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| Titel |
Modelling the sensitivity of soil mercury storage to climate-induced changes in soil carbon pools |
| VerfasserIn |
O. Hararuk, D. Obrist, Y. Luo |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 4 ; Nr. 10, no. 4 (2013-04-10), S.2393-2407 |
| Datensatznummer |
250018192
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| Publikation (Nr.) |
 copernicus.org/bg-10-2393-2013.pdf |
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| Zusammenfassung |
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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