Ecosystem Controls on Methylmercury Production by Periphyton Biofilms in a Contaminated Stream: Implications for Predictive Modeling

Schwartz, Grace; Olsen, Todd A.; Muller, Katherine A.; Brooks, Scott C.

doi:10.1002/etc.4551

Cited by 17 publications

(18 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recent studies suggested a transient availability rate potentials calculation, a modification of the original Hg methylation kinetic model from H. Hintelmann et al ( 43 ) through the determination and addition of sorption reaction kinetics, leading to k m 15 times higher than the full availability rate potentials ( 29 , 44 ). However, the remoteness of our sites and field laboratory has prevented the determination of such additional sorption constants to fit the equations.…”

Section: Resultsmentioning

confidence: 99%

“…The hgcAB genes were detected in periphyton from a high-altitude tropical lake ( 5 ) and subtropical wetlands of the Florida Everglades ( 26 ) with a predominance of sulfate reducers, methanogens, and syntrophs as putative Hg methylators. In addition to the genetic evidence of diverse methylator communities in periphyton, studies using isotopic approaches to estimate Hg transformation kinetics have shown that temperature, depth, light exposure, extracellular ligand concentrations, and biofilm structure are all factors influencing Hg methylation rates in periphyton ( 5 , 6 , 27 – 29 ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microbial Diversity and Mercury Methylation Activity in Periphytic Biofilms at a Run-of-River Hydroelectric Dam and Constructed Wetlands

Leclerc

Harrison

Storck

et al. 2021

mSphere

View full text Add to dashboard Cite

Periphytic biofilms have the potential to greatly influence the microbial production of the neurotoxicant monomethylmercury in freshwaters although few studies have simultaneously assessed periphyton mercury methylation and demethylation rates and the microbial communities associated with these transformations. We performed a field study on periphyton from a river affected by run-of-river power plants and artificial wetlands in a boreal landscape (Québec, Canada). In situ incubations were performed on three sites using environmental concentrations of isotopically enriched monomethylmercury (MM198Hg) and inorganic mercury (200Hg) for demethylation and methylation rate measurements. Periphytic microbial communities were investigated through 16S rRNA gene analyses and metagenomic screenings for the hgcA gene, involved in mercury methylation. Positive mercury methylation rates ([5.9 ± 3.4] × 10−3 day−1) were observed only in the wetlands, and demethylation rates averaged 1.78 ± 0.21 day−1 for the three studied sites. The 16S rRNA gene analyses revealed Proteobacteria as the most abundant phylum across all sites (36.3% ± 1.4%), from which families associated with mercury methylation were mostly found in the wetland site. Metagenome screening for HgcA identified 24 different hgcA sequences in the constructed wetland site only, associated with 8 known families, where the iron-reducing Geobacteraceae were the most abundant. This work brings new information on mercury methylation in periphyton from habitats of impacted rivers, associating it mostly with putative iron-reducing bacteria. IMPORTANCE Monomethylmercury (MMHg) is a biomagnifiable neurotoxin of global concern with risks to human health mostly associated with fish consumption. Hydroelectric reservoirs are known to be sources of MMHg many years after their impoundment. Little is known, however, on run-of-river dams flooding smaller terrestrial areas, although their numbers are expected to increase considerably worldwide in decades to come. Production of MMHg is associated mostly with anaerobic processes, but Hg methylation has been shown to occur in periphytic biofilms located in oxic zones of the water column. Therefore, in this study, we investigated in situ production of MMHg by periphytic communities in habitats impacted by the construction of a run-of-river dam by combining transformation rate measurements with genomic approaches targeting hgcAB genes, responsible for mercury methylation. These results provide extended knowledge on mercury methylators in river ecosystems impacted by run-of-river dams in temperate habitats.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microbial Diversity and Mercury Methylation Activity in Periphytic Biofilms at a Run-of-River Hydroelectric Dam and Constructed Wetlands

Leclerc

Harrison

Storck

et al. 2021

mSphere

View full text Add to dashboard Cite

show abstract

“…To further explore the role of periphyton biofilms in Hg cycling, biofilms were grown in the creek, returned to the lab, and amended with enriched stable isotopes of inorganic 201 Hg and Me 202 Hg (Olsen et al 2016, Schwartz et al 2019. The production of isotopically labeled Me 201 Hg and loss of Me 202 Hg was monitored over time as measures of Hg methylation and MeHg demethylation, respectively (figure 11).…”

Section: Field-informed Laboratory Experiments Identify a Dominant So...mentioning

confidence: 99%

From legacy contamination to watershed systems science: a review of scientific insights and technologies developed through DOE-supported research in water and energy security

Dwivedi

Steefel

Arora

et al. 2022

Environ. Res. Lett.

View full text Add to dashboard Cite

Water resources, including groundwater and prominent rivers worldwide, are under duress because of excessive contaminant and nutrient loads. To help mitigate this problem, the United States Department of Energy (DOE) has supported research since the late 1980s to improve our fundamental knowledge of processes that could be used to help clean up challenging subsurface problems. Problems of interest have included subsurface radioactive waste, heavy metals, and metalloids (e.g., uranium, mercury, arsenic). Research efforts have provided insights into detailed groundwater biogeochemical process coupling and the resulting geochemical exports of metals and nutrients to surrounding environments. Recently, an increased focus has been placed on constraining the exchanges and fates of carbon and nitrogen within and across bedrock to canopy compartments of a watershed and in river-floodplain settings, because of their important role in driving biogeochemical interactions with contaminants and the potential of increased fluxes under changing precipitation regimes, including extreme events. While reviewing the extensive research that has been conducted at DOE's representative sites and testbeds (such as the Oyster Site in Virginia, Savannah River Site in South Carolina, Oak Ridge Reservation in Tennessee, Hanford in Washington, Nevada National Security in Nevada, Riverton in Wyoming, and Rifle and East River in Colorado), this review paper explores the nature and distribution of contaminants in the surface and shallow subsurface (i.e., the critical zone) and their interactions with carbon and nitrogen dynamics. We also describe state-of-the-art, scale-aware characterization approaches and models developed to predict contaminant fate and transport. The models take advantage of DOE leadership-class high-performance computers and are beginning to incorporate artificial intelligence approaches to tackle the extreme diversity of hydro-biogeochemical processes and measurements. Recognizing that the insights and capability developments are potentially transferable to many other sites, we also explore the scientific implications of these advances and recommend future research directions.

show abstract

“…WEOC was measured on a total organic carbon analyzer (TOC, Shimadzu) after the samples were acidified in 0.1% HCl and purged to remove inorganic carbonates (Philben et al, 2019;Yang et al, 2016b), and the detection limit was ~0.31 µmol C g -1 dw. For statistical analyses, all data were validated for normality using Shapiro-Wilk test (Schwartz et al, 2019). Differences in Hg species distributions between the two soils were tested by the two-sample t-test.…”

Section: Chemicals and Chemical Analysesmentioning

confidence: 99%

Unravelling biogeochemical drivers of methylmercury production in an Arctic fen soil and a bog soil

Zhang

Philben

Taş

et al. 2022

Environmental Pollution

View full text Add to dashboard Cite

Ecosystem Controls on Methylmercury Production by Periphyton Biofilms in a Contaminated Stream: Implications for Predictive Modeling

Cited by 17 publications

References 45 publications

Microbial Diversity and Mercury Methylation Activity in Periphytic Biofilms at a Run-of-River Hydroelectric Dam and Constructed Wetlands

Microbial Diversity and Mercury Methylation Activity in Periphytic Biofilms at a Run-of-River Hydroelectric Dam and Constructed Wetlands

From legacy contamination to watershed systems science: a review of scientific insights and technologies developed through DOE-supported research in water and energy security

Unravelling biogeochemical drivers of methylmercury production in an Arctic fen soil and a bog soil

Contact Info

Product

Resources

About