Stable Isotope Laboratory

Lab overview

Stable isotope ratios of the light elements H, C, N and O can be used as a universal tool for studying physical, chemical and biological processes. We have 5 mass-spectrometers and dedicated periphery for the analysis of organic matter, gas samples (CO2 and CH4) and water samples. With HPLC and GC we apply compound-specific isotope ratio analysis of sugars and fatty acids.

Read more about the use of stable isotopes in ecosystem research...

Visit our lab:

Sample preparation and analysis

Most samples analysed are from our own group or from scientific collaborations of our group with other institutions. Upon request, we may also do analysis for other people, depending on the current sample load. For organic samples, we require the samples to be milled and packed in tin capsules before sending them to us. Students are encouraged to come to our lab to prepare the samples and see how the analysis runs.

We have stable-isotope mass-spectrometers and dedicated periphery to do the following routine analysis:
Organic samples 13C/12C 18O/16O 15N/14N  
Water   18O/16O   D/H
CO2 13C/12C 18O/16O    
CO 13C/12C 18O/16O    
CH4 13C/12C      

Preparation of organic samples

Mill the samples to a fine powder (no fibers should be visible). We recommend using a ball mill (works for leaves, soil, etc.) or a centrifugal mill (for wood). See e.g. the mills produced by Retsch

Samples should be packed in tin capsules for C and N and silver capsules for O. The necessary amount depends on the isotope to be analysed and the carbon, oxygen or nitrogen content. For leaf samples or materials with similar elemental composition, the following amounts should be packed using a micro-balance:
  • 13C/12C: 0.6-0.8 mg
  • 18O/16O: 1.0-1.2 mg
  • 15N/14N: 4.0-4.5 mg


In the past years we analyzed ecosystem carbon and water fluxes in three major projects, the Swiss Canopy Crane Project (SCC) (Effects of elevated CO2 on a mature mixed forest ecosystem), the CARBOMONT project (Effects of Land-use Changes on Sources, Sinks and Fluxes of Carbon in European Mountain Areas), and the COST-Action 627 (Effects of Elevated CO2 and N on Carbon Uptake, Allocation, Respiration and Sequestration in Grass/Clover Mixtures in a FACE Study). We have applied the tree-ring stable isotope approach in multiple studies covering sites in Switzerland, northern Eurasia and Siberia. With the EU-Project ISONET (2002-2005), and established two 400-year long C and O isotope chronologies from living trees. A continuation of this effort was funded by the completed EU-project (MILLENNIUM 2005-2010) with a 1000 year chronology in the Lötschental, Switzerland). In ecosystems of particular sensitivity to global change, we studied C and O isotopes from the last 100 years along a high-latitude transect in northern Eurasia, from Norway to Siberia. For the same period a strong increase in the water-use efficiency as a response to the increasing CO2-concentrations in the atmosphere was found since the last 100 years. In an ongoing research collaboration time series from various periods (Medieval to modern times) and durations are under investigation with the Forest Research Institutes Kransnojarsk, Ekaterinburg, and WSL Birmensdorf.

Recently, we have analysed the tree response to elevated CO2 at the timberline COST-alpin-carbon. In current projects we investigate the long-term variability in tree growth in order to understand physiological responses to environmental conditions and improve carbon cycle models (SNF-iTREE). We study the relationship between stable isotopes, water-use efficiency and tree mortality under drought (COST drought). We use the compound-specific isotope analysis of carbohydrates to understand postphotosynthetic isotope fractionations and their relationship to environmental changes on the seasonal scale, e.g. in studies in Siberia SNF Siberia.

New Project: ISOLAS

Recent results

We constructed a 1200-year drought-sensitive, well-replicated carbon isotope chronology based on historic material from buildings of the Lötschental and Simplon regions (Switzerland), combined with a chronology from living trees. Our reconstruction revealed pronounced alterations of wet and dry periods, including a long absence of wet summers during the little ice age (i.e. dry conditions) and relatively wet summers during the medieval climate anomaly (MCA).

Kress et al. (2014). Swiss tree-rings reveal warm and wet summers during medieval times. Geophysical Research Letters. DOI: 10.1002/2013GL059081

Our team

People currently working in our lab: Former researchers, guest scientists and students:

Katja Rinne, Catharina Lötscher, Maria Fischer, Olga Sidorova, Katrin Streit, Alexander Kirdyanov, Marina Bryukhanova, Michael Schmidt, Anne Kress, Christina Reynolds-Henne, Sonja Keel, Maya Jaeggi, Maria-Rosa Guerrieri, Giovanna Battipaglia, Nadine Pfahringer, Eva Bantelmann, Anastasya Knorre, Daniel Theis

Recent Publications

  • Water-use efficiency and transpiration across European forests during the Anthropocene. D. C. Frank, B. Poulter, M. Saurer, J. Esper, C. Huntingford, G. Helle, K. Treydte, N. E. Zimmermann, G. H. Schleser, A. Ahlstrom, P. Ciais, P. Friedlingstein, S. Levis, M. Lomas, S. Sitch, N. Viovy, L. Andreu-Hayles, Z. Bednarz, F. Berninger, T. Boettger, C. M. D/`Alessandro, V. Daux, M. Filot, M. Grabner, E. Gutierrez, M. Haupt, E. Hilasvuori, H. Jungner, M. Kalela-Brundin, M. Krapiec, M. Leuenberger, N. J. Loader, H. Marah, V. Masson-Delmotte, A. Pazdur, S. Pawelczyk, M. Pierre, O. Planells, R. Pukiene, C. E. Reynolds-Henne, K. T. Rinne, A. Saracino, E. Sonninen, M. Stievenard, V. R. Switsur, M. Szczepanek, E. Szychowska-Krapiec, L. Todaro, J. S. Waterhouse, M. Weigl. Nature Clim. Change advance online publication, (2015). DOI: 10.1038/nclimate2614
  • Isotope ratio mass spectrometry as a tool for source inference in forensic science: A critical review. Natacha Gentile, Rolf T. W. Siegwolf, Pierre Esseiva, Sean Doyle, Kurt Zollinger, Olivier Delémont. Forensic Science International 251, 139-158 (2015). DOI:
  • Multi-isotope labelling of organic matter by diffusion of 2H/18O-H2O vapour and 13C-CO2 into the leaves and its distribution within the plant. M. S. Studer, R. T. W. Siegwolf, M. Leuenberger, S. Abiven. Biogeosciences 12, 1865-1879 (2015). DOI: 10.5194/bg-12-1865-2015
  • Drought impact on water use efficiency and intra-annual density fluctuations in Erica arborea on Elba (Italy). Giovanna Battipaglia, Veronica De Micco, Willi A. Brand, Matthias Saurer, Giovanna Aronne, Petra Linke, Paolo Cherubini. Plant, Cell & Environment 37, 382-391 (2014). DOI: 10.1111/pce.12160
  • Increasing relevance of spring temperatures for Norway spruce trees in Davos, Switzerland, after the 1950s. Olga V. Churakova, Werner Eugster, Sebastian Zielis, Paolo Cherubini, Sophia Etzold, Matthias Saurer, Rolf Siegwolf, Nina Buchmann. Trees 28, 183-191 (2014). DOI: 10.1007/s00468-013-0941-6
  • A cluster of stratospheric volcanic eruptions in the AD 530s recorded in Siberian tree rings. Olga V. Churakova, Marina V. Bryukhanova, Matthias Saurer, Tatjana Boettger, Mukhtar M. Naurzbaev, Vladimir S. Myglan, Eugene A. Vaganov, Malcolm K. Hughes, Rolf T. W. Siegwolf. Global and Planetary Change 122, 140-150 (2014). DOI:
  • Carbon isotope discrimination during branch photosynthesis of Fagus sylvatica: a Bayesian modelling approach. Lydia Gentsch, Albin Hammerle, Patrick Sturm, Jérôme Ogée, Lisa Wingate, Rolf Siegwolf, Peter Plüss, Thomas Baur, Nina Buchmann, Alexander Knohl. Plant, Cell & Environment 37, 1516-1535 (2014). DOI: 10.1111/pce.12262
  • Carbon isotope discrimination during branch photosynthesis of Fagus sylvatica: field measurements using laser spectrometry. Lydia Gentsch, Patrick Sturm, Albin Hammerle, Rolf Siegwolf, Lisa Wingate, Jérôme Ogée, Thomas Baur, Peter Plüss, Matti Barthel, Nina Buchmann, Alexander Knohl. Journal of Experimental Botany 65, 1481-1496 (2014). DOI: 10.1093/jxb/eru024
  • Drought response of mesophyll conductance in forest understory species – impacts on water-use efficiency and interactions with leaf water movement. Robert Hommel, Rolf Siegwolf, Matthias Saurer, Graham D. Farquhar, Zachary Kayler, Juan Pedro Ferrio, Arthur Gessler. Physiologia Plantarum 152, 98-114 (2014). DOI: 10.1111/ppl.12160
  • Douglas-Fir Seedlings Exhibit Metabolic Responses to Increased Temperature and Atmospheric Drought. Kirstin Jansen, Baoguo Du, Zachary Kayler, Rolf Siegwolf, Ingo Ensminger, Heinz Rennenberg, Bernd Kammerer, Carsten Jaeger, Marcus Schaub, Jürgen Kreuzwieser, Arthur Gessler. PLoS ONE 9, e114165 (2014). DOI: 10.1371/journal.pone.0114165
  • Climate sensitivity and parameter coherency in annually resolved δ13C and δ18O from Pinus uncinata tree-ring data in the Spanish Pyrenees. Oliver Konter, Steffen Holzkämper, Gerhard Helle, Ulf Büntgen, Matthias Saurer, Jan Esper. Chemical Geology 377, 12-19 (2014). DOI:
  • Swiss tree rings reveal warm and wet summers during medieval times. Anne Kress, Sarah Hangartner, Harald Bugmann, Ulf Büntgen, David C. Frank, Markus Leuenberger, Rolf T. W. Siegwolf, Matthias Saurer. Geophysical Research Letters 41, 2013GL059081 (2014). DOI: 10.1002/2013GL059081
  • First detection of glacial meltwater signature in tree-ring δ18O: Reconstructing past major glacier runoff events at Lago Verde (Miage Glacier, Italy). Giovanni Leonelli, Manuela Pelfini, Giovanna Battipaglia, Matthias Saurer, Rolf T. W. Siegwolf, Paolo Cherubini. Boreas 43, 600-607 (2014). DOI: 10.1111/bor.12055
  • Increased water-use efficiency does not lead to enhanced tree growth under xeric and mesic conditions. Mathieu Lévesque, Rolf Siegwolf, Matthias Saurer, Britta Eilmann, Andreas Rigling. New Phytologist 203, 94-109 (2014). DOI: 10.1111/nph.12772
  • Long-term 13C labeling provides evidence for temporal and spatial carbon allocation patterns in mature Picea abies. Manuel Mildner, Martin K F Bader, Sebastian Leuzinger, Rolf T W Siegwolf, Christian Körner. Oecologia 175, 747-762 (2014). DOI: 10.1007/s00442-014-2935-5
  • Spatial variability and temporal trends in water-use efficiency of European forests. Matthias Saurer, Renato Spahni, David C. Frank, Fortunat Joos, Markus Leuenberger, Neil J. Loader, Danny McCarroll, Mary Gagen, Ben Poulter, Rolf T. W. Siegwolf, Laia Andreu-Hayles, Tatjana Boettger, Isabel Dorado Liñán, Ian J. Fairchild, Michael Friedrich, Emilia Gutierrez, Marika Haupt, Emmi Hilasvuori, Ingo Heinrich, Gerd Helle, Håkan Grudd, Risto Jalkanen, Tom Levanič, Hans W. Linderholm, Iain Robertson, Eloni Sonninen, Kerstin Treydte, John S. Waterhouse, Ewan J. Woodley, Peter M. Wynn, Giles H. F. Young. Global Change Biology 20, 3700-3712 (2014). DOI: 10.1111/gcb.12717
  • Soil warming alters microbial substrate use in alpine soils. Kathrin Streit, Frank Hagedorn, David Hiltbrunner, Magdalena Portmann, Matthias Saurer, Nina Buchmann, Birgit Wild, Andreas Richter, Sonja Wipf, Rolf T. W. Siegwolf. Global Change Biology 20, 1327-1338 (2014). DOI: 10.1111/gcb.12396
  • Lack of photosynthetic or stomatal regulation after 9 years of elevated [CO2] and 4 years of soil warming in two conifer species at the alpine treeline. Kathrin Streit, Rolf T. W. Siegwolf, Frank Hagedorn, Marcus Schaub, Nina Buchmann. Plant, Cell & Environment 37, 315-326 (2014). DOI: 10.1111/pce.12197
  • Carbon transfer, partitioning and residence time in the plant-soil system: a comparison of two 13CO2 labelling techniques. M. S. Studer, R. T. W. Siegwolf, S. Abiven. Biogeosciences 11, 1637-1648 (2014). DOI: 10.5194/bg-11-1637-2014
  • The mobility of nitrogen across tree-rings of Norway spruce (Picea abies L.) and the effect of extraction method on tree-ring δ15N and δ13C values. G. Tomlinson, R. T. W. Siegwolf, N. Buchmann, P. Schleppi, P. Waldner, P. Weber. Rapid Communications in Mass Spectrometry 28, 1258-1264 (2014). DOI: 10.1002/rcm.6897
  • Seasonal transfer of oxygen isotopes from precipitation and soil to the tree ring: source water versus needle water enrichmentKerstin Treydte, Sonja Boda, Elisabeth Graf Pannatier, Patrick Fonti, David Frank, Bastian Ullrich, Matthias Saurer, Rolf Siegwolf, Giovanna Battipaglia, Willy Werner, Arthur Gessler. New Phytologist 202, 772-783 (2014). DOI: 10.1111/nph.12741
  • Central European hardwood trees in a high-CO2 future: synthesis of an 8-year forest canopy CO2 enrichment project. Martin K. F. Bader, Sebastian Leuzinger, Sonja G. Keel, Rolf T. W. Siegwolf, Frank Hagedorn, Patrick Schleppi, Christian Körner. Journal of Ecology 101, 1509-1519 (2013). DOI: 10.1111/1365-2745.12149
  • Responses of belowground carbon allocation dynamics to extended shading in mountain grassland. Michael Bahn, Fernando A. Lattanzi, Roland Hasibeder, Birgit Wild, Marianne Koranda, Valentina Danese, Nicolas Brüggemann, Michael Schmitt, Rolf Siegwolf, Andreas Richter. New Phytologist 198, 116-126 (2013). DOI: 10.1111/nph.12138
  • Elevated CO2 increases tree-level intrinsic water use efficiency: insights from carbon and oxygen isotope analyses in tree rings across three forest FACE sites. Giovanna Battipaglia, Matthias Saurer, Paolo Cherubini, Carlo Calfapietra, Heather R. McCarthy, Richard J. Norby, M. Francesca Cotrufo. New Phytologist 197, 544-554 (2013). DOI: 10.1111/nph.12044
  • δ15N measurement of organic and inorganic substances by EA-IRMS: a speciation-dependent procedure. Natacha Gentile, Michel J. Rossi, Olivier Delémont, Rolf T. W. Siegwolf. Analytical and Bioanalytical Chemistry 405, 159-176 (2013). DOI: 10.1007/s00216-012-6471-z
  • Nine years of CO2 enrichment at the alpine treeline stimulates soil respiration but does not alter soil microbial communities. Frank Hagedorn, David Hiltbrunner, Kathrin Streit, Alf Ekblad, Björn Lindahl, Anja Miltner, Beat Frey, I. Tanya Handa, Stephan Hättenschwiler. Soil Biology and Biochemistry 57, 390-400 (2013). DOI: 10.1016/j.soilbio.2012.10.001
  • Fruit production in three masting tree species does not rely on stored carbon reserves. Günter Hoch, Rolf T. W. Siegwolf, Sonja G. Keel, Christian Körner, Qingmin Han. Oecologia , 1-10 (2013). DOI: 10.1007/s00442-012-2579-2
  • Nitrogen partitioning in oak leaves depends on species, provenance, climate conditions and soil type. B. Hu, J. Simon, T. M. Kuster, M. Arend, R. Siegwolf, H. Rennenberg. Plant Biology 15, 198-209 (2013). DOI: 10.1111/j.1438-8677.2012.00658.x
  • Is the 20th century warming unprecedented in the Siberian north? Olga V. Sidorova, Matthias Saurer, Andrei Andreev, Diedrich Fritzsche, Thomas Opel, Mukhtar M. Naurzbaev, Rolf Siegwolf. Quaternary Science Reviews 73, 93-102 (2013). DOI: 10.1016/j.quascirev.2013.05.015
  • The application of tree-rings and stable isotopes for reconstructions of climate conditions in the Russian Altai. O. V. Sidorova, R. T. W. Siegwolf, V. S. Myglan, D. V. Ovchinnikov, V. V. Shishov, G. Helle, N. J. Loader, M. Saurer. Climatic Change 120, 153-167 (2013). DOI: 10.1007/s10584-013-0805-5
  • Tracing fresh assimilates through Larix decidua exposed to elevated CO2 and soil warming at the alpine treeline using compound-specific stable isotope analysis. K. Streit, K. T. Rinne, F. Hagedorn, M. A. Dawes, M. Saurer, G. Hoch, R. A. Werner, N. Buchmann, R. T. W. Siegwolf. New Phytologist , (2013). DOI: 10.1111/nph.12074
  • A novel methodological approach for δ18O analysis of sugars using gas chromatography-pyrolysis-isotope ratio mass spectrometry. Michael Zech, Matthias Saurer, Mario Tuthorn, Katja Rinne, Roland A. Werner, Rolf Siegwolf, Bruno Glaser, Dieter Juchelka. Isotopes in Environmental and Health Studies 49, 492-502 (2013). DOI: 10.1080/10256016.2013.824875
further publications

  • Isogeochem Wiki Technical issues related to stable isotopes
  • Ehleringer Lab Stable Isotope Ratio Facility for Ecological Research in Utah
  • MIBA Moisture isotopes in the Atmosphere
  • GNIP Global Network for Isotopes in Precipitation
  • OIPC The online isotopes in precipitation calculator
  • Climate and Environmental Physics Bern Institute with long tradition in stable isotope analysis
Climate Tree rings