62 resultados para benthic ecology

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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The main aim of the present study was to evaluate and compare temporal responses of the benthos in 2 continental shelf areas (Cabo Frio and Ubatuba) off the SE Brazilian coast. In Cabo Frio (23 degrees S, 42 degrees W), the western boundary coastal upwelling of the South Atlantic Central Water (SACW) enhances primary productivity, potentially increasing food supply to the benthic communities via sinking of particulate organic carbon (POC). In contrast, POC fluxes in Ubatuba (23 degrees S, 45 degrees W) are expected to be comparatively lower because SACW remains subsurface. We analyzed the temporal and spatial input of phytodetritus (concentration of chlorophyll a in sediments) and the benthic microbial biomass (estimated by ATP-based carbon content in sediments). Median surface chlorophyll concentration was computed for all daily available SeaWiFS images (from 2001 and 2002) to follow chlorophyll a inputs. All parameters used to investigate benthic responses in the study areas showed consistently higher values in Cabo Frio than in Ubatuba. The results showed that benthic response to upwelling may last months, fueling the microbial communities in the Cabo Frio region.

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The goal of this work was to examine the occurrence of brachyurans in soft bottom sublittoral habitats and their association with some environmental factors. The relative abundance of crabs in two depth strata (from 4.5 to 9 m and from 9 to 18 m) was quantified. Crabs were collected with an otter-trawl with 3.7 m of mouth opening and 12-mm mesh in the cod end. Monthly sampling, consisted of a single trawl in each stratum during a 1-yr period, were carried out. Fifteen brachyuran and six anomuran species were found, including Callinectes ornatus Ordway, 1863; Callinectes danae Smith, 1869; Hepatus pudibundus (Herbst, 1785); Libinia spinosa H. Milne-Edwards, 1834; Persephona punctata (Linnaeus, 1758), and P. mediterranea (Herbst, 1794), which were the most abundant and frequent in the area. The most abundant swimming crabs in both strata were C. ornatus and C, dan(re. Size differences in C. ornatus were observed between strata, suggesting a spatial separation of juveniles and adult crabs.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A case of envenomation caused by the Nemalecium lighti is described. The hydrozoan species lives in many kinds of substrates, being quite common in tropical shallow water. The patient, a marine biologist, had contact with the animal in two different opportunities while snorkeling. Both contacts produced erythematous and highly pruriginous papules in exposed areas of the body. The signs and symptoms persisted for a week and healed without sequellae. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The aim of the present study was to examine the benthic fauna in a marginal pond lateral to the Paranapanema River and to identify the main controlling factors of its distribution. Considering the small size of the lacustrine ecosystem, we expected that seasonal variations of the benthic community attributes are more important than spatial variations; Methods: Two samplings, one in March and another in August, were carried out at nine sites in the pond. Sediment samples were obtained through a Van Veen grab for invertebrate sorting, granulometric analysis, and for quantification of organic matter in sediment. Other abiotic factors were measured, such as water transparency, dissolved oxygen, pH, electric conductivity, temperature, and depth of sediment sampling sites. Regarding the comparative analysis at spatial scale, no significant variations in density of the benthic invertebrate community were found. Results: In relation to the studied abiotic factors, only depth presented significant differences among sampling sites; All the measured environmental parameters presented significant differences among sampling months, except depth and the physical and chemical characteristics of the sediment. The abundance of Chaoboridae and Chironomidae was the unique attribute with a significant difference in comparing the two months. A higher abundance of taxa occurred in August, especially for Oligochaeta, Nematoda, Chaoboridae, and Chironomidae; Conclusions: Because of the low structural complexity of the studied pond, we concluded that the changes in benthic macroinvertebrate community attributes were mainly due to seasonal effects.