AMS and grain shape fabric of the Late Palaeozoic diamictites of the Southeastern Paran Basin, Brazil

Diamictites interbedded with marine shales and turbidites onlap the eastern border of the Parana Basin (Southern Brazil). These poorly sorted sediments were deposited during the Permo-Carboniferous glaciation, and their matrix-supported clasts show no preferred orientation. These massive rocks have been studied using anisotropy of magnetic susceptibility (AMS) and grain shape fabric. Hysteresis loops and thermomagnetic measurements show that AMS depends mostly on the paramagnetic clays, but fine ferromagnetic particles also contribute to the anisotropy. The coarse silt to sand grain preferred orientation study supports the use of AMS in describing the diamictite fabric, at least regarding the orientation of the foliation. AMS and grain shape data reveal subhorizontal to weakly inclined magnetic and grain shape foliation parallel to the regional bedding. The magnetic lineations are normally scattered within the foliation plane in agreement with the oblate AMS ellipsoids found in these rocks. Both fabric patterns are consistent with deposition by subaqueous mudflows that were resedimented downslope, with elastic supply from continental sources. The off-vertical grain shape foliation poles suggest that the deposition of diamictites was controlled by the depocentre topography of the Rio do Sul sub-basin.

First record of petrified Permian pecopterids from the Parana Basin, Brazil (Corumbatai Formation, Passa Dois Group, northeastern State of São Paulo): Morphology, anatomy and paleoecological implications

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

Natural Conditions and Environmental Impacts in a Coastal Hydrographic Basin in the Brazilian Amazon

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Microfacies and sequence stratigraphy of the Amapa Formation, Late Paleocene to Early Eocene, Foz do Amazonas Basin, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Moenkhausia celibela: a new species from the Amazon basin, Brazil (Characiformes: Characidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anthropogenic influences on annual flux of cations and anions at meio stream basin, São Paulo State, Brazil

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

Othonella araguaiana (Bivalvia, Megadesmidae) from the Corumbatai Formation (Midlle [Middle] Permian), Eastern Margin of the Parana Basin: systematic, evolutionary and biostratigraphic significances.

In this study, the occurrence of Othonella araguaiana Mendes, a rare bivalve species is reported for the first time in the Pinzonella illusa biozone, Middle Permian Corumbatai Formation, in the State of São Paulo. This species was originally described in coeval rocks of the Estrada Nova Formation (= Corumbatai) from the Alto Araguaia and Alto Garcas regions, State of Mato Grosso. The specimens of O. araguaiana were found in the base of a bioclastic sandstone bed, a proximal tempestite, in the middle of the Corumbatai Formation, in the city of Rio Claro, São Paulo State. The silicified shells and internal molds are well preserved, showing impressions of muscle scars and other internal anatomic characters (e.g., hinge), never illustrated by previous authors. In his original description, Mendes (1963) called attention to the similarity between O. araguaiana and Terraia aequilateralis, a common veneroid of the Corumbatai Formation. Conversely, Runnegar and Newell (1971) suggested that O. araguaiana belongs to Megadesmidae, being a junior synonym of Plesiocyprinella carinata (the commonest megadesmid of the Passa Dois Group). Our study indicates that O. araguaiana is indeed a megadesmid, but is distinct from the P. carinata. The new occurrence of O. araguaiana demonstrates that a) the paleobiogeographic distribution of this species is wider than previously thought (that it was restricted to the northern part of Parana Basin, Mato Grosso State); b) the molluscan fauna of the Corumbatai Formation (P. illusa biozone) in the State of São Paulo is more diverse and dominated by megadesmids; and c) the composition of the molluscan fauna of the Corumbatai Formation in Alto GarYas, State of Mato Grosso, is essentially the same as that of the P. illusa biozone of the eastern margin of the Parana Basin.

Three new species of Neoplecostomus (Teleostei: Siluriformes: Loricariidae) from the Upper Rio Parana basin of southeastern Brazil

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

Leaiid conchostracans from the uppermost Permian strata of the Parana Basin, Brazil: Chronostratigraphic and paleobiogeographic implications

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Widespread Amazon forest tree mortality from a single cross-basin squall line event

Climate change is expected to increase the intensity of extreme precipitation events in Amazonia that in turn might produce more forest blowdowns associated with convective storms. Yet quantitative tree mortality associated with convective storms has never been reported across Amazonia, representing an important additional source of carbon to the atmosphere. Here we demonstrate that a single squall line (aligned cluster of convective storm cells) propagating across Amazonia in January, 2005, caused widespread forest tree mortality and may have contributed to the elevated mortality observed that year. Forest plot data demonstrated that the same year represented the second highest mortality rate over a 15-year annual monitoring interval. Over the Manaus region, disturbed forest patches generated by the squall followed a power-law distribution (scaling exponent alpha = 1.48) and produced a mortality of 0.3-0.5 million trees, equivalent to 30% of the observed annual deforestation reported in 2005 over the same area. Basin-wide, potential tree mortality from this one event was estimated at 542 +/- 121 million trees, equivalent to 23% of the mean annual biomass accumulation estimated for these forests. Our results highlight the vulnerability of Amazon trees to wind-driven mortality associated with convective storms. Storm intensity is expected to increase with a warming climate, which would result in additional tree mortality and carbon release to the atmosphere, with the potential to further warm the climate system. Citation: Negron-Juarez, R. I., J. Q. Chambers, G. Guimaraes, H. Zeng, C. F. M. Raupp, D. M. Marra, G. H. P. M. Ribeiro, S. S. Saatchi, B. W. Nelson, and N. Higuchi (2010), Widespread Amazon forest tree mortality from a single cross-basin squall line event, Geophys. Res. Lett., 37, L16701, doi:10.1029/2010GL043733.

Fish Migration, Dams, and Loss of Ecosystem Services in the Mekong Basin

The past decade has seen increased international recognition of the importance of the services provided by natural ecosystems. It is unclear however whether such international awareness will lead to improved environmental management in many regions. We explore this issue by examining the specific case of fish migration and dams on the Mekong river. We determine that dams on the Mekong mainstem and major tributaries will have a major impact on the basin's fisheries and the people who depend upon them for food and income. We find no evidence that current moves towards dam construction will stop, and consider two scenarios for the future of the fisheries and other ecosystems of the basin. We conclude that major investment is required in innovative technology to reduce the loss of ecosystem services, and alternative livelihood strategies to cope with the losses that do occur.

A stratigraphic chart of the Late Carboniferous/Permian succession of the eastern border of the Parana Basin, Brazil, South America

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fish, Tatui river basin, state of São Paulo, Brazil.

The Tatui river hydrographic basin locates in low Sorocaba river basin in São Paulo state, Brazil. A relatively high diversity of fish species was noticed at that place, whose habitats are also presumed to be diversified. The Tatui river is an important tributary of Sorocaba river, with great number of smaller streams and marginal lagoons. Fishes were collected using gill-nets, purse seines, sieves and traps, line and hook, every month during one year (from May 2009 to April 2010). Fish species were 51, including seven orders and 18 families. Characiformes and Siluriformes were the most represented with respectively 26 and 14 species.

Spontaneous triploidy and NOR activity in Eigenmannia sp. (Pisces, Sternopygidae) from the Amazon basin

The occurrence of a natural triploid among diploid individuals of Eigenmannia sp from the Amazon basin is described. The diploid individuals had 2n=31 and 32 chromosomes, the difference in chromosome number being due to a Robertsonian rearrangement. The triploid individual presented 2n=46 and had two fused acrocentrics. NOR activity was present in the three homologues of triploid and a NOR polymorphism was detected in the triploid and diploids. © 1985 Dr W. Junk Publishers.

Life strategies of some long-distance migratory catfish in relation to hydroelectric dams in the Amazon Basin

In this paper, we present evidence that the long-distance migratory catfish Brachyplatystoma filamentosum, B. flavicans, B. vaillantii, Goslinia platynema and Lithodoras dorsalis spawn in the headstreams of the Amazon river and its tributaries and that the estuary of the Amazon is the main nursery ground utilized by their alevins. The impact of hydroelectric dams on their populations are discussed in terms of interruption to fish migration routes up river and to larvae moving down river, provided that the hypothesis above holds. Ways of mitigating the impact are also considered. © 1991.