Metagenomics sheds light on the metabolic repertoire of oil-biodegrading microbes of the South Atlantic Ocean. (June 2019) - Appolinario, Luciana R.
Abstract : Abstract Unplanned oil spills during offshore oil production are a serious problem for the industry and the marine environment. Here we assess the biodegradation potential of marine microorganisms from three water depths in the Campos Basin (South Atlantic Ocean): (i) 5 m (surface), (ii) ∼80 m (chlorophyll maximum layer), and (iii) ∼1200 m (near the bottom). After incubating seawater samples with or without crude oil for 52 days, we used metagenomics and classic microbiology techniques to analyze microbial abundance and diversity, and measured physical-chemical parameters to better understand biodegradation processes. We observed increased microbial abundance and concomitant decreases in dissolved oxygen and hydrocarbon concentrations, indicating oil biodegradation in the three water depths treatments within approximately 27 days. An increase in metagenomic sequences of oil-degrading archaea, fungi, and bacteria ( Alcanivorax, Alteromonas, Colwellia, Marinobacter, and Pseudomonas ) accompanied by a significant increase in metagenomic sequences involved in the degradation of aromatic compounds indicate that crude oil promotes the growth of microorganisms with oil degradation potential. The abundance of genes involved in biodegrading benzene, toluene, ethylbenzene, xylene, alkanes, and poly-aromatic hydrocarbons peaked approximately 3 days after oil addition. All 12 novel metagenome-assembled genomes contained genes involved in hydrocarbon degradation, indicating the oil-degrading potential of planktonic microbes in the Campos Basin. Graphical abstract: Image 1 Highlights: Oil biodegradation may vary throughout the ocean water column. Oil degrading microorganisms increase after oil addition to seawater. Gene sequences involved in petroleum degradation increase consequently. 12 novel microbial lineages (MAGs) have the potential of oil biodegradation. Abstract : "Oil biodegradation occurs throughout the ocean water column with similar biodegradation rates occurring in the surface and deep (∼1200 m) oceanic waters."