi menor. Algumas espécies, principalmente de Cladocera, tiveram ocorrência exclusiva na zona litorânea. Cladocera também foi o grupo mais abundante nessa zona, enquanto Copepoda predominou na pelágica. A produção de ovos das principais espécies de Copepoda foi elevada na maior parte dos meses de estudo...
The zooplanktonic cladocerans and copepods occur in coastal and pelagic zones of aquatic environments. The main goal of this work were to: characterize the microcrustacean community in pelagic and littoral regions of two reservoirs in the northwestern state of São Paulo, find relations between the community and the biotic and abiotic data, and evaluate the potential invertebrates and vertebrates predators of Cladocera and Copepoda. Four samples were taken in 2009, including pelagic and coastal areas. Sampling was performed with a bilge pump and filtered through a plankton 45 μm mesh net. We evaluated some physical and chemical parameters of water and chlorophyll a, suspended matter and total nutrients. Chaoboridae (Diptera) larvae and fish were collected in dry season of 2009 and rainy season of 2010. Reservoirs are shallow and present similar littoral and pelagic zones. The trophic state index was higher in the rainy season indicating the eutrophication process by which these reservoirs are subject. The presence of some species considered bioindicators of the eutrophic state was also recorded. Richness and diversity of microcrustaceans were significantly higher in the coastal zone than in the pelagic one. Most taxa belong to Cladocera (72.5%), and some of these species occur exclusively in the coastal zone. Copepoda predominated on abundance in the pelagic and Cladocera in the coastal zone. Egg production of the main species of copepods was high and the picks usually coincided with higher densities of females. The size of microcrustaceans was different between pelagic and coastal areas and between dry and rainy seasons. Planktonic microcrustaceans were consumed mainly by III and IV instars of Chaoborus sp. larvae. Thirteen species of fish were recorded in the reservoirs. Astyanax fasciatus and young of Oreochromis niloticus were the mainly species that consumed zooplankton... (Complete abstract click electronic access below)
The zooplanktonic cladocerans and copepods occur in coastal and pelagic zones of aquatic environments. The main goal of this work were to: characterize the microcrustacean community in pelagic and littoral regions of two reservoirs in the northwestern state of São Paulo, find relations between the community and the biotic and abiotic data, and evaluate the potential invertebrates and vertebrates predators of Cladocera and Copepoda. Four samples were taken in 2009, including pelagic and coastal areas. Sampling was performed with a bilge pump and filtered through a plankton 45 μm mesh net. We evaluated some physical and chemical parameters of water and chlorophyll a, suspended matter and total nutrients. Chaoboridae (Diptera) larvae and fish were collected in dry season of 2009 and rainy season of 2010. Reservoirs are shallow and present similar littoral and pelagic zones. The trophic state index was higher in the rainy season indicating the eutrophication process by which these reservoirs are subject. The presence of some species considered bioindicators of the eutrophic state was also recorded. Richness and diversity of microcrustaceans were significantly higher in the coastal zone than in the pelagic one. Most taxa belong to Cladocera (72.5%), and some of these species occur exclusively in the coastal zone. Copepoda predominated on abundance in the pelagic and Cladocera in the coastal zone. Egg production of the main species of copepods was high and the picks usually coincided with higher densities of females. The size of microcrustaceans was different between pelagic and coastal areas and between dry and rainy seasons. Planktonic microcrustaceans were consumed mainly by III and IV instars of Chaoborus sp. larvae. Thirteen species of fish were recorded in the reservoirs. Astyanax fasciatus and young of Oreochromis niloticus were the mainly species that consumed zooplankton... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Microcrustaceans, Ecologia aquatica, Limnologia, Ecologia dos reservatorios - São Paulo (Estado), Microcrustáceos - Caracterização
Como citar
CÂMARA, Carolina Figueira. Caracterização da comunidade de microcrustáceos e avaliação de potenciais predadores vertebrados e invertebrados em dois reservatórios na região noroeste do Estado de São Paulo. 2011. 140 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2011.