Global change effects on biogeochemical mercury cycling

AMBIO, Год журнала: 2023, Номер 52(5), С. 853 - 876

Опубликована: Март 29, 2023

Abstract Past and present anthropogenic mercury (Hg) release to ecosystems causes neurotoxicity cardiovascular disease in humans with an estimated economic cost of $117 billion USD annually. Humans are primarily exposed Hg via the consumption contaminated freshwater marine fish. The UNEP Minamata Convention on aims curb environment is accompanied by global monitoring efforts track its success. biogeochemical cycle a complex cascade release, dispersal, transformation bio-uptake processes that link sources exposure. Global change interacts impacting physical, ecological factors control these processes. In this review we examine how such as biome shifts, deforestation, permafrost thaw or ocean stratification will alter cycling Based past declines environmental levels, expect future policy impacts should be distinguishable from effects at regional scales.

Язык: Английский

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Environmental formation of methylmercury is controlled by synergy of inorganic mercury bioavailability and microbial mercury‐methylation capacity

Environmental Microbiology, Год журнала: 2023, Номер 25(8), С. 1409 - 1423

Опубликована: Март 5, 2023

Abstract Methylmercury (MeHg) production is controlled by the bioavailability of inorganic divalent mercury (Hg(II) i ) and Hg‐methylation capacity microbial community (conferred hgcAB gene cluster). However, relative importance these factors their interaction in environment remain poorly understood. Here, metagenomic sequencing a full‐factorial MeHg formation experiment were conducted across wetland sulfate gradient with different communities pore water chemistries. From this experiment, each factor on was isolated. Hg(II) correlated dissolved organic matter composition, while abundance hgcA genes. responded synergistically to both factors. Notably, sequences from diverse taxonomic groups, none which contained genes for dissimilatory reduction. This work expands our understanding geochemical constraints situ provides an experimental framework further mechanistic studies.

Язык: Английский

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Recent advance of microbial mercury methylation in the environment

Applied Microbiology and Biotechnology, Год журнала: 2024, Номер 108(1)

Опубликована: Фев. 26, 2024

Abstract Methylmercury formation is mainly driven by microbial-mediated process. The mechanism of microbial mercury methylation has become a crucial research topic for understanding in the environment. Pioneering studies are focusing on functional strain isolation, community composition characterization, and elucidation various environments. Therefore, genes methylation, global isolations Hg strains, their potential were systematically analyzed, methylators typical environments extensively reviewed. main drivers (key physicochemical factors microbiota) summarized discussed. Though significant progress been explored recent decade, it still limited several aspects, including (1) molecular biology techniques identifying methylators; (2) characterization methods potential; (3) complex environmental properties (environmental factors, communities, etc.). Accordingly, strategies studying proposed. These include following: development new to characterize treating environment as micro-ecosystem them from holistic perspective clearly understand methylation; more reasonable sensitive inhibition test needs be considered. Key points • Global phylogenetically functionally compared condition. Future study Graphical

Язык: Английский

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Distribution and Environmental Preference of Potential Mercury Methylators in Paddy Soils across China

Environmental Science & Technology, Год журнала: 2025, Номер unknown

Опубликована: Янв. 17, 2025

The neurotoxin methylmercury (MeHg) is produced mainly from the transformation of inorganic Hg by microorganisms carrying hgcAB gene pair. Paddy soils are known to harbor diverse microbial communities exhibiting varying abilities in methylating Hg, but their distribution and environmental drivers remain unknown at a large spatial scale. Using hgcA amplicon sequencing, this study examined Hg-methylating major rice-producing paddy across transect ∼3600 km an altitude ∼1300 m China. Results showed that hgcA+ OTU richness was higher tropical subtropical compared temperate zones. Geobacteraceae, Smithellaceae, Methanoregulaceae were identified as dominant families associated with MeHg production, collectively accounting for up 77% total sequences. Hierarchical partitioning analyses revealed pH main driver genes Geobacteraceae (14.8%) (16.3%), while accounted 21.4% Smithellaceae. Based on these preferences, machine-learning algorithm used predict families, thereby providing novel insights into important determinants improved prediction production

Язык: Английский

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Sulfate Reduction Drives Elevated Methylmercury Formation in the Water Column of a Eutrophic Freshwater Lake

Environmental Science & Technology, Год журнала: 2025, Номер unknown

Опубликована: Март 28, 2025

Mercury (Hg) contamination of aquatic food webs is controlled in part by the formation and accumulation toxic bioaccumulative methylmercury (MeHg). MeHg production mediated metabolically diverse microorganisms carrying hgcAB gene pair, while demethylation reaction several biotic abiotic processes. However, relative importance these two processes on environmental factors that influence them are poorly characterized, especially eutrophic environments. In this study, both Hg methylation a freshwater lake were linked to ambient concentrations hgcA abundance expression. High rate potentials indicated situ was key source water column, driven high transcription. Molybdate treatment decreased potentials, highlighting sulfate reduction driving formation. Sulfate-reducing bacteria accounted for over 50% transcription, despite representing less than 10% hgcA-carrying microbial community. An arsR-like transcriptional regulator preceded many sequences; transcriptionally active lower Overall, study elucidates biogeochemical understudied

Язык: Английский

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Metabolically diverse microorganisms mediate methylmercury formation under nitrate-reducing conditions in a dynamic hydroelectric reservoir

The ISME Journal, Год журнала: 2023, Номер 17(10), С. 1705 - 1718

Опубликована: Июль 26, 2023

Brownlee Reservoir is a mercury (Hg)-impaired hydroelectric reservoir that exhibits dynamic hydrological and geochemical conditions located within the Hells Canyon Complex in Idaho, USA. Methylmercury (MeHg) contamination fish concern reservoir. While MeHg production has historically been attributed to sulfate-reducing bacteria methanogenic archaea, microorganisms carrying hgcA gene are taxonomically metabolically diverse major biogeochemical cycles driving (Hg) methylation not well understood. In this study, Hg speciation redox-active compounds were measured throughout across stratified period four consecutive years (2016-2019) identify location where redox under which produced. Metagenomic sequencing was performed on subset of samples characterize microbial community with possible links between production. Biogeochemical profiles suggested situ water column source MeHg. These profiles, combined genome-resolved metagenomics focused hgcA-carrying microbes, indicated occurs system nitrate- or manganese-reducing conditions, previously thought preclude Hg-methylation. Using multidisciplinary approach, we identified cascading effects interannual variability hydrology status, metabolic strategies, abundance diversity methylators, ultimately concentrations This work expands known conducive producing suggests Hg-methylation mitigation efforts by nitrate manganese amendment may be unsuccessful some locations.

Язык: Английский

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Dimethylmercury as a Source of Monomethylmercury in a Highly Productive Upwelling System

Environmental Science & Technology, Год журнала: 2024, Номер 58(24), С. 10591 - 10600

Опубликована: Июнь 7, 2024

Monomethylmercury (MMHg) is a neurotoxicant that biomagnifies in marine food webs, reaching high concentrations apex predators. To predict changes oceanic MMHg concentrations, it important to quantify the sources and sinks of MMHg. Here, we study mercury speciation California Current System through cruise sampling modeling. Previous work has found upwelling transports mercury-enriched deep waters productive surface waters. These upwelled originate within Undercurrent water mass are subsequently advected as parcel Current. Between two major masses, find compared Current, contains elevated dissolved total (THg) dimethylmercury (DMHg) by 59 69%, respectively. We explain these differences result from losses during advection, specifically scavenging THg DMHg demethylation. calculate net demethylation rate 2.0 ± 1.1% d

Язык: Английский

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A consensus protocol for the recovery of mercury methylation genes from metagenomes

Molecular Ecology Resources, Год журнала: 2022, Номер 23(1), С. 190 - 204

Опубликована: Июль 15, 2022

Mercury (Hg) methylation genes (hgcAB) mediate the formation of toxic methylmercury and have been identified from diverse environments, including freshwater marine ecosystems, Arctic permafrost, forest paddy soils, coal-ash amended sediments, chlor-alkali plants discharges geothermal springs. Here we present first attempt at a standardized protocol for detection, identification quantification hgc metagenomes. Our Hg-cycling microorganisms in aquatic terrestrial ecosystems (Hg-MATE) database, catalogue genes, provides most accurate information to date on taxonomic identity functional/metabolic attributes responsible Hg environment. Furthermore, introduce "marky-coco", ready-to-use bioinformatic pipeline based de novo single-metagenome assembly, easy characterization environmental samples. We compared recovery metagenomes using marky-coco with an approach coassembly multiple data show similar efficiency both approaches environments except those high diversity (i.e., soils) which was preferred. Finally, discuss definition true methods normalize gene counts

Язык: Английский

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Revisiting the mercury cycle in marine sediments: A potential multifaceted role for Desulfobacterota

Journal of Hazardous Materials, Год журнала: 2023, Номер 465, С. 133120 - 133120

Опубликована: Ноя. 29, 2023

Marine sediments impacted by urban and industrial pollutants are typically exposed to reducing conditions represent major reservoirs of toxic mercury species. Mercury methylation mediated anaerobic microorganisms is favored under such conditions, yet little known about potential microbial mechanisms for detoxification. We used culture-independent (metagenomics, metabarcoding) culture-dependent approaches in anoxic marine identify indicators pollution analyze the distribution genes involved reduction (merA) demethylation (merB). While none isolates featured merB genes, 52 isolates, predominantly affiliated with Gammaproteobacteria, were merA positive. In contrast, detected metagenomes assigned different phyla, including Desulfobacterota, Actinomycetota, Gemmatimonadota, Nitrospirota, Pseudomonadota. This indicates a widespread capacity sediment microbiomes. Notably, predominately identified phylum previously associated only methylation. Marker latter process (hgcAB) also mainly implying central multifaceted role this cycle. Network analysis revealed that Desulfobacterota fermenters, methanogens sulfur-oxidizers, indicating interactions between key players carbon, sulfur cycling sediments.

Язык: Английский

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Interaction of Naturally Occurring Phytoplankton with the Biogeochemical Cycling of Mercury in Aquatic Environments and Its Effects on Global Hg Pollution and Public Health

Microorganisms, Год журнала: 2023, Номер 11(8), С. 2034 - 2034

Опубликована: Авг. 8, 2023

The biogeochemical cycling of mercury in aquatic environments is a complex process driven by various factors, such as ambient temperature, seasonal variations, methylating bacteria activity, dissolved oxygen levels, and Hg interaction with organic matter (DOM). As consequence, part the contamination from anthropogenic activity that was buried sediments reinserted into water columns mainly highly toxic forms (methylmercury, dimethylmercury, etc.). This especially prominent coastal shallow waters industrial regions worldwide. main entrance point these food web naturally occurring phytoplankton. availability, intake, effect on population size, cell toxicity, eventual biotransformation, intracellular stability phytoplankton are greatest importance for human health, having mind incorporated inside cells due to biomagnification effects eventually ends up wildlife, fish, seafood, diet. review summarizes recent findings topic form natural offers new insight possible directions future research prevention scope climate change global pollution increase scenarios.

Язык: Английский

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