Metagenomic Profiling and Microbial Metabolic Potential of Perdido Fold Belt (NW) and Campeche Knolls (SE) in the Gulf of Mexico

Enrique Merino,Lorenzo Segovia,Alejandro Sanchez-Flores,Adrian Martínez-Santana,Luciana Raggi,Katy Juarez,Alejandra Escobar-Zepeda,Liliana Pardo-Lopez,Rosa María Gutierrez-Rios,Antonio Loza,E Ernestina Godoy-Lozano,Alexei Licea-Navarro,Fernando García-Guevara

doi:10.3389/fmicb.2020.01825

Abstract

The Gulf of Mexico (GoM) is a particular environment that is continuously exposed to hydrocarbon compounds that may influence the microbial community composition. We carried out a metagenomic assessment of the bacterial community to get an overall view of this geographical zone. We analyzed both taxonomic and metabolic markers profiles to explain how the indigenous GoM microorganims participate in the biogeochemical cycling. Two geographically distant regions in the GoM, one in the north-west (NW) and one in the south-east (SE) of the GoM were analyzed and showed differences in their microbial composition and metabolic potential. These differences provide evidence the delicate equilibrium that sustains microbial communities and biogeochemical cycles. Based on the taxonomy and gene groups, the NW are more oxic sediments than SE ones, which have anaerobic conditions. Both water and sediments show the expected sulfur, nitrogen, and hydrocarbon metabolism genes, with particularly high diversity of the hydrocarbon-degrading ones. Accordingly, many of the assigned genera were associated with hydrocarbon degradation processes, Nitrospira and Sva0081 were the most abundant in sediments, while Vibrio, Alteromonas, and Alcanivorax were mostly detected in water samples. This basal-state analysis presents the GoM as a potential source of aerobic and anaerobic hydrocarbon degradation genes important for the ecological dynamics of hydrocarbons and the potential use for water and sediment bioremediation processes.

Highlights

The Gulf of Mexico (GoM) is a basin with one of the most significant oil reservoirs in the world
We found sat and aprA homologous sequences in all sediment samples with some differences in the number of associated homologs and the taxonomy between samples; E03 and A04 metagenomes are similar, both having a high proportion of sequences associated to Alphaproteobacteria and almost no sequences belonging to Deltaproteobacteria in contrast to D18 where there is a high amount of Deltaproteobacteria and no Alphaproteobacteriaassociated genes (Supplementary Figure S1)
In the A04 and E03 samples, we found some homologous sequences to the fmd, ftr and mch genes related to candidate NC10 division bacteria and better related to the Wood–Ljungdahl pathway (WLP)

Summary

Introduction

The Gulf of Mexico (GoM) is a basin with one of the most significant oil reservoirs in the world. There are few microbial diversity studies in Mexican waters of the GoM (LizarrágaPartida, 1986; Rosano-Hernández et al, 2012; Sanchez-Soto et al, 2018; Ramírez et al, 2020) in contrast to an extensive effort along the northeastern coast, related to the Deep Water Horizon oil spill (Kostka et al, 2011; Liu et al, 2012; Mason et al, 2014). The analysis or simulation of functional traits linked directly to microbial richness has seldom been done. One of the first efforts to integrate richness and function is shown in Delmont et al (2018); where the importance of Planctomycetes within the essential nitrogen-fixing microbial population through both a phylogenetic and a functional network analysis was demonstrated

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Results

Discussion

Conclusion