A5050068067- Mercury impact and mitigation studies
- Microbial Community Ecology and Physiology
- Environmental DNA in Biodiversity Studies
- Heavy Metal Exposure and Toxicity
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Water Treatment and Disinfection
- Radioactive element chemistry and processing
- Chromium effects and bioremediation
- Atmospheric chemistry and aerosols
- Protist diversity and phylogeny
- Epigenetics and DNA Methylation
- Marine animal studies overview
- Analytical chemistry methods development
- Toxic Organic Pollutants Impact
- Air Quality and Health Impacts
- Solar and Space Plasma Dynamics
- Genomics and Phylogenetic Studies
- Heavy metals in environment
- Arsenic contamination and mitigation
- Per- and polyfluoroalkyl substances research
- Geology and Paleoclimatology Research
- Microbial Fuel Cells and Bioremediation
- Isotope Analysis in Ecology
- Ionosphere and magnetosphere dynamics
La Trobe University
2024
Smithsonian Environmental Research Center
2019-2023
National Synchrotron Light Source II
2022
Brookhaven National Laboratory
2022
Australian Government
2022
Department of Agriculture, Water and the Environment
2022
Oak Ridge National Laboratory
2018-2021
The University of Melbourne
2015-2021
Bodeker Scientific (New Zealand)
2015
Abstract Microbes transform aqueous mercury (Hg) into methylmercury (MeHg), a potent neurotoxin that accumulates in terrestrial and marine food webs, with potential impacts on human health. This process requires the gene pair hgcAB, which encodes for proteins actuate Hg methylation, has been well described anoxic environments. However, recent studies report MeHg formation suboxic seawater, although microorganisms involved remain poorly understood. In this study, we conducted large-scale...
Methylmercury (MeHg) is a bioaccumulative toxic contaminant in many ecosystems, but factors governing its production are poorly understood. Recent work has shown that the anaerobic microbial conversion of mercury (Hg) to MeHg requires Hg-methylation genes hgcAB and these can be used as biomarkers PCR-based estimators Hg-methylator abundance. In an effort determine reliable methods for assessing hgcA abundance diversity linking them concentrations, multiple approaches were compared including...
The gene pair hgcAB is essential for microbial mercury methylation. Our understanding of its abundance and diversity in nature rapidly evolving. In this study we developed a new broad-range primer set hgcAB, plus an expanded reference library, used these to characterize Hg-methylating communities from diverse environments. We applied Hg-methylator database assign taxonomy hgcA sequences clone, amplicon, metagenomic datasets. evaluated potential biases introduced design, sequence length,...
Mercury-contaminated sediment and water contain various Hg species, with a small fraction available for microbial conversion to the bioaccumulative neurotoxin monomethylmercury (MeHg). Quantification of this pool is needed prioritize sites risk management. This study compared efficacy diffusive gradient in thin-film (DGT) passive samplers thiol-based selective extraction method glutathione (GSH) conventional filtration (<0.2 μm) as indicators bioavailability. Anaerobic slurry microcosms were...
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,...
We examined the composition and spatial correlation of sulfur mercury pools in peatland soil profiles by measuring speciation 1s X-ray absorption near-edge structure spectrocopy concentrations cold vapor atomic fluorescence spectroscopy. Also investigated were methylation/demethylation rate constants presence hgcAB genes with depth. Methylmercury (MeHg) concentration organic disulfide spatially correlated had a significant positive (p < 0.05). This finding is consistent these species being...
Methylation of tracer and ambient mercury ((200)Hg (202)Hg, respectively) equilibrated with four different natural organic matter (NOM) isolates was investigated in vivo using the Hg-methylating sulfate-reducing bacterium Desulfobulbus propionicus 1pr3. cultures grown fermentatively environmentally representative concentrations dissolved NOM isolates, Hg[II], HS(-) were assayed for absolute methylmercury (MeHg) concentration conversion Hg(II) to MeHg relative total unfiltered Hg(II). Results...
Abstract. Aerosol observations above the Southern Ocean and Antarctic sea ice are scarce. Measurements of aerosols atmospheric composition were made in East pack on board Australian icebreaker Aurora Australis during spring 2012. One particle formation event was observed 32 days observations. This occurred only day to exhibit extended periods global irradiance excess 600 W m−2. Within single air mass influencing measurements, number concentrations particles larger than 3 nm (CN3) reached...
This work reveals a link between microbial mercury methylation and arsenic resistance may hold clues to the evolution of genes ( hgcAB ). Microbes with produce methylmercury, strong neurotoxin that readily accumulates in food web.
Geothermal systems emit substantial amounts of aqueous, gaseous, and methylated mercury, but little is known about microbial influences on mercury speciation. Here, we report results from genome-resolved metagenomics speciation analysis acidic warm springs in the Ngawha Field (<55°C, pH <4.5), Northland Region, Aotearoa New Zealand. Our aim was to identify microorganisms genetically equipped for methylation, demethylation, or Hg(II) reduction volatile Hg(0) these springs. Dissolved total...
The sulfate-reducing, mercury-methylating strain ND132 T was isolated from the brackish anaerobic bottom sediments of Chesapeake Bay, USA. Capable high levels mercury (Hg) methylation, has been widely used as a model to study process and determine genetic basis Hg methylation. Originally called Desulfovibrio desulfuricans on an early partial 16S rRNA sequence, never formally described. Phylogenetic physiological traits place this within genus Pseudodesulfovibrio, in recently reclassified...
The conversion of mercury (Hg) to monomethylmercury (MMHg) is a critical area concern in global Hg cycling. Periphyton biofilms may harbor significant amounts MMHg but little known about the Hg-methylating potential periphyton microbiome. Therefore, we used high-throughput amplicon sequencing 16S rRNA gene, ITS2 region, and methylation gene pair ( hgcAB ) characterize archaea/bacteria, fungi, microorganisms communities grown contaminated watershed East Tennessee (United States). Furthermore,...
The United Nations 2013 Minamata Convention advocates for updated environmental assessments of potential point-source sites mercury contamination, including historic closed or abandoned mines. Puhipuhi mine (Northland), a and site, is located near one the headwaters Wairoa River. In this study, total levels in soils sediments (37.8–1748 µg g−1), methylated waters (69.6–240 ng L−1 0.637–1.95 L−1, respectively), elemental air (0.06–0.5 m−3) were measured to assess probability form release from...
Subsurface microbial communities mediate the transformation and fate of redox sensitive materials including organic matter, metals radionuclides. Few studies have explored how changing geochemical conditions influence composition groundwater over time. We temporally monitored alterations in abiotic forces on community structure using 1L in-field bioreactors receiving background contaminated at Oak Ridge Reservation, TN. Planktonic biofilm were initialized with water for 4 days to establish...
Abstract The gene pair hgcAB is essential for microbial mercury methylation. Our understanding of its abundance and diversity in nature rapidly evolving. In this study we developed a new broad-range primer set , plus an expanded reference library, used these to characterize Hg-methylating communities from diverse environments. We applied Hg-methylator database assign taxonomy hgcA sequences clone, amplicon, metagenomic datasets. evaluated potential biases introduced design, sequence length,...
Abstract Microbes transform aqueous mercury (Hg) into methylmercury (MeHg), a potent neurotoxin in terrestrial and marine food webs. This process requires the gene pair hgcAB , which encodes for proteins that actuate Hg methylation, has been well described anoxic environments. However, recent studies report potential MeHg formation suboxic seawater, although microorganisms involved remain poorly understood. In this study, we conducted large-scale multi-omic analyses to search putative...
Abstract Mercury 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-MATE (Hg-cycling Microorganisms in Aquatic Terrestrial Ecosystems)...
We sequenced two metagenomes of sediments from the East Fork Poplar Creek in Oak Ridge Reservation (Oak Ridge, TN), a natural stream that has been contaminated with Hg upstream sources, and we reconstructed 28 metagenome-assembled genomes novel prokaryotic species.
Abstract. Aerosol observations above the Southern Ocean and Antarctic sea ice are scarce. Measurements of aerosols atmospheric composition were made in East pack on-board Australian icebreaker Aurora Australis during spring 2012. One particle formation event was observed 32 days observations. This occurred on only day to exhibit extended periods global irradiance excess 600 W m−2. Within single air-mass influencing measurements, number concentrations particles larger than 3 nm (CN3) reached...
Gaseous elemental mercury observations were conducted at Churchill, Victoria, in Australia from April to July, 2013, using a Tekran 2537 analyzer. A strong diurnal variation with daytime average values of 1.2–1.3 ng m–3 and nighttime 1.6–1.8 was observed. These are significantly higher than the Southern Hemisphere 0.85–1.05 m–3. Churchill is Latrobe Valley, approximately 150 km East Melbourne, where 80% Victoria’s electricity generated low-rank brown coal four major power stations: Loy Yang...
ABSTRACT The hgcAB gene pair encodes mercury (Hg) methylation capability in a diverse group of microorganisms, but its evolution and transcriptional regulation remain unknown. Working from the possibility that evolutionary function HgcAB may not be Hg methylation, we test possible link to arsenic resistance. Using model Hg-methylator Pseudodesulfovibrio mercurii ND132, specifically evaluated control by putative ArsR encoded upstream co-transcribed with . This regulator shares homology...