Título:	Caracterização sazonal de comunidades de Bacteria e Archaea em sedimentos de lagoas naturais rasas no Cerrado
Autor(es):	Sousa, Rafaella Silveira
Orientador(es):	Bustamante, Mercedes Maria da Cunha
Assunto:	Lagoas naturais - biodiversidade Microbiologia Diversidade microbiana Atividade microbiana
Data de publicação:	26-Abr-2016
Data de defesa:	21-Mar-2016
Referência:	SOUSA, Rafaella Silveira. Caracterização sazonal de comunidades de Bacteria e Archaea em sedimentos de lagoas naturais rasas no Cerrado. 2016. 113 f., il. Dissertação (Mestrado em Biologia Microbiana)—Universidade de Brasília, Brasília, 2016.
Abstract:	Natural shallow and oligotrophic lakes of Cerrado harbor high biodiversity. However, there are no studies about the microbial communities present in the sediment of these aquatic environments. The objective of this work was to characterize the diversity of the Bacteria and Archaea domains in the sediment of two natural lakes of Cerrado (Lagoa Bonita located in Estação de Águas Emendadas – Planaltina/DF and Lagoa Cabocla located in Campo de Instrução de Formosa – Formosa/GO). Water and sediment (0-5 cm) samples were collected from different seasons (transition rainy-dry, dry, transition dry-rainy and rainy season) between May 2014 and March 2015. Physical and chemical characteristics of water and sediment samples were evaluated. Bacterial communities profile was analyzed using PCR/DGGE and the richness and diversity of Bacteria and Archaea domains by pyrosequencing of the 16S rRNA gene. The water in the both lakes showed lightly acidic pH, low electrical conductivity, dissolved oxygen concentrations less than 7.19 mg/L and temperature between 21 and 28ºC. The sediment showed acid pH, high organic matter content, low base saturation and high potential acidity. The analysis of the structure of the evaluated bacterial community (Dice/UPGMA) from profiles of DGGE gels showed high similarity between the communities of the two lakes with greater differentiation in relation to the seasons. From the sequence analyses of 16S rRNA gene, were identified a total of 45 phyla and a group of bacteria not classified in the lower taxonomic hierarchy. Six phyla (Proteobacteria, Acidobacteria, Chloroflexi, Firmicutes, Planctomycetes and Nitrospirae) were considered abundant, with frequency ≥ 1% in all seasons, in the two lakes. Nine abundant phyla (Actinobacteria, Bacteroidetes, OP8, Chlamydiae, Chlorobi, Spirochaetae, TM6, Verrucomicrobia and WD272) and the bacterial group not classified (Unclassified Bacteria) were found in the two lakes at least in one season. We observed the presence of four single bacterial phyla (Caldiserica, KB1, e WS6 and Synergistetes) in lower abundance in the Lagoa Bonita, while in Lagoa Cabocla only one single bacterial phyla (BHI80-139) was recovered. Regarding the groups belonging to the Archaea domain, were identified three phyla (Crenarchaeota, Euryarchaeota and Thaumarchaeota) and two archaeal groups not classified (uncultured archaeon and Unclassified Archaea). Only Euryarchaeota and Thaumarchaeota were considered abundant in the two lakes and in different periods. Relationship of the Bacteria and Archaea phyla were evaluated in combination with water variables (temperature, pH, electrical conductivity, dissolved oxygen and depth of water column) as well as carbon and total nitrogen in the sediment, besides the C:N ratio. The water pH, the electrical conductivity and the depth were the variables of greater relative importance on the abundance of most phyla tested. The bacterial richness was greater in the Lagoa Cabocla, while the archaeal richness and diversity were greater in the Lagoa Bonita. In the two lakes, the seasonality influenced the archaeal richness and had effect on the diversity of Bacteria, which was higher in the dry season compared to transition rain-dry period. The presence of aerobic and anaerobic microorganisms found in the sediment of these lakes, may be indicative the occurrence of interactions between sediment and water body generating heterogeneous microsites for the establishment of groups with such a differentiated ecology. The results of this study include a set of basic and novel information about pristine aquatic environments in the Cerrado, contributing to the expansion of knowledge about the diversity and ecology of the organisms that are important components of ecosystem functions. This information can contribute to the evaluation and planning of conservation strategies for aquatic environments in the Cerrado.
Unidade Acadêmica:	Instituto de Ciências Biológicas (IB) Departamento de Biologia Celular (IB CEL)
Informações adicionais:	Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Biologia Microbiana, 2016.
Programa de pós-graduação:	Programa de Pós-Graduação em Biologia Microbiana
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
DOI:	http://dx.doi.org/10.26512/2016.03.D.20011
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