Characterization of the physical and chemical parameters of Ubatuba Bay, Northern Coast of São Paulo State, Brazil

Abstract

The objective of the present study is to characterize the physical and chemical environmental parameters of Ubatuba Bay (SP), as a subsidy for studies of the composition and distribution of benthic crustaceans which live on the non-consolidated sublittoral bottom of this area. Depth, temperature, salinity, dissolved oxygen, organic content and granulometric composition of the sediments were measured monthly from September/95 to August/96 in eight subareas of the bay. The bay presents an average depth of 9.3 m and is characterized by the following annual mean values for the hydrologic factors: temperature 23.8 o C, salinity 33.2‰ and dissolved oxygen 5.11 mg/l. The annual mean for the organic matter content of the bay bottom sediments was 11.8% and most subareas presented a grain size composition dominated by pelitic sediments. These peculiar abiotic characteristics are very important for the reproduction and development principally of brachyuran and anomuran crabs, and shrimps which have a close relationship with those substrates.Key words: Crustacea, environmental factors, sediment, organic content, Ubatuba, Brazil. RESUMO Caracterização dos parâmetros físicos e químicos da Enseada de Ubatuba, litoral norte de São Paulo, BrasilO presente trabalho objetivou a caracterização de alguns parâmetros físicos e químicos da Enseada de Ubatuba (SP), como subsídio para estudos sobre composição e distribuição de invertebrados bentônicos associados ao substrato não-consolidado desta área, além de servir para comparações com cenários futuros da região. Foram estabelecidas oito subáreas para a amostragem dos parâmetros ambientais (profundidade, temperatura, salinidade e teor de oxigênio dissolvido na água, teor de matéria orgânica e granulometria do sedimento de fundo). Em todas a subáreas as coletas foram efetuadas mensalmente, durante três dias consecutivos, de setembro de 1995 a agosto de 1996. As amostras de água foram coletadas com uma Garrafa de Nansen e o sedimento de fundo com um pegador do tipo Van Veen (1/40 m 2 ). Os valores médios dos parâmetros encontrados na Enseada foram: profundidade (9,3 ± 3,66 m), temperatura (23,8 ± 0,62 o C), teor de oxigênio dissolvido (5,11 ± 0,29 mg/l), salinidade (33,2 ± 0,35‰) e teor de matéria orgânica (11,8 ± 5,35%). Quanto à granulometria, houve predomínio das areia fina e muito fina. Entre as subáreas, pode-se constatar diferenças significativas na profundidade, no teor de oxigênio dissolvido, no teor de matéria orgânica e na granulometria do sedimento. Os valores encontrados permite-nos caracterizá-la como uma enseada com um padrão semelhante às adjacentes, mas com parâmetros hidrológicos e sedimentológicos fortemente estabe-

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“…The bay shoreline has several sandy beaches interspersed by reef rocky shores. Streams and creeks drain into the bay giving to the water a mixopolihaline characteristic, low dynamism and a predominant fine and very sediment (Mantelatto, Fransozo, 1999).…”

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“…The samples were then re-weighed to calculate the organic-matter content. All these procedures followed those used by Mantelatto and Fransozo (1999b). Sediment grainsize composition was analyzed according to Bertini and Fransozo (2004).…”

Population biology of spine shrimp Exhippolysmata oplophoroides (Holthuis) (Caridea, Hippolytidae) in a subtropical region, São Paulo, Brazil

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“…Fresh water also enters from the Atlantic forest and the surrounding mangroves, reducing the salinity in the shallow water in the bay. MANTELATTO & FRANSOZO (1999) provided a detailed characterization of the physical and chemical parameters in Ubatuba Bay, during the same period as this study (Tabs I and II).…”