Isotopic methods for non-destructive assessment of carbon dynamics in shrublands under long-term climate change manipulation
Andresen, Louise C. (University of Amsterdam. Institute for Biodiversity and Ecosystem Dynamics)
Domínguez, Maria T. (Centre for Ecology and Hydrology (UK))
Reinsch, Sabine (Centre for Ecology and Hydrology (UK))
Smith, Andrew R. (Centre for Ecology and Hydrology (UK))
Schmidt, Inger K. (University of Copenhagen. Department of Geosciences and Natural Resource Management)
Ambus, Per (University of Copenhagen. Department of Geosciences and Natural Resource Management)
Beier, Claus (Norwegian Institute for Water Research. Centre for Catchments and Urban Water Research)
Boeckx, Pascal (Ghent University. Isotope Bioscience Laboratory)
Bol, Roland (University of Amsterdam. Institute for Biodiversity and Ecosystem Dynamics)
de Dato, Giovanbattista (University of Tuscia. Department for Innovation in Biological, Agro-food and Forest systems)
Emmett, Bridget A. (Centre for Ecology and Hydrology (UK))
Estiarte, Marc (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Garnett, Mark H. (NERC Radiocarbon Facility (UK))
Kröel-Dulay, György (Hungarian Academy of Sciences. Institute of Ecology and Botany)
Mason, Sharon L. (University of Amsterdam. Institute for Biodiversity and Ecosystem Dynamics)
Nielsen, Cecilie S. (Swedish University of Agricultural Sciences. Department of Forest Ecology and Management)
Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Tietema, Albert (University of Amsterdam. Institute for Biodiversity and Ecosystem Dynamics)

Data:	2018
Resum:	Long-term climate change experiments are extremely valuable for studying ecosystem responses to environmental change. Examination of the vegetation and the soil should be non-destructive to guarantee long-term research. In this paper, we review field methods using isotope techniques for assessing carbon dynamics in the plant-soil-air continuum, based on recent field experience and examples from a European climate change manipulation network. Eight European semi-natural shrubland ecosystems were exposed to warming and drought manipulations. One field site was additionally exposed to elevated atmospheric CO2. We discuss the isotope methods that were used across the network to evaluate carbon fluxes and ecosystem responses, including: (1) analysis of the naturally rare isotopes of carbon (13C and 14C) and nitrogen (15N); (2) use of in situ pulse labelling with 13CO2, soil injections of 13C- and 15N-enriched substrates, or continuous labelling by free air carbon dioxide enrichment (FACE) and (3) manipulation of isotopic composition of soil substrates (14C) in laboratory-based studies. The natural 14C signature of soil respiration gave insight into a possible long-term shift in the partitioning between the decomposition of young and old soil carbon sources. Contrastingly, the stable isotopes 13C and 15N were used for shorter-term processes, as the residence time in a certain compartment of the stable isotope label signal is limited. The use of labelled carbon-compounds to study carbon mineralisation by soil micro-organisms enabled to determine the long-term effect of climate change on microbial carbon uptake kinetics and turnover. Based on the experience with the experimental work, we provide recommendations for the application of the reviewed methods to study carbon fluxes in the plant-soil-air continuum in climate change experiments. 13C-labelling techniques exert minimal physical disturbances, however, the dilution of the applied isotopic signal can be challenging. In addition, the contamination of the field site with excess 13C or 14C can be a problem for subsequent natural abundance (14C and 13C) or label studies. The use of slight changes in carbon and nitrogen natural abundance does not present problems related to potential dilution or contamination risks, but the usefulness depends on the fractionation rate of the studied processes.
Ajuts:	Ministerio de Economía y Competitividad CGL2016-79835-P Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-274 European Commission 610028
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	C ; Bomb-C ; Drought ; Free air carbon dioxide enrichment ; Pulse-labelling ; Stable isotopes ; Warming
Publicat a:	Methods in Ecology and Evolution, Vol. 9, Issue 4 (April 2018) , p. 866-880, ISSN 2041-210X

DOI: 10.1111/2041-210X.12963

Postprint 16 p, 1.6 MB

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