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| Titel |
Drying-induced consolidation, organic matter decomposition, and
restructuring of soil aggregates |
| VerfasserIn |
Asmeret Asefaw Berhe, Chelsea Arnold, Teamrat A. Ghezzehei |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147341
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| Publikation (Nr.) |
 EGU/EGU2017-11494.pdf |
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| Zusammenfassung |
| While peatlands are garnering much attention for their greenhouse gas feedback potential in a
warming climate, the coupled biogeochemical and hydrological impact of structural and
physical changes in these types of systems as a result of drought-induced drying and
desiccation has not been studied in detail. The cyclic drawdown/recharge of the water table
that exists in most peatland systems impose important controls on organic matter
storage and decomposition as well as soil physical properties. In order to better
understand how high elevation peatlands will respond to increasingly dry years, we
incubated meadow soils collected along a hydrologic gradient at 5 different water
potentials and measured the CO2 flux at intervals for over one year to determine
how desiccation of meadow soils (from the Harvey Monroe Hall Research Natural
Area at the crest of the Sierra Nevada) influences gaseous fluxes of C, as well as
aggregation of the organic-rich soils and distribution of the soil C in different physical
pools (macro- vs. micro-aggregate, and silt+ clay fractions). We found that the
cumulative carbon mineralization was greatest at the highest (0.1 bar) and lowest (4 bar)
water potential, across all regions of the meadow, indicating the presence of two
separate pools of labile carbon that can be accessed only after a threshold of drying is
reached in the soil. We also observe important changes associated with aggregate
size distributions and fraction of total carbon distributed in three distinct pools. |
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