Composition, structure and floristic diversity in dense rain forest in the Eastern Amazon, Amapá, Brazil / Composição, estrutura e diversidade florística em floresta ombrófila densa na Amazônia Oriental, Amapá, Brasil

This study aims to evaluate the phytosociology and floristic composition of tree species in the eastern Amazon, at the Iratapuru River Sustainable Development Reserve (RDS), State of Amapá. Fouteen quarters with dimensions of 100 m x 100 m were randomly inventoried, and 50 sub-plots of 10 m x 20 m were established. In each sub-plot all living individuals were sampled, being taken from the height data and DAP (breast height diameter) for tree species ≥ 10 cm. A total of 5,233 individuals belonging to 33 families and 184 species were registered. The families with the largest number of species were Fabaceae (32), Lauraceae (17), Sapotaceae (12), Moraceae (10), Lecythidaceae (8) and Annonaceae (8). The six most abundant families (18.18% of total families) in the present study were responsible for more than half (57.92%) of the total number of species. The floristic structure of the area studied was diverse, with species of varied interests, including: medicinal, timber and oil-producing.

Este trabalho objetiva avaliar a composição florística e a fitossociologia de espécies arbóreas na Amazônia Oriental, Reserva de Desenvolvimento Sustentável do Rio Iratapuru, Estado do Amapá. Foram inventariados 14 quadrantes de 100 m x 100 m distribuídos aleatoriamente, onde se estabeleceram 50 sub-parcelas de 10 m x 20 m. Em cada sub-parcela foram amostrados todos os indivíduos vivos, sendo tomados dados de altura e DAP (diâmetro a altura do peito) para espécies arbóreas ≥10 cm. Foram registrados 5.233 indivíduos distribuídos em 33 famílias e 184 espécies. As famílias com maior número de espécies foram Fabaceae (17), Lauraceae (17), Sapotaceae (12), Moraceae (10), Lecythidaceae (8) e Annonaceae (8). Essas seis famílias mais abundantes (18,18% total das famílias) presentes no estudo foram responsáveis por mais da metade (57,92%) do número total de espécies. A estrutura florística da área estudada mostrou-se diversificada, apresentando espécies de interesses variados, como medicinal, madeireira e oleífera.

Coastal bacterioplankton community diversity along a latitudinal gradient in Latin America by means of V6 tag pyrosequencing.

The bacterioplankton diversity of coastal waters along a latitudinal gradient between Puerto Rico and Argentina was analyzed using a total of 134,197 high-quality sequences from the V6 hypervariable region of the small-subunit ribosomal RNA gene (16S rRNA) (mean length of 60 nt). Most of the OTUs were identified into Proteobacteria, Bacteriodetes, Cyanobacteria, and Actinobacteria, corresponding to approx. 80% of the total number of sequences. The number of OTUs corresponding to species varied between 937 and 1946 in the seven locations. Proteobacteria appeared at high frequency in the seven locations. An enrichment of Cyanobacteria was observed in Puerto Rico, whereas an enrichment of Bacteroidetes was detected in the Argentinian shelf and Uruguayan coastal lagoons. The highest number of sequences of Actinobacteria and Acidobacteria were obtained in the Amazon estuary mouth. The rarefaction curves and Good coverage estimator for species diversity suggested a significant coverage, with values ranging between 92 and 97% for Good coverage. Conserved taxa corresponded to aprox. 52% of all sequences. This study suggests that human-contaminated environments may influence bacterioplankton diversity.