Uranium speciation in groundwaters from Parana basin, Brazil

This paper describes the results of a regional study involving the sampling of 60 pumped tubular wells drilled at the Parana sedimentary basin, Brazil, which was carried out with the purpose of evaluating the U speciation in the Botucatu-Piramboia aquifer. Uranium proved to be intensively dissolved even under the enhanced reducing conditions occurring at the most confined zones of the aquifer, and Eh-pH diagrams were utilized to evaluate the influence of temperature and pressure on the migration of the U-species within the aquifer.

Dissolved radioelements in (oil) water wells in Parana basin, Brazil

This paper describes the results of a study on groundwaters from Tubarao Group at the Parana sedimentary basin, São Paulo State, Brazil. The purpose of this study was to integrate chemical and U-isotopes data in order to evaluate the models for quantifying different relative volumes of mixing waters in a resultant water. Despite it was possible to generate a typical triangle involving U-238 and its daughter U-234, the U-isotopes model failed to interpret the major hydrochemical facies observed in the studied localities.

The use of U-isotopes on the study of a weathered cover in Parana basin, Brazil

This paper describes the results of a study involving the sampling of a soil profile developed over sandstone from Itarare Sub-Group at the Parana sedimentary basin, Brazil. It was carried out to integrate chemical and U-isotopes data in order to improve the knowledge of the weathering processes acting in the area. U-238 and its daughter U-234 proved to be important tools for evaluating physical and chemical alteration, allowing to suggest a possible timescale for the development of the more superficial soil horizons.

Hydrochemical and stable isotopes (H, O, S) signatures in deep groundwaters of Parana basin, Brazil

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

DISTRIBUTION OF CAPYBARAS IN AN AGROECOSYSTEM, SOUTHEASTERN BRAZIL, BASED ON ECOLOGICAL NICHE MODELING

Southeastern Brazil has seen dramatic landscape modifications in recent decades, due to expansion of agriculture and urban areas; these changes have influenced the distribution and abundance of vertebrates. We developed predictive models of ecological and spatial distributions of capybaras (Hydrochoerus hydrochaeris) using ecological niche modeling. Most Occurrences of capybaras were in flat areas with water bodies Surrounded by sugarcane and pasture. More than 75% of the Piracicaba River basin was estimated as potentially habitable by capybara. The models had low omission error (2.3-3.4%), but higher commission error (91.0-98.5%); these ""model failures"" seem to be more related to local habitat characteristics than to spatial ones. The potential distribution of capybaras in the basin is associated with anthropogenic habitats, particularly with intensive land use for agriculture.

Determination of heavy metals by inductively coupled plasma-optical emission spectrometry in fish from the Piracicaba River in Southern Brazil

A total of 202 fish, representing 16 species, were collected during 2008 (March-October) in the Tanquan region of the Piracicaba River using nets. Flesh samples were collected and analyzed, using inductively coupled plasma-optical emission spectroscopy for Al, As, Cd, Co Cr, Cu, Mn, Mo, Ni, Ph, Se, Sn, Sr, and Zn. The results showed that the flesh of these fish all contained extremely high levels of Al and Sr, and moderately high levels of Cr, As, Zn, Ni. Mn and Pb. The metals were higher in these fish during rainy season, with fish collected during the months of March and October being the highest. In addition, the accumulation of metals was species-dependent. Cascudos (Hypostomus punctatus) and piranhas (Serrasalmus spilopleura) exhibited high levels of almost all of the metals, while curimbata (Prochilodus lineatus) had moderate levels. A few species, including pacu (Piaractus mesopotamicus) and dourado (Salminus maxillosus), had very low levels of most metals. The results show that the Piracicaba River Basin is widely contaminated with high levels of many toxic heavy metals, and that human consumption of some fish species is a human health concern. (C) 2009 Elsevier B.V. All rights reserved.

Peacock bass mortality associated with catch-and-release sport fishing in the Negro River, Amazonas State, Brazil

Sport fishing for peacock bass Cichla spp. in the Brazilian Amazon has increased in popularity and attracts anglers who generate significant economic benefits in rural regions. The sustainability of this fishery is partly dependent on the survival of fish caught through catch-and-release fishing. The objective of this work was to investigate, hooking mortality of Cichla spp., including speckled peacock bass (C. temensis Humbolt), butterfly peacock bass (C. orinocensis Humbolt), and popoca peacock bass (C. monoculus Agassiz) in the basin of the Negro River, the largest tributary of the Amazon River. Fish were caught at two different sites using artificial lures, transported to pens anchored in the river and monitored for 72 hours. A total of 162 individual peacock bass were captured and hooking mortality (mean % ± 95% confidence intervals) was calculated. Mean mortality was 3.5% (± 5.0), 2.3% (± 3.5) and 5.2% (± 10.2) for speckled peacock bass, butterfly peacock bass, and popoca peacock bass, respectively. Lengths of captured fish ranged from 26 to 79 cm (standard length), however, only fish under 42 cm died. This research suggests that catch-and-release sport fishing of peacock bass does not result in substantial mortality in the Negro River basin.

Diet of Iheringichthys labrosus (Siluriformes, Pimelodidae) in the Ibicuí River, Southern Brazil

The diet of the benthic-feeding fish Iheringichthys labrosus (Lütken, 1874) was analyzed. Samples were taken bimonthly from December 1999 to January 2002, in three sites of the Ibicuí River, a tributary of Uruguay River basin (Rio Grande do Sul, Brazil). In each sampling point the specimens were collected in lentic and lotic environments. Gillnets and trammel nets were examined every 6 hours (6h, 12h, 18h and 24h). Diet description was based on the frequency of occurrence and the volume of each food item to obtain the Alimentary Index (IAi). The average stomach fullness was adopted to detect variations in the feeding activity according to the season, the circadian rhythm and the environment. Chironomids were the most important food item, followed by mollusks, and feeding activity was highest in summer, during daylight (6h and 12h), and in the lotic environment of the second sampling point.

Susceptibility and compatibility of Biomphalaria tenagophila from the Río de la Plata basin with Schistosoma mansoni from Brazil

Schistosomiasis has expanded to southern parts of Brazil. Between 2005-2007 the dispersion and the proliferation of Biomphalaria tenagophila was verified in the province of Corrientes near the Brazilian border. In order to study the possibility that schistosomiasis might spread into the basins of the Paraná and Uruguay Rivers, 440 B. tenagophila collected from 10 populations groups were experimentally exposed to infection with Schistosoma mansoni of the SJ2 strain. Snails from five localities were susceptible. Frandsen's index (TCP/100) shows that those snails from Mirungá (11%), Aguacerito (2%) and Curupicay (2%) were Class I and not very compatible. Meanwhile, snails from Copra (6%) and Pay-Ubre (22%), in the Paraná River basin, were Class II and poorly compatible.

Crepuscular activity of culicids (Diptera, Culicidae) in the peridomicile and in the remaining riparian forest in Tibagi river, State of Paraná, Brazil

Crepuscular activity of culicids (Diptera, Culicidae) in the peridomicile and in the remaining riparian forest in Tibagi river, State of Paraná, Brazil. Human-attracted mosquitoes were collected for one hour, around sunset time (half hour before and half after), from April to December 2006, in two environments (riparian forest and near houses), in Tibagi river basin, Palmeira municipality, State of Paraná. Seven-hundred forty-nine mosquitoes, belonging to 13 species, were collected. Psorophora champerico Dyar & Knab, 1906 (42.86%) and Psorophora discrucians (Walker, 1856) (40.59%) were the most frequent species. No significant differences between quantities of Ps. champerico (t = -0.792; d.f. = 16; p = 0.43) and Ps. discrucians (t = 0.689; d.f. = 16; p = 0.49) obtained in riparian forest and near houses were observed, indicating similar conditions for crepuscular activity of these species in both environments. Psorophora champerico and Ps. discrucians responded (haematophagic activity) to environmental stimuli associated with the twilight hours differently in distinct habitats studied. The former species is registered for the first time in the Atlantic forest biome.

A comparative study of four tree species used in riparian forest restoration along Uruguay River, Brazil

Silvicultural and ecological knowledge about tree species is basic to restoration planning, particularly in high diversity regions. Here we present a comparison of four native tree species from the middle Uruguay River basin, Brazil-Argentine frontier: Heliocarpus americanus L. (Malvaceae), Maclura tinctoria (L.) D. Don ex Steud. (Moraceae), Schinus terebinthifolius Raddi (Anacardiaceae) and Cordia trichotoma (Vell.) Arrab. ex Steud. (Boraginaceae). We obtained data on initial growth, light interception, litterfall and litter mineral contents. H. americanus presented the greatest height and the lowest value of height/crown width ratio. H. americanus and M. tinctoria presented the highest light interception rate (>94 %) and highest litterfall (879 ± 151 and 792 ± 164 g·m-2·year-1, respectively). For the set of species, the lowest litterfall occurred between July and September. H. americanus presented the highest K concentration (1.13%) in the litter, while C. trichotoma had the highest values of Ca and Mg (6.35 and 2.02 %, respectively). S. terebinthifolius had the lowest light interception rate and litter mineral content.

Small mammals of the mid-Araguaia River in central Brazil, with the description of a new species of climbing rat

The mid-Araguaia River basin in central Brazil is considered a priority area for biodiversity conservation, and Parque Estadual do Cantao (PEC) is one of the most important protected areas in this ecotone between Cerrado and Amazonia. This area suffers an intensive human pressure with high rates of deforestation, and still remains poorly studied in terms of biodiversity. From June 2007 to November 2008 we sampled small mammals from both banks of the mid-Araguaia River, in the states of Tocantins and Para. Data are given about morphological traits, geographic distribution and natural history of 22 species of small non-volant mammals (eight marsupials and 14 rodents) surveyed at PEC and its surroundings. We also present mitochondrial phylogenetic analyses that allow species identification within the genera: Oecomys, Oligoryzomys and Rhipidomys, and delineate an undescribed species of Thrichomys. Based on morphologic and molecular data, we describe a new species of Rhipidomys previously assigned to R. nitela, which is apparently endemic to the Araguaia-Tocantins basin in the Cerrado. Additionally, our phylogenetic analyses provide support for the role played by the Araguaia River as an important geographic barrier for two sister species of Rhipidomys.

Phylogeography and Pleistocene demographic history of the endangered marsh deer (Blastocerus dichotomus) from the Rio de la Plata Basin

The marsh deer is the largest neotropical cervid with morphological and ecological adaptations to wetlands and riparian habitats. Historically, this now endangered species occupied habitats along the major river basins in South America, ranging from southern Amazonia into northern Argentina to the Parana river delta. This particularly close association with wetlands makes marsh deer an excellent species for studying the effects of Pleistocene climatic changes on their demographic and phylogeographic patterns. We examined mitochondrial DNA variation in 127 marsh deer from 4 areas distributed throughout the Rio de]a Plata basin. We found 17 haplotypes in marsh deer from Brazil, Bolivia and Argentina that differed by 1-8 substitutions in a 601 bp fragment of mitochondrial control region sequence, and 486 bp of cytochrome b revealed only 3 variable sites that defined 4 haplotypes. Phylogeny and distribution of control region haplotypes suggest that populations close to the Pantanal area in central Brazil underwent a rapid population expansion and that this occurred approximately 28,000-25,000 years BP. Paleoclimatic data from this period suggests that there was a dramatic increase for precipitation in the medium latitudes in South America and these conditions may have fostered marsh deer's population growth.

Seasonality of macroalgal communities in a subtropical drainage basin in Paraná state, southern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Detection of hybrids and genetic introgression in wild stocks of two catfish species (Siluriformes: Pimelodidae): The impact of hatcheries in Brazil

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