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

Environments

Aline Freiburghaus¹  VeraI. Slaveykova¹  Séverine Le Faucheur¹  Perrine Dranguet¹ 

[1] Faculty of Sciences, Section of Earth and Environmental Sciences, Department F.-A. Forel for Environmental and Aquatic Sciences, Environmental Biogeochemistry and Ecotoxicology group, University of Geneva, Uni Carl Vogt, 66 Blvd Carl-Vogt, CH 1211 Geneva, Switzerland;

关键词: periphyton;    bioaccumulation;    taxonomy;    methylmercury;    bacteria;    microalgae;   

DOI  :  10.3390/environments6030028

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown