Origem e composição da matéria orgânica sedimentar na margem continental próximo a Cabo Frio (RJ), porção sul da Bacia de Campos, costa sudeste do Brasil

• Autor(a) principal: Oliveira, Dulce Raquel Pereira
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/13866
• topic: Organic matter; Lipids; Cabo Frio; Campos Basin; Matéria orgânica; Lipídios; Cabo Frio; Bacia de Campos; CNPQ::CIENCIAS EXATAS E DA TERRA::OCEANOGRAFIA

Lipid biomarkers [fatty acids (FA), sterols and alcohols] and total organic carbon (TOC) were analyzed in 48 superficial (0-2 cm) sediment samples collected in two periods (winter 2008/2009 and summer/2009) in two transects ranging from 25 m to 3000 m depths and that encompass the major region of occurrence of upwelling events in the southeastern Brazilian continental margin and where the river influence is probably minimal. The objectives were (i) to evaluate the sources, transport and major areas of organic matter (OM) accumulation in the continental margin and (ii) to identify the fraction of OM that is potentially available to secondary benthic producers. This study is part of a larger project entitled "Habitats Project - Campos Basin Environmental Heterogeneity by CENPES /PETROBRAS". As expected, lipids derived from primary (0.058 - 3.1 mg gTOC-1) and secondary (0.015 - 2.2 mg gTOC-1) producers made the major fraction of the sedimentary OM, whereas lipids from allochthonous sources (0.043 - 0.40 mg gTOC-1) and from bacteria (<0.01 - 0.43 mg gTOC-1) were of less importance. The accumulation patter of OM in the sediments is highly dependent of coupling of physical (hydrodynamics) and biological (response to upwelling) properties, and when compared to previous data on the same region have no seasonal trend. It was found that while some restricted areas in the shelf may be a sink of labile OM, the export of this material to the upper and middle slope (400 to 1000 m depths) is significant, which represents an important source of bioavailable OM to the deep-sea benthic community.