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| Titel |
CO2 evolution in highland soils of different land cover types in Iceland |
| VerfasserIn |
Utra Mankasingh, Guðrún Gísladóttir, Johann Thorsson, Minna Palomaki |
| 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 |
250113736
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| Publikation (Nr.) |
 EGU/EGU2015-13955.pdf |
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| Zusammenfassung |
| Soil respiration is a key ecosystem process that releases carbon from soil as CO2. Soil CO2
emission is sensitive to temperature, moisture and disturbance and is influenced by land use
and land cover change, especially in the upper soil organic layer. Release of CO2 from
soils of the south Icelandic highlands (318 - 356 m above sea level) was studied to
observe soil respiration in different land cover types and to quantify soil C lost as
CO2.
In a laboratory incubation study, exponential release of CO2 from soils was observed (>6
months) for the field moist soils collected from the highlands. Soils were collected at 12 sites
from the land cover types (plant communities) in September 2013. The land cover
types, categorized by plant communities, were: grasslands (G1-G8), with moss,
Carex Bigelowii and dwarf shrubs; a sandy fluvial wetland (S), and unvegetated
gravels (M1-M3). Since this experiment was conducted at 25Ë C whilst the observed
annual average temperature was 1.5 Ë C (Vatnsfell, 10 year average), this experiment
presents an accelerated picture of CO2 released from soils over a much longer time
period. For most soils, the rate of release decreased after 5 days. For all land cover
types, the CO2 release was greatest in the topspoil and this decreased with depth.
Soils with the highest % organic matter (G sites characterized by mosses and few
vascular species) appear to release the most CO2. In the top 5 cm, the CO2 emissions
follow the trend: grasslands (G1-G8)> sandy fluvial wetland (S) > unvegetated sites
(M1-M3). This trend appears to be related to the amount of organic matter present. For
all sites, the less than 250 mg CO2 was lost per kg of soil after 75 days, which is
equivalent to losing less than 69 mg C per kg soil, and represented less than 0.5% of the
total carbon present in any soil; less than 360 mg CO2 was lost after 260 days. |
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