Photodegradation of dissolved organic matter in forested streams of the northern Great Lakes region

2007 ◽  
Vol 26 (3) ◽  
pp. 416-425 ◽  
Author(s):  
James H. Larson ◽  
Paul C. Frost ◽  
David M. Lodge ◽  
Gary A. Lamberti
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Great Lakes ◽  
Great Lakes Region

scholarly journals Trends in dissolved organic matter cycling, sediment microbiomes, and methylmercury production across vegetation heterogeneity in a Great Lakes wetland

2016 ◽  
Author(s):  
Emily B. Graham ◽  
Joseph E. Knelman ◽  
Rachel S. Gabor ◽  
Shon Schooler ◽  
Diane M. McKnight ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Great Lakes ◽  
Inorganic Mercury ◽  
River Estuary ◽  
Future Research ◽  
Great Lakes Region ◽  
Mercury Cycling ◽  
Microbiome Composition ◽  
Vegetation Heterogeneity

AbstractRecent advances have allowed for greater investigation into microbial regulation of mercury toxicity in the environment. In wetlands in particular, dissolved organic matter (DOM) may influence methylmercury (MeHg) production both through chemical interactions and through substrate effects on microbiomes. We conducted microcosm experiments in two disparate wetland environments (oligotrophic unvegetated and high-C vegetated sediments) to examine the impacts of plant leachate and inorganic mercury loadings (20 mg/L HgCl2) on microbiomes, DOM cycling, and MeHg production in the St. Louis River Estuary. Our research reveals the greater relative capacity for mercury methylation in vegetated over unvegetated sediments. Further, our work shows how mercury cycling in oligotrophic unvegetated sediments may be susceptible to DOM inputs in the St. Louis River Estuary: microcosms receiving leachate produced substantially more MeHg than unamended microcosms. We also demonstrate (1) changes in microbiome structure towardsClostridia, (2) metagenomic shifts toward fermentation, and (3) degradation of complex DOM; all of which coincide with elevated net MeHg production in unvegetated microcosms receiving leachate. Finally, we examine microbial operational taxonomic units (OTUs) classified as known potential methylators and identify important organisms for future research in the Great Lakes region. Together, our work shows the influence of wetland vegetation in controlling MeHg production in the Great Lakes region and provides evidence that this may be due to both enhanced microbial activity as well as differences in microbiome composition.

scholarly journals Oligotrophic wetland sediments susceptible to shifts in microbiomes and mercury cycling with dissolved organic matter addition

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4575 ◽  
Author(s):  
Emily B. Graham ◽  
Rachel S. Gabor ◽  
Shon Schooler ◽  
Diane M. McKnight ◽  
Diana R. Nemergut ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Inorganic Mercury ◽  
River Estuary ◽  
Great Lakes Region ◽  
Mercury Toxicity ◽  
Mercury Cycling ◽  
Microbiome Composition ◽  
Relative Capacity ◽  
Organic Matter Addition

Recent advances have allowed for greater investigation into microbial regulation of mercury toxicity in the environment. In wetlands in particular, dissolved organic matter (DOM) may influence methylmercury (MeHg) production both through chemical interactions and through substrate effects on microbiomes. We conducted microcosm experiments in two disparate wetland environments (oligotrophic unvegetated and high-C vegetated sediments) to examine the impacts of plant leachate and inorganic mercury loadings (20 mg/L HgCl2) on microbiomes and MeHg production in the St. Louis River Estuary. Our research reveals the greater relative capacity for mercury methylation in vegetated over unvegetated sediments. Further, our work shows how mercury cycling in oligotrophic unvegetated sediments may be susceptible to DOM inputs in the St. Louis River Estuary: unvegetated microcosms receiving leachate produced substantially more MeHg than unamended microcosms. We also demonstrate (1) changes in microbiome structure towardsClostridia, (2) metagenomic shifts toward fermentation, and (3) degradation of complex DOM; all of which coincide with elevated net MeHg production in unvegetated microcosms receiving leachate. Together, our work shows the influence of wetland vegetation in controlling MeHg production in the Great Lakes region and provides evidence that this may be due to both enhanced microbial activity as well as differences in microbiome composition.

Dissolved Organic Matter in the Great Lakes: Role and Nature of Allochthonous Material

2008 ◽  
Vol 34 (3) ◽  
pp. 383-394 ◽  
Author(s):  
Véronique P. Hiriart-Baer ◽  
Ngan Diep ◽  
Ralph E. H. Smith
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Great Lakes
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