Bárbara Medeiros Fonseca

Biovolume de cianobactérias e algas de reservatórios tropicais do Brasil com diferentes estados tróficos

Biovolume of Cyanobacteria and algae from Brazilian tropical reservoirs with different trophic status). The present study aimed at presenting the biovolume of planktonic and periphytic cyanobacteria and algae from reservoirs with different trophic status at Parque Estadual das Fontes do Ipiranga, Sao Paulo, Sao Paulo State, Brazil. The study includes a proposal for determining the biovolume of colonial forms of Cyanobacteria such as Microcystis and Sphaerocavum. The list of biovolume will contribute to algal ecology studies, allowing the application of this information to research in this area of knowledge, besides serving as a comparative model for other tropical ecosystems. The list comprises the biovolume of 568 taxa, including information on their taxonomic classes, maximum linear dimension and surface/volume ratio.

Desmídias perifíticas de cinco lagoas do Distrito Federal, Brasil: I - Gênero Cosmarium Corda ex Ralfs

This study aimed a taxonomic survey on genus Cosmarium in five oligotrophic lagoons in the Federal District, Brazil: Lagoa Bonita, Lagoa Joaquim Medeiros, Lagoa do Cedro, Lagoa Taquara and Lagoa dos Gansos. Samples were realized between 2006 and 2009, by macrophytes squeezing and/or submerged substrates scraping; 18 samples were analyzed and deposited at the Herbarium of the University of Brasilia. They were fixed in formalin solution (4%) and analized under 400× and 1000× magnification. Altogether 42 taxons were found. Among them, 30 are cited for the first time in the Federal District and probably eight for Brazil. Lagoa Bonita had the higher number of taxa (32), followed by Lagoa Joaquim Medeiros (19), Lagoa do Cedro (16), Lagoa dos Gansos (15) e Lagoa Taquara (9). Cosmarium pseudopyramidatum var. pseudopyramidatum Lundell was the most common taxon, present in 100% of the samples.

Biodiversity in Pristine Wetlands of Central Brazil: a Multi-Taxonomic Approach

This study main goal was to characterize biodiversity in tropical pristine wetlands of two protected areas from central Brazil under a multi-taxonomic approach, with special interest on the distribution and identity of those taxa that most represent these reference conditions. Samplings were conducted during dry and rainy seasons (2009), in nine wetlands. We reported 114 herbaceous macrophytes, 334 algae/cyanobacteria, 45 microcrustaceans and 139 testate amoebae. Macrophytes presented the highest beta diversity compared to the other groups (βw = 3.2), while microcrustaceans showed the lowest one (βw = 1.4). The microorganism diversity associated with the dominating emergent macrophytes (e.g., Poaceae and Cyperaceae) was mainly composed of zygnematophycean algae, branched heterocytous cyanobacteria, along with Chydoridae (Cladocera) and Cyclopoida (Copepoda) microcrustaceans and Lesquereusiidae testate amoebae. Many tropical rare/endemic taxa were reported, e.g., among genera Parallela (green algae), Placocista and Quadrulella (testate amoebae), Celsinotum, Ephemeroporus, Metacyclops and Paracyclops (microcrustaceans); also, the genus Paralimnetis (Laevicaudata) is cited for the first time in Brazil. These findings reinforce these small wetlands as potential biodiversity hotspots and stepping stones for dispersing organisms. Finally, the presence of temporary environments among Cerrado wetlands may contribute as an additional beta diversity driver that deserves more attention in future studies.

Desmídias perifíticas de cinco lagoas do Distrito Federal, Brasil: II - Gêneros Euastrum Ehrenberg ex Ralfs, Micrasterias C. Agardh ex Ralfs e Triploceras Bailey

Este estudo teve como objetivo realizar o levantamento taxonomico dos generos Euastrum, Micrasterias e Triploceras de cinco lagoas oligotroficas do Distrito Federal: Lagoa Bonita, Lagoa Joaquim Medeiros, Lagoa do Cedro, Lagoa Taquara e Lagoa dos Gansos. As coletas foram realizadas entre 2006 e 2009, por meio do espremido de macrofitas e/ou raspagem de substratos submersos, num total de 18 amostras depositadas no Herbario da Universidade de Brasilia. O material coletado foi fixado em formalina a 4% e analisado sob aumentos de 400×x e 1000×. Este estudo registrou 13 taxons de Euastrum, onze de Micrasterias e um de Triploceras . Desses, 12 sao citacoes pioneiras para o Distrito Federal (nove Euastrum e tres Micrasterias ). A Lagoa dos Gansos se destacou pela maior riqueza entre as lagoas. Euastrum brasiliense var. brasiliense Borge foi o taxon mais comum.