Eddy-induced upwelling off Cape Sao Tome (22 degrees S, Brazil)

The regional ocean off southeast Brazil (20 degrees S-28 degrees S) is known as a current-eddy-upwelling region. The proximity of the Brazil Current to the coast in the Cape Sao Tome vicinities, as well as of its quasi-stationary unstable meanders, suggests the possibility of background eddy-induced upwelling. Such phenomenon can intensify the prevalent coastal upwelling due to wind and topographic effects. In this paper, with the help of a numerical simulation, we provide evidence that eddy-induced upwelling in the absence of wind is possible in this region. The simulation was conducted with a regional configuration of the 3-D Princeton Ocean Model initialized by a feature-based implementation of the Brazil Current and Cape Frio eddy, blended with climatology. (C) 2010 Elsevier Ltd. All rights reserved.

Is the Brazil Current eddy-dominated to the north of 20 degrees S?

The Brazil Current (BC) originates with the arrival and bifurcation of the southernmost branch of the South Equatorial Current (sSEC) between 10-20 degrees S. Previous climatological studies showed a stratified sSEC bifurcation and that the resulting southern branch formed a shallow BC - a weak western boundary current. The analysis of three recent synoptic surveys and global model outputs challenge the description of a continuous BC. The sSEC bifurcation signal near the continental margin was unclear in the analyses, and the velocity fields were dominated by mesoscale eddies. Recurrent anticyclones that seemed to be related to the meandering BC led us to construct a picture of a flow strongly influenced by topography and probably very unstable. Given this new emerging scenario, we hypothesize that the Brazil Current is eddy-dominated to the north of 20 degrees S. Citation: Soutelino, R. G., I. C. A. da Silveira, A. Gangopadhyay, and J. A. Miranda (2011), Is the Brazil Current eddy-dominated to the north of 20 S?, Geophys. Res. Lett., 38, L03607, doi:10.1029/2010GL046276.

Synaptolaemus latofasciatus, a new combination for Leporinus latofasciatus Steindachner, 1910 and its junior synonym Synaptolaemus cingulatus Myers and Fernandez-Yepez, 1950 (Characiformes: Anostomidae)

Leporinus latofasciatus was described by Steindachner (1910) on the basis of a single specimen collected in the rio Orinoco, Venezuela. Since then, no other specimen of the species was mentioned in the literature, and the species was only listed in catalogues, eventually mentioned and treated as a ""poorly known"" species, or even omitted in checklists of fishes from Venezuela. During a visit to the fish collection at the Naturhistorisches Museum at Vienna (NMW) to examine all the type specimens of Leporinus, we were able to study the holotype of Leporinus latofasciatus and recognize that the specimen corresponds to the species described by Myers and Fernandez-Yepez (in Myers, 1950) as Synaptolaemus cingulatus. Thus, the latter is a junior synonym of Leporinus latofasciatus and, based on that, Synaptolaemus latofasciatus (Steindachner, 1910) should be the name applied for this taxon, as a new combination. Herein new data on the holotype of Synaptolaemus latofasciatus are presented and compared with previously data from other authors. In addition, illustrations of live specimens are presented as well as new distribution records for the species.

Acúmulo de minerais em Aechmea blanchetiana (Baker) L.B. Smith (Bromeliaceae), contaminadas com zinco em cultivo in vitro

Com o objetivo de estudar a absorção e translocação de Ca, Co, Fe, K e Zn em Aechmea blanchetiana, plantas foram cultivadas in vitro em meios de cultivo contendo concentrações de Zn (0,0; 0,18; 1,8; 18 e 180 mg Zn L-1). Após 16 semanas de cultivo, os sistemas aéreo e radicular foram separados e determinadas à massa seca para massa de matéria seca e para a análise por ativação com nêutrons (AAN). O procedimento consistiu em irradiar amostras e padrões no reator nuclear de pesquisa IEA-R1 por 16 h para análise por espectrometria de raios gama. O controle dos resultados foi avaliado por meio das análises dos materiais de referência certificados, com desvios padrão relativo de 9,1 % e erros inferiores a 12,9 %. Os resultados das determinações dos elementos mostraram que o Zn alterou absorção e translocação de Ca, Co, Fe, K e Zn. A espécie apresentou alta quantidade de Zn nos sistemas aéreo e radicular indicando, possivelmente, ser bioacumuladora desse elemento.

What drives the seasonality of photosynthesis across the Amazon basin? A cross-site analysis of eddy flux tower measurements from the Brasil flux network

We investigated the seasonal patterns of Amazonian forest photosynthetic activity, and the effects thereon of variations in climate and land-use, by integrating data from a network of ground-based eddy flux towers in Brazil established as part of the ‘Large-Scale Biosphere Atmosphere Experiment in Amazonia’ project. We found that degree of water limitation, as indicated by the seasonality of the ratio of sensible to latent heat flux (Bowen ratio) predicts seasonal patterns of photosynthesis. In equatorial Amazonian forests (5◦ N–5◦ S), water limitation is absent, and photosynthetic fluxes (or gross ecosystem productivity, GEP) exhibit high or increasing levels of photosynthetic activity as the dry season progresses, likely a consequence of allocation to growth of new leaves. In contrast, forests along the southern flank of the Amazon, pastures converted from forest, and mixed forest-grass savanna, exhibit dry-season declines in GEP, consistent with increasing degrees of water limitation. Although previous work showed tropical ecosystem evapotranspiration (ET) is driven by incoming radiation, GEP observations reported here surprisingly show no or negative relationships with photosynthetically active radiation (PAR). Instead, GEP fluxes largely followed the phenology of canopy photosynthetic capacity (Pc), with only deviations from this primary pattern driven by variations in PAR. Estimates of leaf flush at three