The Deep-Sea Microbial Community from the Amazonian Basin Associated with Oil Degradation

Abstract

One consequence of oil production is the possibility of unplanned accidental oil spills; therefore, it is important to evaluate the potential of indigenous microorganisms (both prokaryotes and eukaryotes) from different oceanic basins to degrade oil. The aim of this study was to characterize the microbial response during the biodegradation process of Brazilian crude oil, both with and without the addition of the dispersant Corexit 9500, using deep-sea water samples from the Amazon equatorial margin basins, Foz do Amazonas and Barreirinhas, in the dark and at low temperatures (4°C). We collected deep-sea samples in the field (about 2570 m below the sea surface), transported the samples back to the laboratory under controlled environmental conditions (5°C in the dark) and subsequently performed two laboratory biodegradation experiments that used metagenomics supported by classical microbiological methods and chemical analysis to elucidate both taxonomic and functional microbial diversity. We also analyzed several physical–chemical and biological parameters related to oil biodegradation. The concomitant depletion of dissolved oxygen levels, oil droplet density characteristic to oil biodegradation, and BTEX concentration with an increase in microbial counts revealed that oil can be degraded by the autochthonous deep-sea microbial communities. Indigenous bacteria (e.g., Alteromonadaceae, Colwelliaceae, and Alcanivoracaceae), archaea (e.g., Halobacteriaceae, Desulfurococcaceae, and Methanobacteriaceae), and eukaryotic microbes (e.g., Microsporidia, Ascomycota, and Basidiomycota) from the Amazonian margin deep-sea water were involved in biodegradation of Brazilian crude oil within less than 48-days in both treatments, with and without dispersant, possibly transforming oil into microbial biomass that may fuel the marine food web.

Distribution of Archaeal Communities along the Coast of the Gulf of Finland and Their Response to Oil Contamination

“…The genus Thermococcus is comprised of sulfur-reducing hyperthermophilic archaea that have a good stress response system (Fukui et al, 2005 ). Studies have demonstrated that anaerobic hydrocarbon degradation is associated with sulfate reduction, fermentative growth, and/or methanogenesis in oil-contaminated marine environments, without requiring exogenous electron acceptors (Orcutt et al, 2010 ; Kotlar et al, 2011 ; Lu et al, 2012 ; Campeão et al, 2017 ). Therefore, the observed co-occurrence patterns of these three taxa with high abundance in the pMENs probably implies potential relevant syntrophic connections between in situ hydrocarbon degradation, sulfur reduction, nitrate reduction, and methane production in the littoral sediment.…”

ColwelliaandMarinobactermetapangenomes reveal species-specific responses to oil and dispersant exposure in deepsea microbial communities

“…Seven weeks after the initiation of the oil spill, the dominant Oceanospirillales communities shifted to a community dominated by Cycloclasticus and Colwellia [15][16][17] . Subsequent research showed that some Colwellia responded rapidly in situ 17,18 , and in experiments utilizing controlled additions of oil and dispersed oil 3,17,19 . Other species typically associated with hydrocarbon degradation in the Gulf (i.e., Alcanivorax) were not detected in plume samples 12,15,20,21 .…”

Discovery of functional gene markers of bacteria for monitoring hydrocarbon pollution in the marine environment - a metatranscriptomics approach

“…Colwellia aromaticivorans was reported as a novel hydrocarbon-degrading bacterium identified through metagenomic analysis of a microcosm-scale oil exposure experiment (Campeao, Reis et al 2017, Campeao, Swings et al 2019). However, isolation and confirmation of this strain being able to grow on petroleum hydrocarbons has not been performed, only in silico predictions of its metabolic profile have been reported.…”