Influence of temperate mixed and deciduous tree covers on Hg concentrations and photoredox transformations in snow

Poulain, Alexandre J.; Roy, Virginie; Amyot, Marc

doi:10.1016/j.gca.2007.03.003

Cited by 38 publications

(69 citation statements)

References 44 publications

(46 reference statements)

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“…[268,269] Plants act as interceptors of Hg-bearing dusts and RGM. [270] Consequently, Hg deposition rates to soils under forests and grasslands are estimated to be respectively ,4-and 2-fold higher on average than to adjacent lake surfaces. [267] Photo-reduction and re-volatilisation rates of deposited Hg are also several-times lower under trees than from adjacent sun-exposed areas.…”

Section: Eastern Beaufort Sea Belugamentioning

confidence: 99%

“…[267] Photo-reduction and re-volatilisation rates of deposited Hg are also several-times lower under trees than from adjacent sun-exposed areas. [270] Soil organic matter content, which is closely allied to the degree and type of vegetation cover, is a strong controller of the Hg content of soils in the northern hemisphere because of the strong binding of various Hg chemical forms to organic matter. [269] Data on THg concentrations in Arctic soils are sparse.…”

Section: Eastern Beaufort Sea Belugamentioning

confidence: 99%

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The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

Douglas

Loseto²,

Macdonald³

et al. 2012

Environ. Chem.

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119

147

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Environmental context. Mercury, in its methylated form, is a neurotoxin that biomagnifies in marine and terrestrial foodwebs leading to elevated levels in fish and fish-eating mammals worldwide, including at numerous Arctic locations. Elevated mercury concentrations in Arctic country foods present a significant exposure risk to Arctic people. We present a detailed review of the fate of mercury in Arctic terrestrial and marine ecosystems, taking into account the extreme seasonality of Arctic ecosystems and the unique processes associated with sea ice and Arctic hydrology.Abstract. This review is the result of a series of multidisciplinary meetings organised by the Arctic Monitoring and Assessment Programme as part of their 2011 Assessment 'Mercury in the Arctic'. This paper presents the state-of-the-art knowledge on the environmental fate of mercury following its entry into the Arctic by oceanic, atmospheric and terrestrial pathways. Our focus is on the movement, transformation and bioaccumulation of Hg in aquatic (marine and fresh water) and terrestrial ecosystems. The processes most relevant to biological Hg uptake and the potential risk associated with Hg exposure in wildlife are emphasised. We present discussions of the chemical transformations of newly deposited or transported Hg in marine, fresh water and terrestrial environments and of the movement of Hg from air, soil and water environmental compartments into food webs. Methylation, a key process controlling the fate of Hg in most ecosystems, and the role of trophic processes in controlling Hg in higher order animals are also included. Case studies on Eastern Beaufort Sea beluga (Delphinapterus leucas) and landlocked Arctic char (Salvelinus alpinus) are presented as examples of the relationship between ecosystem trophic processes and biologic Hg levels. We examine whether atmospheric mercury depletion events (AMDEs) contribute to increased Hg levels in Arctic biota and provide information on the links between organic carbon and Hg speciation, dynamics and bioavailability. Long-term sequestration of Hg into non-biological archives is also addressed. The review concludes by identifying major knowledge gaps in our understanding, including:(1) the rates of Hg entry into marine and terrestrial ecosystems and the rates of inorganic and MeHg uptake by Arctic microbial and algal communities; (2) the bioavailable fraction of AMDE-related Hg and its rate of accumulation by biota and (3) the fresh water and marine MeHg cycle in the Arctic, especially the marine MeHg cycle.

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Section: Eastern Beaufort Sea Belugamentioning

confidence: 99%

Section: Eastern Beaufort Sea Belugamentioning

confidence: 99%

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

Douglas

Loseto²,

Macdonald³

et al. 2012

Environ. Chem.

Self Cite

119

147

View full text Add to dashboard Cite

show abstract

“…Louis et al, 2005;Dommergue et al, 2007;Faïn et al, 2007;Johnson et al, 2008;Sherman et al, 2010). Prior to revolatilization, the produced GEM may be reoxidized (Lalonde et al, 2003;Ferrari et al, 2004b;Poulain et al, 2004Poulain et al, , 2007bMann et al, 2005;Lahoutifard et al, 2006;Lin et al, 2006;Dommergue et al, 2007;Faïn et al, 2006Faïn et al, , 2007Faïn et al, , 2008. Furthermore, halides stabilize oxidized mercury within the snowpack (Lalonde et al, 2003;Ferrari et al, 2004b;Faïn et al, 2006Faïn et al, , 2008Bartels-Rausch et al, 2011;Mann et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, halides stabilize oxidized mercury within the snowpack (Lalonde et al, 2003;Ferrari et al, 2004b;Faïn et al, 2006Faïn et al, , 2008Bartels-Rausch et al, 2011;Mann et al, 2011). Revolatilization is also less active under canopies than in adjacent open areas (Poulain et al, 2007b;Nelson et al, 2008). Although multiple factors are responsible (Fatnassi et al, 2006;Poulain et al, 2007b;Yue et al, 2008), the primary factor is likely the canopy's shadowing effect (Poulain et al, 2007a, b), which diminishes photoreduction.…”

Section: Introductionmentioning

confidence: 99%

“…Revolatilization is also less active under canopies than in adjacent open areas (Poulain et al, 2007b;Nelson et al, 2008). Although multiple factors are responsible (Fatnassi et al, 2006;Poulain et al, 2007b;Yue et al, 2008), the primary factor is likely the canopy's shadowing effect (Poulain et al, 2007a, b), which diminishes photoreduction. It also seems likely that mercury is rendered unavailable for emission through burial by fresh snowfalls (Witherow and Lyons, 2008;Dommergue et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

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How relevant is the deposition of mercury onto snowpacks? – Part 2: A modeling study

Durnford¹,

Dastoor

Ryzhkov

et al. 2012

Atmos. Chem. Phys.

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Abstract. An unknown fraction of mercury that is deposited onto snowpacks is revolatilized to the atmosphere. Determining the revolatilized fraction is important since mercury that enters the snowpack meltwater may be converted to highly toxic bioaccumulating methylmercury. In this study, we present a new dynamic physically-based snowpack/meltwater model for mercury that is suitable for large-scale atmospheric models for mercury. It represents the primary physical and chemical processes that determine the fate of mercury deposited onto snowpacks. The snowpack/meltwater model was implemented in Environment Canada's atmospheric mercury model GRAHM. For the first time, observed snowpack-related mercury concentrations are used to evaluate and constrain an atmospheric mercury model. We find that simulated concentrations of mercury in both snowpacks and the atmosphere's surface layer agree closely with observations. The simulated concentration of mercury in both in the top 30 cm and the top 150 cm of the snowpack, averaged over 2005-2009, is predominantly below 6 ng L −1 over land south of 66.5°N but exceeds 18 ng L −1 over sea ice in extensive areas of the Arctic Ocean and Hudson Bay. The average simulated concentration of mercury in snowpack meltwater runoff tends to be higher on the Russian/European side (>20 ng L −1 ) of the Arctic Ocean than on the Canadian side (<10 ng L −1 ). The correlation coefficient between observed and simulated monthly mean atmospheric surface-level gaseous elemental mercury (GEM) concentrations increased significantly with the inclusion of the new snowpack/meltwater model at two of the three stations (midlatitude, subarctic) studied and remained constant at the third (arctic). Oceanic emissions are postulated to produce the observed summertime maximum in concentrations of surface-level atmospheric GEM at Alert in the Canadian Arctic and to generate the summertime volatility observed in these concentrations at both Alert and Kuujjuarapik on subarctic Hudson Bay, Canada. We find that the fraction of deposited mercury that is revolatilized from snowpacks increases with latitude from 39 % between 30 and 45°N, to 57 % from 45 to 60°N, 67 % from 60 to 66.5°N, and 75 % polewards of 66.5°N on an annual basis. Combining this latitudinal gradient with the latitudinally increasing coverage of snowpacks causes yearly net deposition as a fraction of gross deposition to decrease from 98 % between 30 and 45°N to 89 % between 45 and 60°N, 73 % between 60 and 66.5°N, and 44 % within the Arctic Circle. The yearly net deposition and net accumulation of mercury at the surface within the Arctic Circle north of 66.5°N are estimated at 153 and 117 Mg, respectively. We calculate that 58 and 50 Mg of mercury are deposited annually to the Arctic Ocean directly and indirectly via melting snowpacks, respectively. For terrestrial surfaces within the Arctic Circle, we find that 29 and 16 Mg of mercury are deposited annually directly and indirectly via melting snowpacks, respectively. Within the Arctic Circle, multi-s...

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A review of mercury concentration and deposition in snow in eastern temperate North America

Nelson

Fernandez

Kahl

2010

Hydrological Processes

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Abstract:Most published research evaluating total (wet C dry) mercury (Hg) open sites were 3Ð4 : 1 (conifers) and 2Ð1 : 1 (all forest types). Ratios of event throughfall to wet-only collections were 5Ð0 : 1 (conifers) and 3Ð8 : 1 (all forest types), exceeding the previously reported overall average of throughfall to wet-only for the growing season. Future research should standardize snow Hg sampling methods to address volatilization and dry deposition. Mechanisms contributing to variability in snow Hg deposition could be assessed by measuring particulate Hg and examining interannual and spatial patterns.

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Influence of temperate mixed and deciduous tree covers on Hg concentrations and photoredox transformations in snow

Cited by 38 publications

References 44 publications

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

How relevant is the deposition of mercury onto snowpacks? – Part 2: A modeling study

A review of mercury concentration and deposition in snow in eastern temperate North America

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