Mercury distribution in two Sierran forest and one desert sagebrush steppe ecosystems and the effects of fire

Engle, Mark A.; Gustin, Mae Sexauer; Johnson, Dale W.; Murphy, James; Miller, W. W.; Walker, R. F.; Wright, J. Michael; Markee, Melissa

doi:10.1016/j.scitotenv.2005.11.025

Cited by 91 publications

(110 citation statements)

References 38 publications

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“…5) which indicates that fires and subsequent changes in vegetation and possibly ecosystem productivity have not -or possibly not yet -affected the underlying soil Hg pools. This is in full agreement with the literature which reports negligible losses of soil Hg during wildfires (Engle et al, 2006). However, above-ground pools at both sites were affected by fires and showed only about half of the Hg pools of the adjacent intact sites (45% and 52% lower for the Lake Tahoe and the Truckee site, respectively; Fig.…”

Section: Effects Of Fires On C and Hg Poolssupporting

confidence: 93%

“…Grigal (2003) reviewed a series of studies reporting bole wood concentrations between 2 to 13 µg kg −1 with concentrations in the north-central part of the USA ranging from 0.6 to 12 µg kg −1 (with 60% of the values in the ranging between 1 to 4 µg kg −1 ). Engle et al (2006) report bole wood concentrations in the same Truckee site as this study of 2.9 µg kg −1 . The lower concentrations measured in our study could be due to the remote location of the Sierra Nevada.…”

Section: Above-ground Hg Concentrationsmentioning

confidence: 79%

“…Most ecosystem Hg resides in soils (upper 40 cm) which accounts for 94 to 98% of the total ecosystem Hg pools across all sites. The notion that soils represent the dominant ecosystem Hg pools has been reported for a number of sites; two boreal forest stands in Canada showed 93 to 97% of the total ecosystem Hg pools to reside in the soils (Friedli et al, 2007), and Engle et al (2006) reported over 90% of ecosystem Hg in soil in similar Sierra Nevada forest sites and in a desert sagebrush steppe site. There were significant differences in soil Hg pools between the sites located in Little Valley and those near Truckee, and since soils represent the vast pools at each site these differences also show at the total ecosystem level.…”

Section: Soil Hg Concentrations and Relationship To Soil C And Nmentioning

confidence: 94%

“…3 Aastrup et al (1991) reported declining Hg concentrations from mor horizons to B and C horizons (from 250 to 6 µg kg −1 ) in a pine/spruce forest in Sweden; soil concentrations decreased sharply with depth in mineral horizons in coniferous and deciduous forests in Germany (Schwesig and Matzer, 2000); sites in central Minnesota showed marked declines from the top 0-10 cm to 10-50 cm depth (from 36 to 11 µg kg −1 ; Grigal et al, 1994);and Engle et al (2006) reported decreasing Hg concentrations in two Sierra Nevada forest sites with highest Hg concentrations in the top A horizons. Exceptions to these patterns have been reported in podzolic and chernozemic soils where leaching and accumulation horizons of organic matter and sesqui-oxides are believed to cause different depth distribution of Hg (Schwesig and Matzner, 2000;Dudas and Pawluk, l976).…”

Section: Soil Hg Concentrations and Relationship To Soil C And Nmentioning

confidence: 99%

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Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

2009

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Abstract. This study presents data on mercury (Hg) concentrations, stochiometric relations to carbon (C) and nitrogen (N), and Hg pool sizes in four Sierra Nevada forest sites of similar exposure and precipitation regimes, and hence similar atmospheric deposition, to evaluate how ecosystem parameters control Hg retention in ecosystems. In all four sites, the largest amounts of Hg reside in soils which account for 94-98% of ecosystem pools. Hg concentrations and Hg/C ratios increase in the following order: Green Needles/Leaves

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Section: Effects Of Fires On C and Hg Poolssupporting

confidence: 93%

Section: Above-ground Hg Concentrationsmentioning

confidence: 79%

Section: Soil Hg Concentrations and Relationship To Soil C And Nmentioning

confidence: 94%

Section: Soil Hg Concentrations and Relationship To Soil C And Nmentioning

confidence: 99%

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Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

2009

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“…Figure 2b shows predicted soil Hg densities for the continental US, and Fig. 2d shows predicted soil Hg densities and observed Hg densities at 14 field observation sites plus additional published data found in sites across the US (Stamenkovic et al, 2008;Ma et al, 1997;Obrist et al, 2011;Amirbahman et al, 2004;Cohen et al, 2009;Demers et al, 2007;Dicosti et al, 2006;Dreher and Follmer, 2004;Grigal, 2003;Engle et al, 2006;Nater and Grigal, 1992;Natali et al, 2008). On average, observed and predicted soil Hg densities were within 15.6 % of each other (r = 0.47, P = 0.024).…”

Section: Model Evaluation and Comparisons To Observationsmentioning

confidence: 76%

Modelling the sensitivity of soil mercury storage to climate-induced changes in soil carbon pools

2013

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Substantial amounts of mercury (Hg) in the terrestrial environment reside in soils and are associated with soil organic carbon (C) pools, where they accumulated due to increased atmospheric deposition resulting from anthropogenic activities. The purpose of this study was to examine potential sensitivity of surface soil Hg pools to global change variables, particularly affected by predicted changes in soil C pools, in the contiguous US. To investigate, we included a soil Hg component in the Community Land Model based on empirical statistical relationships between soil Hg / C ratios and precipitation, latitude, and clay; and subsequently explored the sensitivity of soil C and soil Hg densities (i.e., areal-mass) to climate scenarios in which we altered annual precipitation, carbon dioxide (CO₂) concentrations and temperature.

Our model simulations showed that current sequestration of Hg in the contiguous US accounted for 15 230 metric tons of Hg in the top 0–40 cm of soils, or for over 300 000 metric tons when extrapolated globally. In the simulations, US soil Hg pools were most sensitive to changes in precipitation because of strong effects on soil C pools, plus a direct effect of precipitation on soil Hg / C ratios. Soil Hg pools were predicted to increase beyond present-day values following an increase in precipitation amounts and decrease following a reduction in precipitation. We found pronounced regional differences in sensitivity of soil Hg to precipitation, which were particularly high along high-precipitation areas along the West and East Coasts. Modelled increases in CO₂ concentrations to 700 ppm stimulated soil C and Hg accrual, while increased air temperatures had small negative effects on soil C and Hg densities. The combined effects of increased CO₂, increased temperature and increased or decreased precipitation were strongly governed by precipitation and CO₂ showing pronounced regional patterns. Based on these results, we conclude that the combination of precipitation and CO₂ should be emphasised when assessing how climate-induced changes in soil C may affect sequestration of Hg in soils

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Mercury concentrations and pools in four adjacent coniferous and deciduous upland forests in Beijing, China

et al. 2017

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Understanding of forest mercury (Hg) pools is important for quantifying the global atmospheric Hg removal. We studied gaseous elemental Hg (GEM) concentrations, litterfall Hg depositions, and pool sizes in four adjacent stands at Mount Dongling to assess Hg dynamics in the forested catchment and the potential of Hg release during wildfires. The average GEM concentration was 2.5 ± 0.5 ng m−3, about 1.5 times of the background levels in the Northern Hemisphere. In all four stands, Hg concentrations increase in the following order: bole wood < branch/twig < bark < mineral soil < needles/leaves < litterfall < Oi litter < Oe soil < Oa organic soil. The Hg pools of aboveground biomass were comparable in the forests of larch, oak, and Chinese pine, which were much greater than that of mixed broadleaf stands due to lower biomass. The total Hg pools in ecosystems were similar in the four stands, because of the comparable Hg pool in the soil horizons (0–40 cm), which accounted for over 97% of the total ecosystem Hg storage in the four stands. Although Hg pools of the forest ecosystem in north China were comparable to North America and North Europe, Hg storage in forests constituted a high threat for large Hg emission pulses to the atmosphere by wildfires. The potential Hg emissions from the combustion at the four stands were ranged from 0.675 to 1.696 mg m−2.

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Mercury distribution in two Sierran forest and one desert sagebrush steppe ecosystems and the effects of fire

Cited by 91 publications

References 38 publications

Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

Modelling the sensitivity of soil mercury storage to climate-induced changes in soil carbon pools

Mercury concentrations and pools in four adjacent coniferous and deciduous upland forests in Beijing, China

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