The Microbial Ecology of Mercury Methylation and Demethylation in the Florida Everglades

2015 ◽  
pp. 385-395
2011 ◽  
Vol 71-78 ◽  
pp. 3201-3206
Author(s):  
Yu Xiang Mao ◽  
Hai Lin Wang ◽  
Mei Wang

Methylmercury (MeHg) production from inorganic mercury in natural environment leads to bioaccumulation in fish, putting human being under the risk of exposure. This study investigated the transformation of enriched stable isotope tracer,199Hg2+, in sediment slurry of the Florida Everglades. Incubation experiments were conducted under four different laboratory conditions. The results suggest that methylation of mercury mainly happened under anaerobic condition, with microbial activity playing the major role. The relative methylation rate was determined to be 1% per day at the first few days, and then this transformation process slowed down. At the end of incubation experiment, totally around 20% of the isotope tracer199Hg2+was transformed to its methylated form, Me199Hg. This high potential of mercury methylation partially accounts for the contamination and bioaccumulation of MeHg in the relatively pristine Florida Everglades ecosystem.


1999 ◽  
Vol 44 (7) ◽  
pp. 1815-1825 ◽  
Author(s):  
Lisa B. Cleckner ◽  
Cynthia C. Gilmour ◽  
James P. Hurley ◽  
David P. Krabbenhoft

2014 ◽  
Vol 80 (20) ◽  
pp. 6517-6526 ◽  
Author(s):  
Hee-Sung Bae ◽  
Forrest E. Dierberg ◽  
Andrew Ogram

ABSTRACTThe mechanisms and rates of mercury methylation in the Florida Everglades are of great concern because of potential adverse impacts on human and wildlife health through mercury accumulation in aquatic food webs. We developed a new PCR primer set targetinghgcA, a gene encoding a corrinoid protein essential for Hg methylation across broad phylogenetic boundaries, and used this primer set to study the distribution ofhgcAsequences in soils collected from three sites along a gradient in sulfate and nutrient concentrations in the northern Everglades. The sequences obtained were distributed in diverse phyla, includingProteobacteria,Chloroflexi,Firmicutes, andMethanomicrobia; however,hgcAclone libraries from all sites were dominated by sequences clustering within the orderSyntrophobacteralesof theDeltaproteobacteria(49 to 65% of total sequences).dsrBmRNA sequences, representing active sulfate-reducing prokaryotes at the time of sampling, obtained from these sites were also dominated bySyntrophobacterales(75 to 89%). Laboratory incubations with soils taken from the site low in sulfate concentrations also suggested that Hg methylation activities were primarily mediated by members of the orderSyntrophobacterales, with some contribution by methanogens,Chloroflexi, iron-reducingGeobacter, and non-sulfate-reducingFirmicutesinhabiting the sites. This suggests that prokaryotes distributed within clades defined by syntrophs are the predominant group controlling methylation of Hg in low-sulfate areas of the Everglades. Any strategy for managing mercury methylation in the Everglades should consider that net mercury methylation is not limited to the action of sulfate reduction.


2008 ◽  
Vol 53 (1) ◽  
pp. 3-11 ◽  
Author(s):  
J Kuparinen ◽  
H Galvão
Keyword(s):  

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