| Congresso Brasileiro de Microbiologia 2023 | Resumo: 608-1 | ||||
Resumo:Inland Petroleum Distribution Systems are designated to provide efficient transportation, storage and distribution of crude and refined oil through extensive areas far from the coast. In this sense, it cannot be ignored that periodic oil spills from pipelines do occur in inland environments, including those surrounding freshwater systems, where many of these facilities are located. Yet, to date, only a small number of studies have considered the impacts of oil spills in riverine systems, despite the clear importance of this environmental risk. In the environment, some microorganisms can metabolize crude oil as a source of carbon and energy and break them down to simpler non-toxic compounds such as CO2 and H2O, in a process called demineralization, but these compounds are overall toxic to the microbiota as well. Considering the importance of microorganisms in biogeochemical cycles in freshwater ecosystems and the constant threat of pollution, it is important to know the extent of the disruptions caused by oil spills. In this research we investigate the effects of crude oil introduction on prokaryotic populations present in the sediment of a freshwater system located inside a protected area at the Brazilian Atlantic Forest, without any known previous exposure to such pollutants. To examine changes in prokaryotic community structures we maintained treated and non-treated microcosms with river water and sediment (Figure 1) over a seven-days exposure period. We performed DNA extraction and 16S rRNA amplicon sequencing for genomic analysis before and after the experiment for each microcosm. For both treatment and controls, 3 microcosms containing river sediments and water were prepared, each (Figure 1). Then, 2 mL of crude oil was added to each microcosm to the concentration of 1% v/v of sediment. The total genomic DNA from all the microcosms was extracted and amplified to specifically target the V4 region of the bacterial 16S rRNA using the primer pair 515F-Y and 806R-XT. DNA sequencing was performed using Illumina MiSeq platform, V2 kit (300 cycles). Data analysis and visualization were performed using the pipeline QIIME2 and R packages. We found that biodiversity decreased in the control microcosms after 7 days, suggesting a rapid depletion of nutrients and the importance of environmental factors that could not be tested in the laboratory. Some taxa in the sediments resisted the oil contamination, while going extinct at the control microcosms, indicating a metabolic potential to use the crude oil as substrate. This indicates that some indigenous prokaryotes in these source sediments could be further studied for oil bioremediation. Importantly, there was intrinsic variance in populations in replicates of all samples, most notably a replicate of the Oil sample where Corynebacteriaceae became the dominant taxa. This represents competing experimental shifts of prokaryotic populations exposed to pollution and suggests that additional replicates may have given rise to alternative evolutions. More research should also be carried out in order to observe the effects of longer term exposure and compare it between the other compartments of the river basin, given its importance as a preservation area.
Keywords: Freshwater microbiome; Crude oil contamination; Microcosms; Environmental impact
Development Agency: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES. Palavras-chave: Freshwater microbiome, Crude oil contamination, Microcosms, Environmental impact Agência de fomento:Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – CAPES | |||||