Journalartikel

Jahr der Veröffentlichung: 2016

Seiten: 963-972

Zeitschrift: Rapid Communications in Mass Spectrometry

Bandnummer: 30

Heftnummer: 7

ISSN: 0951-4198

eISSN: 1097-0231

DOI Link: https://doi.org/10.1002/rcm.7515

Verlag: Wiley

Abstract: 
RationaleBecause of the wide-ranging appearance and high soil organic carbon (C) content of grasslands, their ecosystems play an important role in the global C cycle. Thus, even small changes in input or output rates lead to significant changes in the soil C content, thereby affecting atmospheric [CO2]. Our aim was to examine if a higher C supply provided under elevated CO2 will increase the soil C pool. Special attention was given to respirational processes, where CO2 emission rates and its sources (plant vs. soil) were considered.MethodsThe Giessen-FACE experiment started in 1998 with a moderate CO2 enrichment of +20% and +30% above ambient on an extensively managed grassland. The experiment consists of three control plots where no CO2 is applied, three plots where [CO2] is enriched by +20% and one plot receiving [CO2] +30%. To exclude initial CO2 step increase effects, a detailed examination of respirational processes over 30months was carried out after 6years of CO2 enrichment starting in June 2004. At that time, the C-13 signature of the enrichment-CO2 was switched from -25 to -48 without a concomitant change in CO2 concentration.ResultsAfter 9years, the fraction of new C under [CO2] +20% was 37 +/- 5.4% in the top 7.5cm but this decreased with depth. No CO2 effect on soil carbon content was detected. Between June 2004 and December 2006, elevated [CO2] +20% increased the ecosystem respiration by 13%. The contribution of root respiration to soil respiration was 37 +/- 13% (5cm) and 43 +/- 14% (10cm) for [CO2] +20% and 35 +/- 13% and 40 +/- 13% for [CO2] +30%, respectively.ConclusionsOur findings of an increased C turnover without a net soil C sequestration suggest that the sink strength of grassland ecosystems might decrease in the future, because the additional C may quickly be released as CO2 to the atmosphere. Copyright (c) 2016 John Wiley & Sons, Ltd.

Harvard-Zitierstil: Lenhart, K., Kammann, C., Boeckx, P., Six, J. and Müller, C. (2016) Quantification of ecosystem C dynamics in a long-term FACE study on permanent grassland, Rapid Communications in Mass Spectrometry, 30(7), pp. 963-972. https://doi.org/10.1002/rcm.7515

APA-Zitierstil: Lenhart, K., Kammann, C., Boeckx, P., Six, J., & Müller, C. (2016). Quantification of ecosystem C dynamics in a long-term FACE study on permanent grassland. Rapid Communications in Mass Spectrometry. 30(7), 963-972. https://doi.org/10.1002/rcm.7515