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| Titel |
Impact of elevated CO2, water table, and temperature changes on CO2 and CH4 fluxes from arctic tundra soils |
| VerfasserIn |
Donatella Zona, Katherine Haynes, Douglas Deutschman, Emma Bryant, Katherine McEwing, Scott Davidson, Walter Oechel |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250103423
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| Publikation (Nr.) |
 EGU/EGU2015-2834.pdf |
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| Zusammenfassung |
| Large uncertainties still exist on the response of tundra C emissions to future climate due, in
part, to the lack of understanding of the interactive effects of potentially controlling variables
on C emissions from Arctic ecosystems. In this study we subjected 48 soil cores
(without active vegetation) from dominant arctic wetland vegetation types, to a
laboratory manipulation of elevated atmospheric CO2, elevated temperature, and
altered water table, representing current and future conditions in the Arctic for two
growing seasons. To our knowledge this experiment comprised the most extensively
replicated manipulation of intact soil cores in the Arctic. The hydrological status of the
soil was the most dominant control on both soil CO2 and CH4 emissions. Despite
higher soil CO2 emission occurring in the drier plots, substantial CO2 respiration
occurred under flooded conditions, suggesting significant anaerobic respirations in
these arctic tundra ecosystems. Importantly, a critical control on soil CO2 and CH4
fluxes was the original vascular plant cover. The dissolved organic carbon (DOC)
concentration was correlated with cumulative CH4 emissions but not with cumulative CO2
suggesting C quality influenced CH4 production but not soil CO2 emissions. An
interactive effect between increased temperature and elevated CO2 on soil CO2
emissions suggested a potential shift of the soils microbial community towards more
efficient soil organic matter degraders with warming and elevated CO2. Methane
emissions did not decrease over the course of the experiment, even with no input
from vegetation. This result indicated that CH4 emissions are not carbon limited
in these C rich soils. Overall CH4 emissions represented about 49% of the sum
of total C (C-CO2 + C-CH4) emission in the wet treatments, and 15% in the dry
treatments, representing a dominant component of the overall C balance from arctic soils. |
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