Ecological strategies of Al-accumulating and non-accumulating functional groups from the cerrado sensu stricto

Coordenação de Aperfei çoamento de Pessoal de Nível Superior (CAPES)

Diversity of functional traits of fleshy fruits in a species-rich Atlantic rain forest

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

Reduction of mercury(II) by tropical river humic substances (Rio Negro) - Part II. Influence of structural features (molecular size, aromaticity, phenolic groups, organically bound sulfur)

The influence of structural features of tropical river humic substances (HS) on their capability to reduce mercury(II) in aqueous solutions was studied. The HS investigated were conventionally isolated from Rio Negro water-Amazonas State/Brazil by means of the collector XAD 8. In addition, the isolated HS were on-line fractionated by tangential-flow multistage ultrafiltration (nominal molecular-weight cut-offs: 100, 50, 30, 10, 5 kDa) and characterized by potentiometry and UV/VIS spectroscopy. The reduction of Hg(II) ions to elemental Hg by size-fractions of Rio Negro HS was assessed by cold-vapor AAS (CVAAS). UV/VIS spectrometry revealed that the fractions of high molecular-size (F-1 > 100 kDa and F-2: 50-100 kDa) have a higher aromaticity compared to the fractions of small molecular-size (F-5: 5-10 kDa, F-6: < 5 kDa). In contrast, the potentiometric study showed different concentration of functional groups in the studied HS fractions. The reduction of Hg(II) by aquatic HS fractions at pH 5 proceeded in two steps (I, II) of slow first order kinetics (t(1/2) of I: 160 min, t(1/2) of II: 300 min) weakly influenced by the molecular-size, in contrast to the differing degree of Hg(II) reduction (F-5 > F-2 > > F-1 > F-3 > F-4 > > F-6). Accordingly, Hg(II) ions were preferably reduced by HS molecules having a relatively high ratio of phenolic/carboxylic groups and a small concentration of sulfur. From these results a complex 'competition' between reduction and complexation of mercury(II) by aquatic HS occurring in tropical rivers such as the Rio Negro can be suggested. (C) 2003 Elsevier B.V. All rights reserved.

Functional and Taxonomic Diversity of Stinging Wasps in Brazilian Atlantic Rainforest Areas

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

Abundance of sedentary consumers and sessile organisms along the wave exposure gradient of subtropical rocky shores of the south-west Atlantic

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

What Role Should Government Regulation Play in Ecological Restoration? Ongoing Debate in São Paulo State, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thermal analysis characterization of PAAm-co-MC hydrogels

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Foraging by the omnivorous crab Pachygrapsus transversus affects the structure of assemblages on sub-tropical rocky shores

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

Ultrastructure of the intramandibular gland of workers and queens of the stingless bee, Melipona quadrifasciata

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

Short-term changes caused by fire and mowing in Brazilian Campos grasslands with different long-term fire histories

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Using network connectance and autonomy analyses to uncover patterns of photosynthetic responses in tropical woody species

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

Analysis of Ant Communities Comparing Two Methods for Sampling Ants in an Urban Park in the City of São Paulo, Brazil

This study aimed to analyze the species composition and functional groups of the ant community and to assess the efficiency of two sampling methods, pitfall and leaf litter sampling, in an urban park. A total of 1,401 ants were collected, which belonged to six subfamilies and 36 species. The predominant species was Wasmannia auropunctata (present in 45.36% of the samples), while the functional group of opportunistic ants were the most frequent (present in 83.75% of the samples) and abundant (95.29% of the total collected specimens) functional group. The Jaccard Similarity Index showed a low similarity between the two sampling methods, as the difference of the number of individuals for each species between these two methods was not significant in only one case (Linepithema sp. 1, p = 0.4561). The fungus-growing and cryptic ants were more collected in leaflitter samples (p<0.0001; p = 0.0348 respectively). Although there was no significant difference (p = 0.6397) between the two sampling methods for the total individuals of opportunistic ants, more species of this group were collected in pitfall traps. This difference was not significant because of the high presence of W. auropunctata, an opportunistic ant, in samples of leaf litter. Due to the predominance of tramp ants in the studied area, this article illustrates the importance of green urban areas in ant control strategies, since these sites could be used as a source of new colonization for these ants. Furthermore, the combination of the two sampling methods seems to be complementary for obtaining a more complete picture of the ant community.

The fish zonation of the Itanha,m river basin in the Atlantic Forest of southeast Brazil

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

Birds and bats diverge in the qualitative and quantitative components of seed dispersal of a pioneer tree

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Distribuição de metais e caracterização das constantes de troca entre espécies metálicas e frações húmicas aquáticas de diferentes tamanhos moleculares

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