Abundance and composition of Rotifera in an abandoned meander lake (Lago Amapá) in Rio Branco, Acre, Brazil

A comunidade de rotíferos do Lago Amapá (meandro abandonado da planície de inundação do Rio Acre) foi investigada sazonalmente. As amostragens foram realizadas semanalmente em três estações de coletas, em dois períodos: estação seca entre 08/V/1997 e 31/X/1997 e estação chuvosa, entre 02/I/1998 e 24/II/1998. A densidade e composição de rotíferos (48 táxons de rotíferos) foram determinadas. A diversidade e abundância foram caracterizadas por serem maiores, respectivamente, nas águas altas e águas baixas. Anova e teste F foram usados, visando observar diferenças sazonais nas variáveis ambientais e rotíferos. Transparência e pH foram estatisticamente altamente significativos (p < 0,01). As análises de correlações de Pearson revelaram que a condutividade elétrica foi negativamente correlacionada com a densidade de rotíferos (r = -0,8824; p < 0,05), na fase de águas baixas, bem como, profundidade, na fase de águas altas (r = -0,7513; p < 0,05). Mudanças sazonais, causadas pelas flutuações do nível da água, e baixa diversificação dos nichos influenciaram a composição e abundância do grupo estudado.

The U-isotopes modeling in aquifers from Pocos de Caldas plateau, Brazil

U-modeled groundwater residence times were estimated by changes in U-234/U-238 activity ratio (AR) and U content of groundwaters from Pocos de Caldas city situated at the Pocos de Caldas alkaline massif, Brazil. The estimated ages are more realistic than others generated by the use of hydraulic conductivity data and available information about the weathering rate of rocks in the plateau. The U-234/U-238 AR and reciprocal of the dissolved U-content data also defined a ternary plot that allowed the calculation of the relative volume of three source waters for the mixed water. Such U-isotopes modeling for mixing calculations indicated that the dominant phase (68%) in the mixture is thermal.

A method for evaluating Ra-228 in environmental matrices and its use at Pocos de Caldas plateau, Brazil

This work describes a methodology developed for performing the extraction, detection and quantification of Ra-228 in waters, suspended solids and sediments. The technique proved to be useful for analyzing samples from the hydrological environment of Morro do Ferro, Pocos de Caldas plateau, Brazil. The 228Ra activity in underground waters of 5 boreholes drilled in the area varied from 0.02 up to 14.5 Bq/l, whereas for the surficial waters the variation was from 0.04 to 0.51 Bq/l; for the suspended solids, the values ranged from 1.5 up to 419 Bq/g, whereas it was possible to find a value of 2.04 Bq/g for the sediments. These results show the applicability of the method for characterizing different matrices of environmental interest. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Influence of water level variation on biomass and chemical composition of the aquatic macrophyte Eichhornia azurea (Kunth) in an oxbow lake of the Rio Mogi-Guacu (São Paulo, Brazil)

The influence of water level variation (flood pulse) on the biomass and chemical composition of the aquatic macrophyte Eichhornia azurea, was investigated in a tropical oxbow lake of the Rio Mogi-Guacu, State of São Paulo, Brazil. The flood pulse causes an increase in total nitrogen content from 0.67 to 1.35 mg/L and total phosphorus content from 10.5 to 101.0 mu g/L of the water. This fertilization, associated with other factors, determines a typical seasonal variation in the biomass and chemical composition of the macrophyte.

Denudation history of the Bocaina Plateau, Serra do Mar, southeastern Brazil: Relationships to Gondwana breakup and passive margin development

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

Feeding patterns in a fish community of Baia da Onça, a floodplain lake of the Aquidauana River, Pantanal, Brazil

The stomach contents of 24 species of fish and unidentified species from four genera in a floodplain lake of the Pantanal were studied. Fish were collected during the dry season when the lake was isolated from the main river. A community food ingestion index (feeding index weighted by consumer biomass, FIWCB, where 0 < FIWCB < 1) was calculated to quantify feeding patterns. Detritus and algae ingested by Curimatidae were responsible for 46.5% of the FIWCB, while that for algae ingested by Loricariidae (armoured catfish) accounted for 13.2%. The importance of detritus in fish diets is discussed as a strategy for shortening food chains, thereby increasing community efficiency, and as a consequence, fish biomass. It was learnt that the main route of energy flow in this perennial lake was through the detritus chain. The floodplain lakes function as a dry season feeding ground for small-sized species of fish, which are potential prey for the more highly valued larger species of fish.

Relief influence on the spatial distribution of the Atlantic Forest cover on the Ibiúna Plateau, SP

Several studies suggest that, on a large scale, relief conditions influence the Atlantic Forest cover. The aim of this work was to explore these relationships on a local scale, in Caucaia do Alto, on the Ibiúna Plateau. Within an area of about 78 km2, the distribution of forest cover, divided into two successional stages, was associated with relief attribute data (slope, slope orientation and altitude). The mapping of the vegetation was based on the interpretation of stereoscopic pairs of aerial photographs, from April 2000, on a scale of 1:10,000, while the relief attributes were obtained by geoprocessing from digitalized topographic maps on a scale of 1:10,000. Statistical analyses, based on qui-square tests, revealed that there was a more extensive forest cover, irrespective of the successional stage, in steeper areas (>10 degrees) located at higher altitudes (>923 m), but no influence of the slope orientation. There was no sign of direct influence of relief on the forest cover through environmental gradients that might have contributed to the forest regeneration. Likewise, there was no evidence that these results could have been influenced by the distance from roads or urban areas or with respect to permanent preservation areas. Relief seems to influence the forest cover indirectly, since agricultural land use is preferably made in flatter and lower areas. These results suggest a general distribution pattern of the forest remnants, independent of the scale of study, on which relief indirectly has a strong influence, since it determines human occupation.

A human retrieval study of plasma-sprayed hydroxyapatite-coated plateau root form implants after 2 months to 13 years in function

Calcium phosphate-based bioactive ceramics in various physical and chemical formulations have been extensively utilized as biomaterials for bone regeneration/conduction. However, the determination of their in vivo temporal behavior from the short to long term in humans has been a challenge due to the lack of physical reference for morphologic and morphometric evaluation. The present study evaluated bone morphology and morphometry (bone-to-implant contact [BIC]) around plasma-sprayed hydroxyapatite (PSHA)-coated endosseous implants that were retrieved due to prosthetic reasons while successfully in function at the posterior region of the jaws from as early as 2 months to ~13 years after a 6-month healing period after placement. Bone morphology was evaluated by light microscopy, and BIC was determined using computer software. Irrespective of the time in vivo, lamellar bone was observed in close contact with the implant PSHA-coated surface and between plateaus. BIC ranged from ~35-95%, was highly directional, and Haversian-like osteonic morphology between plateaus was observed for most implants. The PSHA coating was present with little variation in thickness between the samples retrieved regardless of time in vivo. © 2010 by Begell House, Inc.

Piscicultura e manejo da qualidade da água

Fish farms' water quality management is analyzed with regard to the management employed and the different trophic states are compared within the system during the dry and rainy seasons. Six sites were marked two in the water supply (P1 and P2), and four within the fish farm (P3 to P6). Whereas sites P1 and P2 (water supply) were characterized as oligotrophic, the others were mesotrophic and eutrotrophic sites. Environmental variables, mainly nutrients, conductivity, COD, BOD5 and TSS tended to increase as from P3 due to management and fertilization. Greater impact has been registered in the fish farm under analysis for variables COD, ammonia, total phosphorus and TSS during the discharge and pond emptying period. Frequent monitoring of water quality should be undertaken in fish breeding and plankton production ponds, especially in those close to P3 and P4. Removal of sediment in decantation lake or P5 is also recommended to decrease nutrient concentrations, especially phosphorus, accumulated on the bottom soil.

Diversity of leaf-litter anurans in a fragmented landscape of the Atlantic Plateau of Sao Paulo State, southeastern Brazil

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

Modelling the surface circulation and thermal structure of a tropical reservoir using three-dimensional hydrodynamic lake model and remote-sensing data

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

NDVI and vegetation phenology dynamics under the influence of sunshine duration on the Tibetan plateau

Climate change has significantly influenced vegetation dynamics on the Tibetan Plateau (TP). Past research mainly focused on vegetation responses to temperature variation and water stress, but the influence of sunshine duration on NDVI and vegetation phenology on the TP is not well understood. In this study, NDVI time series from 1982-2008 were used to retrieve spatiotemporal vegetation dynamics on the TP. Empirical orthogonal function (EOF) analysis was conducted to understand the spatiotemporal variations of NDVI. The Start of Season (SOS) was estimated from NDVI time series with a local threshold method. The first EOF, accounting for 35.1% of NDVI variations on the TP, indicates that NDVI variations are larger in areas with shorter sunshine duration. The needle-leaved forest and shrub in the southeastern TP are more sensitive to sunshine duration anomalies (p < 0.01) than broad-leaved forest, steppe, and meadow due to spatial and altitudinal distribution of sunshine duration and vegetation types. The decrease in sunshine duration for the growing season on the TP has resulted in a decreased NDVI trend in some areas of southeastern TP (p ranging from 0.32-0.05 with threshold ranging from 0.05 to 0.25) in spite of the overall NDVI increase. SOS dynamics in most parts of the TP were mainly related to temperature variability, with precipitation and sunshine duration playing a role in a few regions. This study enhances our understanding of vegetation responses to climatic change on the TP.

A new species of the oligotrophic genus ochroconis (Sympoventuriaceae)

Ochroconis globalis, a novel species of the melanized genus Ochroconis (Sympoventuriaceae, Venturiales), is described and illustrated and distinguished phenotypically and molecularly from existing ochroconis-like species. Phylogenetic analyses using nuclear ribosomal DNA genes (nuSSU, ITS, nuLSU) and coding gene fragments (ACT1, BT2, TEF1) revealed clustering of all strains as a monophyletic clade which was well separated from known Ochroconis species. Most strains of the new species were obtained from human-made environments, while the natural habitat of the species remains enigmatic. The new combination Ochroconis musae is introduced for one of the most commonly encountered Ochroconis species, and a phenotypic key to all species is provided.