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Deltaproteobacteria and Spirochaetes-Like Bacteria Are Abundant Putative Mercury Methylators in Oxygen-Deficient Water and Marine Particles in the Baltic Sea
- Source :
- Frontiers in Microbiology, Vol 11 (2020), Digital.CSIC. Repositorio Institucional del CSIC, instname, Frontiers in Microbiology
- Publication Year :
- 2020
- Publisher :
- Frontiers Media S.A., 2020.
-
Abstract
- New Insights into the Microbial and Chemical Processes Controlling Mercury Biogeochemical Cycling.-- 11 pages, 4 figures, 2 tables, supplementary material https://www.frontiersin.org/articles/10.3389/fmicb.2020.574080/full#supplementary-material<br />Methylmercury (MeHg), a neurotoxic compound biomagnifying in aquatic food webs, can be a threat to human health via fish consumption. However, the composition and distribution of the microbial communities mediating the methylation of mercury (Hg) to MeHg in marine systems remain largely unknown. In order to fill this knowledge gap, we used the Baltic Sea Reference Metagenome (BARM) dataset to study the abundance and distribution of the genes involved in Hg methylation (the hgcAB gene cluster). We determined the relative abundance of the hgcAB genes and their taxonomic identity in 81 brackish metagenomes that cover spatial, seasonal and redox variability in the Baltic Sea water column. The hgcAB genes were predominantly detected in anoxic water, but some hgcAB genes were also detected in hypoxic and normoxic waters. Phylogenetic analysis identified putative Hg methylators within Deltaproteobacteria, in oxygen-deficient water layers, but also Spirochaetes-like and Kiritimatiellaeota-like bacteria. Higher relative quantities of hgcAB genes were found in metagenomes from marine particles compared to free-living communities in anoxic water, suggesting that such particles are hotspot habitats for Hg methylators in oxygen-depleted seawater. Altogether, our work unveils the diversity of the microorganisms with the potential to mediate MeHg production in the Baltic Sea and pinpoint the important ecological niches for these microorganisms within the marine water column<br />AB acknowledges the Marie Curie Individual Fellowship (H2020-MSCA-IF-2016; project-749645)<br />With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)
- Subjects :
- Microbiology (medical)
Deltaproteobacteria
Baltic Sea
Microorganism
lcsh:QR1-502
spirochaetes-like bacteria
Mercury methylation
Microbiology
lcsh:Microbiology
03 medical and health sciences
chemistry.chemical_compound
Water column
deltaproteobacteria
14. Life underwater
Methylmercury
Relative species abundance
Original Research
030304 developmental biology
0303 health sciences
Brackish water
biology
030306 microbiology
Ecology
hgcAB
biology.organism_classification
Anoxic waters
Mikrobiologi
Microbiology (Microbiology in the medical area to be 30109)
chemistry
Spirochaetes-like bacteria
13. Climate action
mercury methylation
Seawater
Subjects
Details
- Language :
- English
- Volume :
- 11
- Database :
- OpenAIRE
- Journal :
- Frontiers in Microbiology
- Accession number :
- edsair.doi.dedup.....63237560d72d3806ea38ed4a5bd2bf84