Molecular correlations of dissolved organic matter with inorganic mercury and methylmercury in Canadian boreal streams

Mangal, Vaughn; Lam, Wai Ying; Huang, Huogao; Emilson, Erik J. S.; Mackereth, Robert W.; Mitchell, Carl P. J.

doi:10.1007/s10533-022-00944-6

Cited by 6 publications

(7 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We found stronger associations of MeHg‐DOM in the peatland catchment, while THg‐DOM was more strongly correlated in the mixed catchment. Similarly, global assessments have found THg‐DOM relationships to be typically stronger than MeHg‐DOM in surface waters (Lavoie et al., 2019; Wu et al., 2022), although more robust coupling between MeHg and aromatic DOM has been observed in wetland‐influenced boreal streams, with some seasonal variability (Fink‐Mercier, del Giorgio, et al., 2022; Mangal et al., 2022).…”

Section: Discussionmentioning

confidence: 96%

“…Anoxic, acidic, DOC‐rich conditions support the microbial methylation of inorganic divalent Hg II into MeHg, making peatlands ideal methylation sites (Bravo & Cosio, 2020; Gordon et al., 2016; Poulin et al., 2019). Higher in situ methylation efficiency has been linked to the presence of bioavailable Hg II and labile dissolved organic matter (DOM), whereas MeHg bound to aromatic DOM has been linked to longer‐range transport in boreal surface waters (Bravo et al., 2017; Mangal et al., 2022; Shanley et al., 2022). Permafrost peatlands have accumulated large Hg stores bound to organic matter (Lim et al., 2020; Schuster et al., 2018), and non‐permafrost peatlands are hotspots of MeHg production across the global boreal‐Arctic (Gordon et al., 2016; Poulin et al., 2019; Tarbier et al., 2021).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Concentrations and Yields of Mercury, Methylmercury, and Dissolved Organic Carbon From Contrasting Catchments in the Discontinuous Permafrost Region, Western Canada

Thompson,

Low,

Shewan

et al. 2023

Water Resources Research

View full text Add to dashboard Cite

Climate change and permafrost thaw may impact the mobilization of terrestrial dissolved organic carbon (DOC), mercury (Hg), and neurotoxic methylmercury (MeHg) into aquatic ecosystems; thus, understanding processes that control analyte export in northern catchments is needed. We monitored water chemistry for 3 years (2019–2021) at a peatland catchment (Scotty Creek) and a mixed catchment (Smith Creek) in the Dehcho (Northwest Territories), within the discontinuous permafrost zone of boreal western Canada. The peatland catchment had higher DOC and dissolved MeHg, but lower total Hg concentrations (mean ± standard deviation; 19 ± 2.6 mg DOC L−1; 0.08 ± 0.04 ng DMeHg L−1; 1.1 ± 0.3 ng THg L−1) than the mixed catchment (12 ± 4.4 mg DOC L−1; 0.05 ± 0.01 ng DMeHg L−1; 3.1 ± 2.2 ng THg L−1). Analyte concentrations increased with discharge at the mixed catchment, suggesting transport limitation and the flushing of near‐surface, organic‐rich flow paths during wet periods. In contrast, analyte concentrations in the peatland catchment were not primarily associated with discharge. MeHg concentrations, MeHg:THg, and MeHg:DOC increased with water temperature, suggesting enhanced Hg methylation during warmer periods. Mean open water season DOC and total MeHg yields were greater and more variable from the peatland than the mixed catchment (1.1–6.6 vs. 1.4–2.4 g DOC m−2; 5.2–36 vs. 6.1–10 ng MeHg m−2). Crucial storage thresholds controlling runoff generation likely drove greater inter‐annual variability in analyte yields from the peatland catchment. Our results suggest climate change may influence the production and transport of MeHg from boreal‐Arctic catchments as temperatures increase, peatlands thaw, and runoff generation is altered.

show abstract

Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Concentrations and Yields of Mercury, Methylmercury, and Dissolved Organic Carbon From Contrasting Catchments in the Discontinuous Permafrost Region, Western Canada

Thompson,

Low,

Shewan

et al. 2023

Water Resources Research

View full text Add to dashboard Cite

show abstract

“…A Pearson correlation heatmap equipped with Bray–Curtis hierarchical clustering was conducted to relate FT-ICR-MS properties, water quality parameters, and absorbance metrics of DOM across different watersheds. Finally, a Spearman's rho ( ρ ) relating the relative abundances of different DOM molecules to watershed characteristics and land cover was conducted using a custom script R. 42 A total of 999 permutations were conducted to remove false positive findings, and significant correlations were observed when p < 0.05. Using a van-Krevelen space, we plotted significantly correlating molecules to relate DOM molecules changing in abundance in relation to different watershed characteristics and land cover properties.…”

Section: Methodsmentioning

confidence: 99%

Emerging investigator series: impacts of land use on dissolved organic matter quality in agricultural watersheds: a molecular perspective

A.,

T.,

2024

Environ. Sci.: Processes Impacts

View full text Add to dashboard Cite

show abstract

“…Beaver ponds create temporary wetlands, which have long been thought of as ideal environments for Hg methylation (Chen et al 2012, Tjerngren et al 2012 due to (a) the flooding of labile organic carbon (Hall et al 2005), (b) the subsequent anoxic conditions (St. Louis et al 1994, Driscoll et al 1998 and (c) the higher and more stable water temperature (Collen and Gibson 2000, Sun et al 2023, all favouring microbial activity. Beavers also continually add fresh organic matter to the inundated area via direct delivery for food and dam construction (Johnston 2017) as well as by creating foraging canals around the pond that facilitate additional transport of upland material (Grudzinski et (Mangal et al 2022). However, as these processes occur on a small scale when compared to overall watershed factors, the overall downstream increase in MeHg is small.…”

Section: Upstream In-pond and Downstream Water Chemistrymentioning

confidence: 99%

Landscape characteristics govern the impacts of beaver ponds on surface water methylmercury concentrations in boreal watersheds

Lam,

Mackereth,

Mitchell

2024

Environ. Res.: Ecology

View full text Add to dashboard Cite

Studies in boreal regions concerning the bioaccumulative neurotoxin methylmercury (MeHg) in natural wetlands and experimental reservoirs have shown that these waterbodies contribute to high MeHg levels in underlying sediments, inundated vegetation, and aquatic organisms. Beaver ponds are natural reservoirs that are ubiquitous in the Canadian boreal region and have been reported to increase downstream MeHg concentrations. However, the reported impacts of beaver ponds on stream MeHg vary widely across a limited number of studies, and factors influencing this variation are not well understood. To quantify the effect of beaver ponds on stream mercury concentrations, water samples were taken upstream and downstream of 10 in-channel beaver impoundments in northwestern Ontario, Canada. The downstream:upstream MeHg concentration ratios were related to pond and landscape characteristics to examine potential factors that play a role in determining the effect of beaver ponds on stream MeHg concentrations. Overall, MeHg concentrations were 1.6 times greater downstream of the beaver ponds, though this increase was not consistent; downstream concentrations up to 12 times greater and up to 5 times less were also observed. Landscape characteristics that can be readily obtained from existing spatial datasets or quantified using remote sensing techniques emerged as better predictors of downstream:upstream MeHg concentrations than site-specific stream chemistry parameters or pond characteristics that are more difficult to ascertain, with drier landscapes indicative of lower background MeHg export being more likely to exhibit greater increases in MeHg downstream of a beaver pond. These results suggest that the effects of beaver ponds on surface water MeHg concentrations are generally small but highly variable, and that the magnitude of the pond’s influence on stream MeHg are lessened in landscapes already conducive to higher MeHg concentrations.

show abstract

Molecular correlations of dissolved organic matter with inorganic mercury and methylmercury in Canadian boreal streams

Cited by 6 publications

References 78 publications

Concentrations and Yields of Mercury, Methylmercury, and Dissolved Organic Carbon From Contrasting Catchments in the Discontinuous Permafrost Region, Western Canada

Concentrations and Yields of Mercury, Methylmercury, and Dissolved Organic Carbon From Contrasting Catchments in the Discontinuous Permafrost Region, Western Canada

Emerging investigator series: impacts of land use on dissolved organic matter quality in agricultural watersheds: a molecular perspective

Landscape characteristics govern the impacts of beaver ponds on surface water methylmercury concentrations in boreal watersheds

Contact Info

Product

Resources

About