Artigos Científicos - FAOCE/IG

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2803

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Acesso aberto (Open Access)
Composição e variabilidade espaço-temporal da meiofauna de uma praia arenosa na região amazônica (Ajuruteua, Pará)
(2009-06) GOMES, Tatianne Pereira; ROSA FILHO, José Souto
The present study investigates the spatio-temporal changes in the meiofauna community along the intertidal zone of Ajuruteua Beach, State of Pará, Brazil. Samples were collected during spring tides at different levels of the beach face every two months from April 2003 to February 2004. The material was sampled using a cylindrical corer (3.14 cm2) and fixed with 5% saline formalin. In the laboratory, samples were sieved through a 0.063 mm mesh screen and the retained organisms were identified at higher taxonomic levels, counted and preserved in ethanol 70%. Meiofauna was composed of eight groups: Turbellaria, Nematoda, Tardigrada, Polychaeta, Oligochaeta, Acari, Copepoda and nauplius (Copepoda). Nematoda was the dominant group, representing 74% of total organisms, followed by Copepoda (19%). A clear faunal zonation was observed on three lines parallel to the shoreline, which showed significant differences in abundance, richness and density of the main taxonomic groups. The mean density was lowest in April and highest in December. The highest densities and richness were recorded in the mid intertidal zone, while the lowest values were recorded in the upper and lower intertidal zones. Meiofauna community was most rich and abundant during the dry months, although differences were not significant between climatic periods. The main factors
Acesso aberto (Open Access)
Dinâmica sazonal de nutrientes em estuário amazônico
(2015-04) MONTEIRO, Sury de Moura; EL-ROBRINI, Maâmar; ALVES, Igor Charles Castor
This paper shows the nutrients distribution in the Paracauari estuary over a Amazon hydrological cycle (2008), and at the end of the period of La Niña (April 2008). This estuary is influenced by the humid tropical climate and meso-tidal (3 to 4 m), semi-diurnal. Sampling was conducted at 10 stations in three distinct seasons: rainy (march), intermediate (june) and less rainy season (september). Were measured in situ physical and chemical parameters using a multiparameter probe; analyzed the dissolved nutrients (nitrate, nitrite, ammonia- -N, phosphate and silicate) by spectrophotometry and particulate matter suspension, gravimetrically. We observed large seasonal variations in the concentrations of the studied parameters. The water temperature (average of 28.58 °C) is quite homogeneous, typical of tropical waters. The pH ranged acid (5.80) to alkaline (7.86) and salinity between 0.06 to 7.56, with both maximum values at the mouth because of the greater marine influence. The waters are poorly oxygenated during the rainy season (2.35 mg.L-1) and at the very least rainy (6.55 mg.L-1). The concentrations of the suspended particulate matter and nutrients reached a maximum during the rainy season due to the natural inflow from adjacent areas. In this estuary, the nutrients are mainly controlled by the river discharge, rainfall, wind and tide and exceptionally by la Niña.
Acesso aberto (Open Access)
Foraminifera, thecamoebians and palynomorphs as hydrodynamic indicators in Araguari Estuary, Amazonian Coast, Amapá State - Brazil
(2010-12) LAUT, Lazaro Luiz Mattos; FERREIRA, Daniele Esteves da Silva; SANTOS, Valdenira Ferreira dos; FIGUEIREDO JÚNIOR, Alberto Garcia de; CARVALHO, Marcelo de Araújo; MACHADO, Odete Fátima
The Araguari estuarine dynamics is singular among traditional models of estuaries under tidal regime due to influence of macrotidal and tidal bore. In order to establish estuarine zones in Araguari according foraminifera, thecamoebians, paliynomorphs and physical-chemistry parameters, sixteen sample stations were established along the estuary. Turbidity and temperature were the environmental parameters which allowed determination of the estuarine gradient. Eighteen species of foraminifera, ten of thecamoebians and fourteen of particulate organic matter types were identified. Cluster analysis in R-mode showed three microorganism assemblages and four palynomorph ones. The CCA analyze shows turbidity and total organic matter with the most influence over foraminiferal and thecamoebians distribution at Araguari. Clustering analysis in Q-mode using all data formed four groups suggesting three estuarine zones in Araguari: Zone I composed of thecamoebian species and continental palynomorphs; Zone II - composed by mangrove foraminifera, thecamoebians and all palynomorph assemblages; and Zone III - composed by mangrove and estuarine foraminifera and all palynomorph assemblages.
Acesso aberto (Open Access)
Ictiofauna do estuário de São Caetano de Odivelas e Vigia (Pará, Estuário Amazônico)
(2011-06) BARROS, Daniela de França; TORRES, Marcelo Ferreira; FRÉDOU, Flávia Lucena
Fish diversity in the Amazon Basin is recognized as one of the highest in the world. However, information on the estuarine ichthyofauna of the region is still fragmented and based on localized inventories. This study reports on an inventory carried out in the estuaries of São Caetano de Odivelas and Vigia, State of Pará, a poorly known area within the Amazon Estuary. Two research cruises of four days long each were undertaken in 2003, one in June (austral winter) and other in December (summer), with use of gill nets, traps, cast net and hook-and-line. It was collected 1,689 individuals, including 58 species from 23 families, all of them previously recorded in the Amazon Estuary. Perciformes, Siluriformes and Clupeiformes were the most diverse taxa, comprising 73.8% of the species. From the 58 recorded species, 24% are pelagic, 50% are demersal and the remaining have pelagic-demersal habits. Coastal-marine species predominated in the region.

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