Graduation Semester and Year




Document Type


Degree Name

Master of Science in Earth and Environmental Science


Earth and Environmental Sciences

First Advisor

Jorge Rodrigues


The Amazon rainforest is known for having a very high diversity of plants and animals. However, it is one of the least understood ecosystems regarding microbial diversity. Microorganisms are important for the ecological balance of any ecosystem and play important role in various biogeochemical cycles. As the Amazon rainforest undergoes to rapid deforestation, loss of its biodiversity is expected. This research aims to determine the effects of deforestation on the soil microbial diversity of the Amazon forest. Toward this, we selected the phylum Verrucomicrobia as a model for observing changes in the microbial structure of rainforest soils. Samples were collected from a research site in the Eastern Amazon basin, Fazenda Nova Vida, State of Rondonia, Brazil. Three different treatments were considered during sampling: a primary forest, a 25 year old pasture, and a secondary forest that was developed after the pasture has been abandoned. Total soil DNA was extracted and used for amplification of the gene 16S rRNA through PCR with specific primers targeting Verrucomicrobia. PCR amplicons were cloned and transformation was carried out into Escherichia coli. After screening, positive clones were sequenced and analysis of the 16S rRNA gene was performed. A total of 750 sequences have been analyzed both at taxonomic and phylogenetic levels. Contrary to our predictions, alpha diversity was higher for pasture and secondary forest, indicating that land use did not decrease local species richness. However, deforestation changed the diversity and distribution of verrucomicrobial population.


Earth Sciences | Physical Sciences and Mathematics


Degree granted by The University of Texas at Arlington