Microbial- and thiosulfate-mediated dissolution of mercury sulfide minerals and transformation to gaseous mercury
Vazquez-Rodriguez, Adiari I.
Hansel, Colleen M.
Lamborg, Carl H.
Santelli, Cara M.
Webb, Samuel M.
Brooks, Scott C.
MetadataShow full item record
KeywordMercury; Metacinnabar; Sulfur chemosynthesis; Thiobacillus; Thiosulfate; Mercury sulfide dissolution; Sulfur metabolism; Sulfur oxidation
Mercury (Hg) is a toxic heavy metal that poses significant environmental and human health risks. Soils and sediments, where Hg can exist as the Hg sulfide mineral metacinnabar (β-HgS), represent major Hg reservoirs in aquatic environments. Metacinnabar has historically been considered a sink for Hg in all but severely acidic environments, and thus disregarded as a potential source of Hg back to aqueous or gaseous pools. Here, we conducted a combination of field and laboratory incubations to identify the potential for metacinnabar as a source of dissolved Hg within near neutral pH environments and the underpinning (a)biotic mechanisms at play. We show that the abundant and widespread sulfur-oxidizing bacteria of the genus Thiobacillus extensively colonized metacinnabar chips incubated within aerobic, near neutral pH creek sediments. Laboratory incubations of axenic Thiobacillus thioparus cultures led to the release of metacinnabar-hosted Hg(II) and subsequent volatilization to Hg(0). This dissolution and volatilization was greatly enhanced in the presence of thiosulfate, which served a dual role by enhancing HgS dissolution through Hg complexation and providing an additional metabolic substrate for Thiobacillus. These findings reveal a new coupled abiotic-biotic pathway for the transformation of metacinnabar-bound Hg(II) to Hg(0), while expanding the sulfide substrates available for neutrophilic chemosynthetic bacteria to Hg-laden sulfides. They also point to mineral-hosted Hg as an underappreciated source of gaseous elemental Hg to the environment.
© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Microbiology 6 (2015): 596, doi:10.3389/fmicb.2015.00596.
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Craddock, Paul R.; Rouxel, Olivier J.; Ball, Lary A.; Bach, Wolfgang (2008-04)We have developed a technique for the accurate and precise determination of 34S/32S isotope ratios (δ34S) in sulfur-bearing minerals using solution and laser ablation multiple-collector inductively coupled plasma mass ...
Friedman, Carrie T. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1998-02)Stable sulfur isotopes (δ34S) and trace Co are analyzed in sulfide and sulfate minerals from six sample types collected from the TAG active mound, 26°N Mid-Atlantic Ridge. δ34S values range from 2.7 to 2O.9%, with sulfate ...
Characterization of an autotrophic sulfide-oxidizing marine Arcobacter sp. that produces filamentous sulfur Wirsen, Carl O.; Sievert, Stefan M.; Cavanaugh, Colleen M.; Molyneaux, Stephen J.; Ahmad, A.; Taylor, L. T.; DeLong, Edward F.; Taylor, Craig D. (American Society for Microbiology, 2002-01)A coastal marine sulfide-oxidizing autotrophic bacterium produces hydrophilic filamentous sulfur as a novel metabolic end product. Phylogenetic analysis placed the organism in the genus Arcobacter in the epsilon subdivision ...