Influence of global change-related impacts on the mercury toxicity of freshwater algal communities

Val, Jonatan; Muñiz, Selene; Gomà, Joan; Navarro, Enrique

doi:10.1016/j.scitotenv.2015.05.042

Cited by 20 publications

(11 citation statements)

References 58 publications

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“…However, in the case of Hg, there is a paucity of information concerning the validity of this concept. In agreement with the PICT concept, high Hg tolerance of biofilm collected from the contaminated site of Jabarella, Gallego River (Spain) containing 0.014 ppm Hg in water was recently reported [95]. The community composition was characterized in terms of alga and diatoms, with the filamentous alga Oedognium dominating at the contaminated Jabarella site.…”

supporting

confidence: 72%

Mercury bioavailability, transformations, and effects on freshwater biofilms

Dranguet

Faucheur

2017

Enviro Toxic and Chemistry

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Mercury (Hg) compounds represent an important risk to aquatic ecosystems because of their persistence, bioaccumulation, and biomagnification potential. In the present review, we critically examine state-of-the-art studies on the interactions of Hg compounds with freshwater biofilms, with an emphasis on Hg accumulation, transformations, and effects. Freshwater biofilms contain both primary producers (e.g., algae) and decomposers (e.g., bacteria and fungi), which contribute to both aquatic food webs and the microbial loop. Hence they play a central role in shallow water and streams, and also contribute to Hg trophic transfer through their consumption. Both inorganic and methylated mercury compounds accumulate in biofilms, which could transform them mainly by methylation, demethylation, and reduction. Accumulated Hg compounds could induce diverse metabolic and physiological perturbations in the microorganisms embedded in the biofilm matrix and affect their community composition. The bioavailability of Hg compounds, their transformations, and their effects depend on their concentrations and speciation, ambient water characteristics, biofilm matrix composition, and microorganism-specific characteristics. The basic processes governing the interactions of Hg compounds with biofilm constituents are understudied. The development of novel conceptual and methodological approaches allowing an understanding of the chemo-and biodynamic aspects is necessary to improve the knowledge on Hg cycling in shallow water as well as to enable improved use of freshwater biofilms as potential indicators of water quality and to support better informed risk assessment. Environ Toxicol Chem 2017;36:3194-3205. # 2017 SETAC

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supporting

confidence: 72%

Mercury bioavailability, transformations, and effects on freshwater biofilms

Dranguet

Faucheur

2017

Enviro Toxic and Chemistry

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“…A similar pattern was observed in biofilms collected in reservoirs contaminated by industrial Hg release [19]. Algal species shift was demonstrated in the Gallego River with the higher abundance of the filamentous algae Oedognium and Stigeoclonium in biofilms living at the most contaminated site (~70 pM Hg), suggesting that both species could be tolerant to Hg [17]. In the Olt River (Romania) under the influence of chlor-alkali plant effluents, the dominant species in the biofilm communities were the Cyanobacteria for algae, Bacillariophyta for algae, and Taphrinomycetes for fungi [20].…”

Section: Introductionsupporting

confidence: 71%

“…That phenomenon was accompanied by a decrease of the microalgae cell size whereas a shift from sensitive to more tolerant species was also observed with the decrease of Navicula aquaedurae and with the increase of both Nitzschia palea and Fallacia pygmaea abundance. Three communities of biofilms collected at different sites along the Gallego River (Spain) and exposed to Hg in microcosms for a short period of time (1 h and 2 h) had EC 50 values varying between 0.7 µM and 3.6 µM for the most sensitive population and between 100 µM and 200 µM for the least sensitive [17]. In agreement with these studies, a shift in bacterial and microalgal communities upon Hg exposure were also evidenced in the field.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Effects of Mercury on Biofilms Grown in Contaminated Microcosms: A Pilot Study

2019

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Biofilms are important components of the mercury (Hg) biogeochemical cycle. However, Hg effects on biofilm communities are overlooked. Here, we present results of a pilot study on the chronic effects of Hg on biofilms, notably on the potential change of their taxonomic composition. Biofilms were cultivated in microcosms enriched with three different Hg concentrations (11 ± 2 pM, 121 ± 9 pM and 1454 ± 54 pM) for 55 days and examined for their accumulated Hg concentrations and composition. Bioaccumulated Hg concentrations were representative of those encountered in natural environments. Despite the lack of influence on the ash free dry weight and chlorophyll content, the surface coverage of the substrata of biofilms grown in Hg decreased. Algal community were strongly affected by Hg, with a decrease in their richness with Ochrophyta found as the most sensitive phyla. The diversity and richness of bacterial communities did not change upon cultivation in Hg but the presence of Proteobacteria increased with Hg, whereas Bacteroidetes, Actinobacteria, Verrumicrobia, and Cyanobacteria were negatively impacted. Overall, the above findings suggest that the examination of the algal community composition might be used as a potential biomonitoring tool to assess the impacts of environmental Hg concentrations on aquatic systems, which would merit further investigation.

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“…Currently, there is only limited information about biofilm composition alteration when exposed to contaminants released by chlor-alkali production plants. Among the few available studies, a high tolerance to Hg was observed in biofilms from the Gallego River (Spain) 9 , with the predominance of filamentous alga Oedognium in the Hg-contaminated site. High abundance of Hg specific resistance gene (merA) in microbial biofilms over Hg contamination gradient was found for the Idrijca River (Slovenia) 10 .…”

Section: Introductionmentioning

confidence: 99%

Biofilm composition in the Olt River (Romania) reservoirs impacted by a chlor-alkali production plant

Dranguet

Cosio

Faucheur

et al. 2017

Environ. Sci.: Processes Impacts

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Freshwater biofilms can be useful indicators of water quality and offer the possibility to assess contaminant effects at the community level. The present field study examines the effects of chlor-alkali plant effluents on the community composition of biofilms grown in the Olt River (Romania) reservoirs. The relationship between ambient water quality variables and community composition alterations was explored. Amplicon sequencing revealed a significant modification of the composition of microalgal, bacterial and fungal communities in the biofilms collected in the impacted reservoirs in comparison with those living in the uncontaminated control reservoir. The abundance corrected Simpson index showed lower richness and diversity in biofilms collected in the impacted reservoirs than in the control reservoir. The biofilm bacterial communities of the impacted reservoirs were characterized by the contaminant-tolerant Cyanobacteria and Bacteroidetes, whereas microalgal communities were predominantly composed of Bacillariophyta and fungal communities of Lecanoromycetes and Paraglomycetes. A principal component analysis revealed that major contaminants present in the waste water of the chlor-alkali production plant, i.e. Na, Ca, Cl and Hg, were correlated with the alteration of biofilm community composition in the impacted reservoirs. However, the biofilm composition was also influenced by water quality variables such as NO, SO, DOC and Zn from unknown sources. The results of the present study imply that, even when below the environmental quality standards, typical contaminants of chlor-alkali plant releases may affect biofilm composition and that their impacts on the microbial biodiversity might be currently overlooked.

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Influence of global change-related impacts on the mercury toxicity of freshwater algal communities

Cited by 20 publications

References 58 publications

Mercury bioavailability, transformations, and effects on freshwater biofilms

Mercury bioavailability, transformations, and effects on freshwater biofilms

Long-Term Effects of Mercury on Biofilms Grown in Contaminated Microcosms: A Pilot Study

Biofilm composition in the Olt River (Romania) reservoirs impacted by a chlor-alkali production plant

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