Análise espacial e temporal das comunidades microbianas do sedimento de leito do Rio São Francisco na região da Serra da Canastra em Minas Gerais.

A hydrographic basin is formed through the unevenness of the terrain and through which the rainwater flows between them until the main watercourse, or infiltrates forming water tables and springs. Natural ecosystems and human activities depend on the environmental services that are provided by the river basin. However, rivers suffer from several anthropic impacts, which bring physical-chemical changes in the waters, which reflects in the use and occupation of the land. The São Francisco Hydrographic Basin has 639,219 km² of drainage area that has multiple uses of its waters for the most diverse activities, in addition to receiving great anthropic impact. The main sources of pollution on the São Francisco River are the food industry, limestone extraction, agriculture, livestock, domestic sewage and evidence of deforestation of riparian forests. The UPGRH, which is called the Upper São Francisco Hydrographic Basin (SF1), suffers from several types of anthropogenic pressures that directly impact on the environmental quality of aquatic ecosystems. SF1 is of the greatest importance for monitoring environmental quality, as it covers springs and their first tributaries whose periodic monitoring is done with traditional methods. In this study, microbial communities from the riverbed sediment were used to determine the environmental quality in SF1 under three different types of anthropic impacts: (1) ecotourism activities, (2) urban occupation and (3) agricultural activities with the source as a control. Therefore, the microbial communities of the sediment of the day bed suffer from these anthropic actions and activities and have their structures modified, thus being able to be used in environmental quality studies. In the first article (chapter 1), the use of taxonomic and functional structure of microbial communities is addressed to determine the influence of land uses in their community and functionality, where microbial groups, candidates for bioindicators, organisms that due to their sensitivity, may indicate changes in the environment due to their presence or absence. Microbial communities of river bed sediment reflect land use in their composition and can be excellent bioindicators In the second article (chapter 2), the influence of land use on microbial sediment communities is evaluated in a temporal and spatial way. of the São Francisco riverbed and, in chapter 3, it was shown how the results can be used in a new methodology of water analysis using the structure of the communities as a source of data for anthropic impacts on water bodies..