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| Titel |
Three representative UK moorland soils show differences in decadal release of dissolved organic carbon in response to environmental change |
| VerfasserIn |
M. I. Stutter, D. G. Lumsdon, A. P. Rowland |
| 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 ; 8, no. 12 ; Nr. 8, no. 12 (2011-12-14), S.3661-3675 |
| Datensatznummer |
250006247
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| Publikation (Nr.) |
 copernicus.org/bg-8-3661-2011.pdf |
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| Zusammenfassung |
| Moorland carbon reserves in organo-mineral soils may be crucial to
predicting landscape-scale variability in soil carbon losses, an important
component of which is dissolved organic carbon (DOC). Surface water DOC
trends are subject to a range of scaling, transport and biotic processes
that disconnect them from signals in the catchment's soils. Long-term soil
datasets are vital to identify changes in DOC release at source and soil C
depletion. Here we show, that moorland soil solution DOC concentrations at
three key UK Environmental Change Network sites increased between 1993–2007
in both surface- and sub- soil of a freely-draining Podzol (48 % and
215 % increases in O and Bs horizons, respectively), declined in a gleyed
Podzol and showed no change in a Peat. Our principal findings were that: (1) considerable
heterogeneity in DOC response appears to exist between
different soils that is not apparent from the more consistent observed
trends for streamwaters, and (2) freely-draining organo-mineral Podzol
showed increasing DOC concentrations, countering the current scientific
focus on soil C destabilization in peats. We discuss how the key solubility
controls on DOC associated with coupled physico-chemical factors of ionic
strength, acid deposition recovery, soil hydrology and temperature cannot
readily be separated. Yet, despite evidence that all sites are recovering
from acidification the soil-specific responses to environmental change have
caused divergence in soil DOC concentration trends. The study shows that the
properties of soils govern their specific response to an approximately
common set of broad environmental drivers. Key soil properties are indicated
to be drainage, sulphate and DOC sorption capacity. Soil properties need
representation in process-models to understand and predict the role of soils
in catchment to global C budgets. Catchment hydrological (i.e. transport)
controls may, at present, be governing the more ubiquitous rises in river
DOC concentration trends, but soil (i.e. source) controls provide the key to
prediction of future C loss to waters and the atmosphere. |
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