Arsenic in Lake Geneva (Switzerland, France): long term monitoring, and redox and methylation speciation in an As unpolluted, oligo-mesotrophic lake

Filella, Montserrat; Wey, Sebastien; Matoušek, Tomáš; Coster, Mathieu; Rodríguez-Murillo, Juan Carlos; Loizeau, Jean‐Luc

doi:10.1039/d2em00431c

Cited by 6 publications

(4 citation statements)

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“…8A). In particular, DMA(V) is commonly described as an efflux product for microalgae in aquatic environments (Filella et al, 2023;Wang et al, 2015). The corresponding As molecules that could be expelled based on our dataset all have XANES peaks that could contribute o the signature obtained for the As-rich layer of the pool 1 sample (Fig.…”

Section: Arsenic Cycling: No Arsenotrophy But Common Arsenate Detoxif...mentioning

confidence: 83%

Combined genomic and imaging techniques show intense arsenic enrichment caused by detoxification in a microbial mat of the Dead Sea shore

Thomas,

Filella,

Ionescu

et al. 2024

Preprint

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Microbial mats and microbialites are essential tools for reconstructing early life and its environments. To better understand microbial trace element cycling, a microbial mat was collected from the sinkhole systems of the western shores of the Dead Sea, a dynamic environment exhibiting diverse extreme environments. Intense arsenic enrichment (up to 6.5 million times higher than current water concentrations, and 400 times the bulk concentration in the mat) was measured. Arsenic was dominantly found as As(V) in organic molecules, as shown by XANES spectra and high-resolution elemental mapping. Arsenic cycling genes obtained from metagenomic analysis were associated with arsenic detoxification, supporting an active mechanism of As(V) uptake, As(III) efflux and organo-arsenic accumulation in microbial mat extracellular polymeric substances. Thus, we propose that such localized enrichment of As can be attributed to a transient increase in As(V) concentrations in the circulating subsurface water of the Dead Sea shore and its subsequent incorporation in organoarsenic molecules through microbial detoxification processes. Our dataset supports the possibility of metalloid enrichments recorded in very localized facies due to rapid geogenic fluctuations in chemistry of the water flowing over a biofilm. In this context, this example calls for caution when interpreting metal(loid) enrichment in organic matter-rich layers and microbialites of Paleoproterozoic origins. Arsenic signatures in Precambrian organic matter and carbonate rocks may host biosignatures, including evidence of extracellular polymeric susbtances, As-binding and detoxification processes, without supporting arsenotrophy. They do, however, provide clues to better assess paleoenvironmental conditions at the time of microbial mat formation and sedimentation.

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Section: Arsenic Cycling: No Arsenotrophy But Common Arsenate Detoxif...mentioning

confidence: 83%

Combined genomic and imaging techniques show intense arsenic enrichment caused by detoxification in a microbial mat of the Dead Sea shore

Thomas,

Filella,

Ionescu

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…Therefore, we describe a community potential for As detoxification through arsenate reduction into arsenite and efflux out of the cell, either as arsenite or as As(V) methylated compounds (Figure 8a). In particular, DMA(V) is commonly described as an efflux product for microalgae in aquatic environments (Filella et al., 2023; Wang et al., 2015). The corresponding As molecules that could be expelled based on our data set all have XANES peaks that could contribute together to the signature obtained for the As‐rich layer of the pool 1 sample (Figure 8b).…”

Section: Discussionmentioning

confidence: 99%

Combined Genomic and Imaging Techniques Show Intense Arsenic Enrichment Caused by Detoxification in a Microbial Mat of the Dead Sea Shore

Thomas,

Filella,

Ionescu

et al. 2024

Geochem Geophys Geosyst

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Microbial mats and microbialites are essential tools for reconstructing early life and its environments. To better understand microbial trace element cycling, a microbial mat was collected from the sinkhole systems of the western shores of the Dead Sea, a dynamic environment exhibiting diverse extreme environments. Intense arsenic enrichment was measured (up to 6.5 million times higher than current concentrations in water, and 400 times the bulk concentration in the mat). Arsenic was found predominantly as As(V) in organic molecules, as shown by XANES spectra and high‐resolution elemental mapping. Arsenic cycling genes obtained from metagenomic analysis were associated with arsenic detoxification, supporting an active mechanism of As(V) uptake, As(III) efflux and organoarsenic accumulation in the extracellular polymeric substances (EPS) of the mat. Thus, we propose that such localized As enrichment can be attributed to a transient increase in As(V) concentrations in the circulating subsurface water of the Dead Sea shore and its subsequent incorporation into organoarsenic molecules through microbial detoxification processes. Our data set supports the possibility of metalloid enrichment recorded in very localized facies due to rapid geogenic fluctuations in the chemistry of the water flowing over a biofilm. In this context, this example calls for caution in interpreting metal(loid) enrichment in organic matter‐rich layers and microbialites of Paleoproterozoic origin. Arsenic signatures in Precambrian organic matter and carbonate rocks may host biosignatures, including evidence for extracellular polymeric substances, As‐binding and detoxification processes, without supporting arsenotrophy. However, they provide clues to better assess the paleoenvironmental conditions at the time of microbial mat formation.

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“…Thus, this lake offers excellent conditions to study As behaviour in an unpolluted, oxic freshwater body. Filella et al 48 have undertaken long term monitoring and redox and methylation speciation studies to understand the As behaviour in the lake. The ‘dissolved’ As species: As III , total iAs, MMA III , MA (III+V) , DMA (III+V) , and TMAO were analysed by HG-CT-ICP-MS-MS. Water column measurements were also complemented with occasional sampling in the main rivers feeding into the lake and in the interstitial waters of a sediment core.…”

Section: Elemental Speciation Analysismentioning

confidence: 99%

Atomic spectrometry update: review of advances in elemental speciation

Clough,

Harrington,

Hill

et al. 2024

J. Anal. At. Spectrom.

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Arsenic in Lake Geneva (Switzerland, France): long term monitoring, and redox and methylation speciation in an As unpolluted, oligo-mesotrophic lake

Abstract: Arsenic speciation was followed monthly along the spring productivity period (January-June 2021) in the Petit Lac (76 m deep) and in April and June 2021 in the Grand Lac (309.7...

Cited by 6 publications

References 64 publications

Combined genomic and imaging techniques show intense arsenic enrichment caused by detoxification in a microbial mat of the Dead Sea shore

Combined genomic and imaging techniques show intense arsenic enrichment caused by detoxification in a microbial mat of the Dead Sea shore

Combined Genomic and Imaging Techniques Show Intense Arsenic Enrichment Caused by Detoxification in a Microbial Mat of the Dead Sea Shore

Atomic spectrometry update: review of advances in elemental speciation

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