DOI: 10.5061/dryad.9zw3r22mz
title: A genome catalogue of mercury-methylating bacteria and archaea from sediments of a boreal river facing human disturbances

description: Methyl mercury is a toxic compound produced by anaerobic microbes that
 biomagnifies in aquatic food webs, impacting animal and human
 health. Genome-based explorations of Hg methylators remain
 limited, particularly in the context of river ecosystems. To fill this
 knowledge gap, we created a genome catalogue of putative
 Hg-methylating microorganisms (based on the presence of hgcAB)
 from the sediments of a river impacted by two run-of-river hydroelectric
 dams, logging, and a wildfire. By using genome-resolved metagenomics, we
 uncovered a unique and diverse assemblage of Hg methylators dominated by
 members of the metabolically versatile Bacteroidota and particularly
 enriched in butyrate fermentative microbes. By comparing diversity and
 abundance of Hg methylators between sites that were subjected to different
 disturbances, we found that ongoing disturbances, such as input of organic
 matter related to logging activities, were particularly favorable to the
 establishment of a Hg-methylating niche. Lastly, for a deeper
 understanding of the environmental factors shaping Hg methylator
 diversity, we juxtaposed the Hg-methylating genome catalogue with the
 wider microbial community. The results suggest that Hg methylators respond
 to environmental conditions similarly to overall microbial community, and
 therefore it is crucial to interpret the diversity and abundance of Hg
 methylators within their specific ecological context.
description: Detailed methods are described in associated publication.
description: # Metagenome-assembled genomes catalogue from sediments of a boreal river
 facing human disturbances 
 The metagenome-assembled genomes (MAGs) included in this catalogue were
 generated from six combined assembly corresponding to the six sampling
 sites from which sediment cores were collected along the St. Maurice
 River. This repository contains contigs, amino acid sequences and genome
 features of the 850 MAGs that comprise this catalogue. ## Contact
 information Address correspondence to David A. Walsh,
 . ## Description of the data and file
 structure The MAGs in this catalogue underwent quality filtering based on
 contamination and completeness, and only high and medium-quality MAGs were
 retained (&lt; 10% contamination and &gt; 50% completeness). They were
 then dereplicated at ≥95% average nucleotide identity (ANI), after which
 only the best species representative were kept. Each compressed folder
 represent different information included in this catalogue, and contain
 one file per MAG : * StMaurice_MAGs_contigs.tar.gz: compressed folder
 containing nucleotide sequence of contigs in each MAG in FASTA format (.fa
 file extension); * StMaurice_MAGs_aa.tar.gz: compressed folder containing
 the annotated amino acid sequence of each MAG in FASTA format (.faa file
 extension); * StMaurice_MAGs_gff.tar.gz: compressed folder containing
 annotated genome features in General Feature format (.gff file extension).
 ## File naming system Files were named after each MAG, which were prefixed
 with the sampling site they were generated from. Please refer to the
 published manuscript for the exact locations of the sampling sites. WEM-4:
 constructed channels REF-2 : reference site CA-10 : site flooded by
 run-of-river dam and close to area affected by wildfire CA-6: site flooded
 by run-of-river dam and close to area affected by wildfire RDC-10 : site
 flooded by run-of-river dam and close to logging activities RDC-14: site
 flooded by run-of-river dam and close to logging activities ##
 Sharing/Access information Links to other publicly accessible locations of
 the data: * Raw metagenomic reads are available at the European Nucleotide
 Archive under study accession [PRJEB67532]
 ( * Combined
 assemblies were deposited and annotated at the Joint Genome Institute
 (JGI) Genomes OnLine Database (GOLD) under study accession [Gs0164199] *
 [\[Ga0619462\] :
 RDC-14](https://gold.jgi.doe.gov/analysis_project?id=Ga0619462) *
 [\[Ga0619461\]:
 RDC-10](https://gold.jgi.doe.gov/analysis_project?id=Ga0619461) *
 [\[Ga0619460\] :
 CA-6](https://gold.jgi.doe.gov/analysis_project?id=Ga0619460) *
 [\[Ga0619459\] :
 CA-10](https://gold.jgi.doe.gov/analysis_project?id=Ga0619459) *
 [\[Ga0619418\] :
 REF-2](https://gold.jgi.doe.gov/analysis_project?id=Ga0619418) *
 [\[Ga0619417\] :
 WEM-4](https://gold.jgi.doe.gov/analysis_project?id=Ga0619417)