A Functional Analysis of the Benthic Macrofauna of the São Sebastião Channel (Southeastern Brazil) |
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| Authors: | Emilia Arasaki Pablo Muniz & Ana Maria S Pires-Vanin |
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| Institution: | Escola Politécnica da Universidade de São Paulo, Laboratório de Hidráulica;Av. Prof. Lúcio Martins Rodrigues, 120. CEP 05508-900, São Paulo, Brazil.; Sección Oceanología, Departamento de Ecología, Facultad de Ciencias;Iguá4225, Montevideo, 11400, Uruguay.; Instituto Oceanográfico da Universidade de São Paulo, Caixa Postal 66149, CEP 05315-970, São Paulo, Brazil. |
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| Abstract: | Abstract. The major problem in coastal areas of developing countries is disturbance caused by anthropogenic influence. This disturbance can be quantified by analysing the distribution and composition of marine communities using uni- and multivariate techniques and the biotic index. A study of benthic macrofauna was carried out along the São Sebastião Channel, northern coast of São Paulo State, Brazil, in an area with a submarine outfall, a petroleum terminal and a commercial harbour. Sampling was undertaken seasonally, by means of a van Veen grab (0.1 m2) at 15 oceanographic stations, from November 1993 to August 1994. A total of 392 species were identified (129 Polychaeta, 127 Mollusca, 98 Crustacea, 28 Echinodermata and 10 other phyla). The sedimentary pattern recorded for the São Sebastião Channel is very heterogeneous, influenced mainly by strong wind-driven currents, and differs from nearby shelf areas. The study area could be divided into three regions based on sediment texture and fauna: one region dominated by medium and coarse sand with low values of organic carbon; a second area where pelitic fractions were dominant with high values of organic carbon and nitrogen; and a third region characterised by fine and very fine sand, presenting intermediate organic carbon values. No temporal significant variation in abundance and species composition was found, except in autumn. The use of the 'marine Biotic Coefficient' showed the same ecological trend as the faunal abundance and demonstrated that the central continental region of the channel is affected by human activities. |
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| Keywords: | Benthic macrofauna distribution patterns biotic index São Sebastião Channel Brazil |
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