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| Titel |
Interdependencies between temperature and moisture sensitivities of CO2 emissions in European land ecosystems |
| VerfasserIn |
C. Gritsch, M. Zimmermann, S. Zechmeister-Boltenstern |
| 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 ; 12, no. 20 ; Nr. 12, no. 20 (2015-10-21), S.5981-5993 |
| Datensatznummer |
250118132
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| Publikation (Nr.) |
 copernicus.org/bg-12-5981-2015.pdf |
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| Zusammenfassung |
Soil respiration is one of the largest terrestrial fluxes of carbon dioxide
(CO2) to the atmosphere. Hence, small changes in soil respiration rates
could have large effects on atmospheric CO2. In order to assess
CO2 emissions from diverse European soils with different land-use types and
climate (soil moisture and temperature), we conducted a laboratory incubation
experiment.
Emission measurements of CO2 under controlled conditions were
conducted using soil monoliths of nine sites from a European flux network
(ÉCLAIRE). The sites are located all over Europe – from the United Kingdom in
the west to Ukraine in the east, and from Italy in the south to Finland in the
north – and can be separated according to four land-use types (forests, grasslands,
arable lands and one peatland). Intact soil cores were incubated in the
laboratory in a two-way factorial design, with temperature (5, 10, 15, 20
and 25 °C) and water-filled pore space (WFPS; 5, 20, 40, 60 and 80 %) as the independent variables, while CO2 flux was the
response variable. The latter was measured with an automated laboratory
incubation measurement system.
Land use generally had a substantial influence on carbon dioxide fluxes,
with the order of CO2 emission rates of the different land-use types being
grassland > peatland > forest/arable land
(P < 0.001). CO2 efflux responded strongly to varying
temperature and moisture content with optimum moisture contents for CO2
emissions between 40 and 70 % WFPS and a positive relationship between
CO2 emissions and temperature. The relationship between temperature and
CO2 emissions could be well described by a Gaussian model. Q10
values ranged between 0.86 and 10.85 and were negatively related to
temperature for most of the moisture contents and sites investigated. At
higher temperatures the effect of water and temperature on Q10 was very
low. In addition, under cold temperatures Q10 varied with moisture
contents, indicating a stronger prospective effect of rain events in cold
areas on temperature sensitivity. At both coniferous forest sites we found a
strong increase in the temperature sensitivity at a moisture range between
20 and 40 % WFPS.
We developed a new approach to calculate moisture sensitivity (MS) of
CO2 efflux. MS was calculated as the slope of a polynomial function of
second degree. Moisture sensitivities were highest under dry and wet
conditions. In addition we found a positive relationship between MS of
CO2 efflux and temperature for both arable lands. |
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