Publications (full list below)

Featured publication

K. Lenhart, B. Weber, W. Elbert, J. Steinkamp, T. Clough, P. Crutzen, U. Pöschl, F. Keppler (2015). Nitrous oxide and methane emissions from cryptogamic covers. Global Change Biology, doi: 10.1111/gcb.12995

​Cryptogamic covers, which comprise some of the oldest forms of terrestrial life on Earth (Lenton & Huntingford, 2003), have recently been found to fix large amounts of nitrogen and carbon dioxide from the atmosphere (Elbert et al., 2012). Here we show that they are also greenhouse gas sources with large nitrous oxide (N2O) and small methane (CH4) emissions. Whilst N2O emission rates varied with temperature, humidity, and N deposition, an almost constant ratio with respect to respiratory CO2 emissions was observed for numerous lichens and bryophytes. We employed this ratio together with respiration data to calculate global and regional N2O emissions. If our laboratory measurements are typical for lichens and bryophytes living on ground and plant surfaces and scaled on a global basis, we estimate a N2O source strength of 0.32–0.59 Tg year-1 for the global N2O emissions from cryptogamic covers. Thus, our emission estimate might account for 4–9% of the global N2O budget from natural terrestrial sources. In a wide range of arid and forested regions, cryptogamic covers appear to be the dominant source of N2O. We suggest that greenhouse gas emissions associated with this source might increase in the course of global change due to higher temperatures and enhanced nitrogen deposition.

Figure Flux Scheme
Figure 4 Tmp2x2 230114

Full list

Peer reviewed papers - group members including former members are shown in bold


  • K. Benzing, P. Comba, B. Martin, B. Pokrandt, F. Keppler (2017). Nonheme iron-oxo-catalyzed methane formation from methyl-thioethers: Scope, mechanism and relevance for natural systems. Chemistry - A European Journal, 23, 10465 – 10472.

  • F. Keppler, J. Fischer, T. Sattler, D. Polag, N. Jaeger, H. F. Schöler, M. Greule (2017). Chloromethane emissions in human breath. Science of the Total Environment, 605, 405-410.

  • C. Mayer, U. Schreiber, O. Schmitz, P. Rosendahl, A. Bronja, M. Greule, F. Keppler, I. Mulder, T. Sattler, H.F. Schöler (2017). Organic compounds in fluid inclusions of Archean quartz - archives of prebiotic chemistry on early Earth. PlosOne, 12, e0177570.

  • K. Geisler, M. Greule, U. Schäfer, J. Hans, T. Geisler, L. Meier, F. Keppler, G. Krammer (2017). Vanilla authenticity control by DNA barcoding and isotope data aggregation. Flavour and Fragrance Journal, 32, 228-237.

  • J. Hepp, R. Zech, K. Rozanski, M. Tuthorn, B. Glaser, M. Greule, F. Keppler, Y. Huang, W. Zech, M. Zech (2017). Late Quaternary relative humidity changes from Mt. Kilimanjaro, based on a biomarker-isotope paleohygrometer. Quaternary International, 438, Part B, 116-130.

  • T. Anhäuser, M. Greule, F. Keppler (2017) Stable hydrogen isotope values of lignin methoxyl groups of four tree species across Germany and their implication for temperature reconstruction Science of The Total Environment, 579, 263-271.
  • T. Anhäuser, M. Greule, D. Polag , G.J. Bowen, F. Keppler (2017) Mean annual temperatures of mid-latitude regions derived from δ²H values of wood lignin methoxyl groups and its implications for paleoclimate studies. Science of The Total Environment, 574, 1276-1282.


  • K.A. Kamilli, J. Ofner, T. Krause, T. Sattler, P. Schmitt-Kopplin, E. Eitenberger, G. Friedbacher, B. Lendl, H. Lohninger, H.F. Schöler, A. Held (2016) How salt lakes affect atmospheric new particle formation: A case study in Western Australia. Science of The Total Environment, 573, 985-995.
  • J. Hepp, M. Rabus, T. Anhäuser, T. Bromm , C. Laforsch, F. Sirocko, B. Glaser, M. Zech (2016) A sugar biomarker proxy for assessing terrestrial versus aquatic sedimentary input. Organic Geochemistry, 98, 98-104.
  • K. Lenhart, T. Klintzsch, G. Langer, G. Nehrke, M. Bunge, S. Schnell, F. Keppler (2016) Evidence for methane production by the marine algae Emiliania huxleyi, Biogeosciences. 13, 3163-3174.
  • F. Keppler, A. Schiller, R. Ehehalt, M. Greule, J. Hartmann, D. Polag (2016) Stable isotope and high precision concentration measurements confirm that all humans produce and exhale methane. J. Breath Res. 10, 16003.
  • D. Riechelmann, M. Greule, K.S. Treydte, J. Esper and F. Keppler (2016) Climate signals in δ13C of wood lignin methoxyl groups from high elevation larch trees. Palaeogeogr. Palaeoclimatol. Palaeoecol. 445, 60–71.


  • D. Polag, T. May, L. Müller, H. König, F. Jacobi, S. Laukenmann, F. Keppler (2015). Online monitoring of stable carbon isotopes of methane in anaerobic digestion as a new tool for early warning of process instability. Bioresource Technology, doi:10.1016/j.biortech.2015.08.058

  • K. Lenhart, B. Weber, W. Elbert, J. Steinkamp, T. Clough, P. Crutzen, U. Pöschl, F. Keppler (2015). Nitrous oxide and methane emissions from cryptogamic covers. Global Change Biology, doi: 10.1111/gcb.12995

  • T. May, M. Koch-Singenstreua, J. Ebling, R. Stantscheff, L. Müller, F. Jacobi, D. Polag, F. Keppler, H. König (2015). Design and application of a synthetic DNA standard for real-time PCR analysis of microbial communities in a biogas digester. Applied Microbiology and Biotechnology, doi: 10.1007/s00253-015-6721-z

  • C. McRoberts, F. Keppler, D.B. Harper, J.T.G. Hamilton (2015). Seasonal changes in chlorine and methoxyl content of leaves of deciduous trees and their impact on release of chloromethane and methanol at elevated temperatures. Environmental Chemistry, doi: 10.1071/EN14208. 

  • M. Greule, A. Mosandl, J.T.G. Hamilton, F. Keppler (2015). Comment on: “Authenticity and Traceability of Vanilla Flavors by Analysis of Stable Isotopes of Carbon and Hydrogen”. Journal of Agricultural and Food Chemistry,  63, 5305–5306.

  • M. Mischel, J. Esper, F. KepplerM. Greule, W. Werner (2015). δ2H, δ13C and δ18O from whole wood, α-cellulose and lignin methoxyl groups in Pinus sylvestris: a multi-parameter approach. Isotopes in Environmental and Health Studies , doi: 10.1080/10256016.2015.1056181.

  • ​K. Lenhart, F. Althoff, M. Greule, F. Keppler (2015) Technical Note: Methionine, a precursor of methane in living plants. Biogeosciences 12, 1907-1914

  • T. Anhäuser, M. Greule, M. Zech, Kalbitz, K., C. McRoberts, F. Keppler (2015) Stable hydrogen and carbon isotope ratios of methoxyl groups during plant litter degradation. Isotopes in Environmental and Health Studies 51, 143-154,
  • M. Greule, A. Rossmann, H.-L. Schmidt, A. Mosandl and F. Keppler (2015) A Stable Isotope Approach to Assessing Water Loss in Fruits and Vegetables during Storage. J. Agric. Food Chem., 63, 1974-1981. Available at:


  • T. Nadalig, M. Greule, Francoise Bringel, F. Keppler, S. Vuilleumier (2014). Probing the diversity of chloromethane-degrading bacteria by comparative genomics and isotopic fractionation. Frontiers in Microbiology, 5, 523, doi: 10.3389/fmicb.2014.00523.
  • F. Keppler, D.B. Harper, M. Greule, U. Ott, T. Sattler, H.F. Schöler, J.T.G. Hamilton (2014). Chloromethane release from carbonaceous meteorite affords new insight into Mars lander findings. Scientific Reports, 4, 7010; DOI:10.1038/srep07010.
  • T. Anhäuser, F. Sirocko, M. Greule, J. Esper, F. Keppler (2014). D/H ratios of methoxyl groups of the sedimentary organic matter of Lake Holzmaar (Eifel, Germany): a potential palaeoclimate/-hydrology proxy. Geochimica et Cosmochimica Acta, 142, 39-52, doi: 10.1016/j.gca.2014.08.001.
  • F. Althoff, K. Benzing, P. Comba.,C. McRoberts, D.R. Boyd, S. Greiner, F. Keppler (2014). Abiotic methanogenesis from organosulfur compounds under ambient conditions. Nature Communications, 5, 4205, doi: 10.1038/ncomms5205.
  • D. Polag, O. Leiß, F. Keppler (2014). Age dependent breath methane in the German population. Science of the Total Environment, 481, 582-587.
  • D. Polag, L.C. Krapf, S. Laukenmann, H. Heuwinkel, J. Lelieveld, F. Keppler (2014). Stable carbon isotopes of methane for real-time process monitoring in anaerobic digesters. Engineering in Life Sciences, 4, 153-160.
  • A. Horst, H. Holmstrand, P. Andersson, B.F. Thornton, A. Wishkerman, F. Keppler, Ö. Gustafsson (2014). Stable bromine isotopic composition of methyl bromide released from plant matter. Geochimica et Cosmochimica Acta, 125, 186-195.


  • T. Nadalig, M. Greule, Francoise Bringel, S. Vuilleumier, F. Keppler (2013). Hydrogen and carbon isotope fractionation during degradation of chloromethane by methylotrophic bacteria. MicrobiologyOpen, doi: 10.1002/mbo3.124.

  • D. Polag, S. Laukenmann, H. Heuwinkel, M. Greule, F. Keppler (2013). Evidence of anaerobic syntrophic acetate oxidation in biogas batch reactors using stable carbon isotopes labelling experiments. Isotopes in Environmental and Health Studies, 49, 365-77.
  • O. Wuerfel, M. Greule, F. Keppler, M.A. Jochmann, T.C. Schmidt (2013). Position Specific Isotope Analysis of the Methyl Group Carbon in Methylcobalamin for the Investigation of Biomethylation Processes. Analytical and Bioanalytical Chemistry, 405, 2833-2841.
  • Y. Gori, R. Wehrens, M. Greule, F. Keppler, L. Ziller, N. La Porta, F. Camin (2013). C, H and O stable isotope ratios of whole wood, cellulose and lignin methoxyl groups of Picea abies as climatic proxy. Rapid Communication in Mass Spectrometry, 27, 265-275.


  • M. Greule, S.G. Huber, F. Keppler (2012). Stable hydrogen-isotope analysis of methyl chloride emitted from halophytic plants. Atmospheric Environment, 62, 584-592.

  • K. Lenhart, M. Bunge, S.Rathering, T. Neu, I. Schüttman, M. Greule, C. Kammann, S. Schnell, C. Müller, H. Zorn, F. Keppler (2012). Evidence for methane production by saprotrophic fungi. Nature Communications, 3, 1046, doi:10.1038/ncomms2049.

  • F. Keppler, I. Vigano, A. McLeod, U. Ott, M. Früchtl, T. Röckmann (2012). Ultraviolet-radiation-induced methane emissions from meteorites and the Martian atmosphere. Nature, 486, 93-96.

  • M. Hurkuck, F. Althoff, H. Jungkunst, A. Jugold, F. Keppler (2012). Release of methane from aerobic soil: an indication of a novel chemical natural process? Chemosphere, 86, 684-689.

  • L. Derendorp, A. Wishkerman, F. Keppler, C. McRoberts, R. Holzinger, T. Röckmann (2012). Methyl chloride emissions from halophyte leaf litter: dependence on temperature and chlorine content. Chemosphere, 87, 483-489.


  • M. Greule, F. Keppler (2011). Stable isotope determination of ester and ether methyl moieties in plant methoxyl groups. Isotopes in Environmental and Health Studies, 47, 470-482.
  • Z.-P. Wang, F. Keppler, M. Greule, J.T.G. Hamilton (2011). Non-microbial methane emissions from fresh leaves: effects of physical wounding and anoxia. Atmospheric Environment 45, 4915-4921.
  • L. Derendorp, R. Holzinger, A. Wishkerman, F. Keppler, T. Röckmann (2011). Methyl chloride and C2–C5 hydrocarbon emissions from dry leaf litter and their dependence on temperature. Atmospheric Environment, 45, 3112-3119.
  • A. Wishkerman, S. Greiner, M. Ghyczy, M. Boros, T. Rausch, K. Lenhart, F. Keppler (2011). Enhanced formation of methane in plant cell cultures by inhibition of cytochrome c oxidase. Plant Cell & Environment, 34, 457–464.


  • S. Laukenmann, D. Polag, H. Heuwinkel, M. Greule, A. Gronauer, J. Lelieveld, F. Keppler (2010). Identification of methanogenic pathways in anaerobic digesters using stable carbon isotopes. Engineering in Life Sciences, 10, 509–514.

  • M. Greule, L. D. Tumino, T. Kronewald, U. Hener, J. Schleucher, A. Mosandl, F. Keppler (2010). Improved rapid authentication of vanillin using δ13C and δ2H values. European Food Research Technology, 231, 933–941.

  • T. Röckmann, C.X. Gómez Álvarez, S. Walter, C. van der Veen, A.G. Wollny, S. Gunthe, G. Helas, U. Pöschl, F. Keppler, M. Greule, W.A. Brand (2010). The isotopic composition of H2 from biomass burning - dependency on combustion efficiency, moisture content and dD of local precipitation. Journal of Geophysical Research, 115, D17308, doi:10.1029/2009JD013188.

  • F. Keppler, S. Laukenmann, J. Rinne, H. Heuwinkel, M. Greule, M. Whiticar, J. Lelieveld (2010). Measurements of 13C/12C Methane from Anaerobic Digesters: Comparison of Optical Spectrometry with Continuous-Flow Isotope Ratio Mass Spectrometry. Environmental Science & Technology, 44, 5067-5073.

  • F. Althoff, A. Jugold, F. Keppler (2010). Methane Formation by Oxidation of Ascorbic Acid using Iron Minerals and Hydrogen Peroxide. Chemosphere, 80, 286-292.

  • I. Vigano, R. Holzinger, T. Röckmann, F. Keppler, M. Greule, W.A. Brand, H. Geilmann (2010). Water drives the deuterium content of the methane emitted from plants. Geochimica et Cosmochimica Acta, 74, 3865–3873.


  • F. Keppler, M. Boros, C. Frankenberg, J. Lelieveld, A. McLeod, A.M. Pirttilä, T. Röckmann, J.-P. Schnitzler (2009). Methane formation in aerobic environments. Environmental Chemistry, 6, 459-465.
  • I. Vigano, R. Holzinger, T. Röckmann, A. van Dijk, F. Keppler, M. Greule, W.A. Brand, H. Geilmann, J. van Dongen (2009). The stable isotope signature of methane emitted from plant material under UV irradiation. Atmospheric Environment, 43, 5637-5646.
  • N. Yassaa, A. Wishkerman, F. Keppler, J. Williams (2009) Fast determination of methyl chloride and methyl bromide emissions from plant matter and soil samples using HS-SPME and GC-MS. Environmental Chemistry, 6, 311-318.
  • M. Greule, A. Mosandl, J.T.G. Hamilton, F. Keppler (2009). A simple rapid method to precisely determine 13C/12C ratios of plant methoxyl groups. Rapid Communication in Mass Spectrometry, 23, 1710-1714.
  • L. Weissflog, N.F. Elanskii, K. Kotte, F. Keppler, A. Pfennigsdorff, K. Lange E. Putz, L.V. Lisitzina (2009). Late permian changes in conditions of the atmosphere and environments caused by halogenated gases. Doklady Earth Sciences, 425, 291-295.


  • F. Keppler, J.T.G. Hamilton (2008). Tracing the geographical origin of early potato tubers using stable hydrogen isotope ratios of methoxyl groups. Isotopes in Environmental and Health Studies, 44, 337-347.
  • M. Greule, A. Mosandl, J.T.G. Hamilton, F. Keppler (2008). A rapid and precise method for determination of D/H ratios of plant methoxyl groups Rapid Communication in Mass Spectrometry, 22, 3983-3988.
  • A. Wishkerman, S. Gebhardt, C.W. McRoberts, J.T.G. Hamilton, J. Williams, F. Keppler (2008). Abiotic methyl bromide formation from vegetation and its strong dependence on temperature Environmental Science & Technology, 42, 6837-6842.
  • I. Vigano, R. Holzinger, H. van Weelden, F. Keppler, A. McLeod, T. Röckmann (2008). Effect of UV radiation and temperature on the emission of methane from plant biomass and structural components. Biogeosciences, 5, 937-947.
  • F. Keppler, J.T.G. Hamilton, C.W. McRoberts, I. Vigano, M. Braß, T. Röckmann (2008). Methoxyl groups of plant pectin as a precursor compound for atmospheric methane: evidence from deuterium labelling studies. New Phytologist, 178, 808-814.
  • S. Draxler, F. Keppler (2008). Ansätze zur regionalen Quantifizierung von Methan aus Pflanzen. UWSF – Z Umweltchem Ökotox, 20(1) 75-79.


  • G. Rösing, F. Keppler (2007). Production of biogas. PCT Int. Appl., WO 2006-EP7504, 32 pp.
  • F. Keppler, D.B. Harper, R.M. Kalin, W. Meier-Augenstein, N. Farmer, S. Davis, H.-L. Schmidt, D.M. Brown, J.T.G Hamilton (2007). D/H ratios of lignin methoxyl groups as a paleoclimate proxy and constraint of the geographical origin of woods. New Phytologist, 176, 600-609.


  • F. Keppler, R. Borchers, J.T.G. Hamilton, G. Kilian, J. Pracht, H. F. Schöler, (2006). De-novo formation of chloroethyne in soil. Environmental Science & Technology 40, 130-134.
  • F. Keppler, J.T.G. Hamilton, M. Brass, T. Röckmann (2006). Methane emissions from terrestrial plants under aerobic conditions. Nature, 439, 187-191.
  • S. Houweling, T. Röckmann, I. Aben, F. Keppler, M. Krol, J.-F. Meirink, E. J. Dlugokencky, C. Frankenberg (2006). Atmospheric constraints on global emissions of methane from plants. Geophysical Research Letters, 33, L15821, doi:10.1029/2006GL026162.


  • F. Keppler, T. Röckmann, R.M. Moore, D.B. Harper, J.T.G. Hamilton (2005). New insight into the atmospheric chloromethane budget gained using stable carbon isotope ratios. Atmospheric Chemistry and Physics 5, 2403-2411.


  • F. Keppler, R.M. Kalin, D.B. Harper, W.C. McRoberts, J.T.G. Hamilton (2004). Carbon isotope anomaly in the major plant C1 pool and its global biogeochemical implications. Biogeosciences 1, 123-131.
  • H. Biester, F. Keppler, A. Putschew, A. Martinez-Cortizas, M. Petri (2004). Halogen retention, organohalogens and the role of organic matter decomposition on halogen enrichment in two Chilean peat bogs. Environmental Science & Technology 38, 1984-1991, DOI: 10.1021/es0348492.
  • F. Keppler, H. Biester, A. Putschew, P. J. Silk, H.F. Schöler, G. Müller (2004). Organoiodine formation during humification in peatlands: a key process in terrestrial iodine cycling. Environmental Chemistry Letters 1, 219-223, DOI: 10.1007/s10311-003-0044-5.


  • J.T.G. Hamilton, W.C. McRoberts, F. Keppler, R.M. Kalin, D.B. Harper (2003). Chloride methylation by plant pectin: an efficient environmentally significant process. Science 301, 206-209.
  • F. Keppler and H. Biester (2003). Peatlands: a major sink of naturally formed organic chlorine. Chemosphere 52, 451-453.
  • H. F. Schöler, F. Keppler, I. J, Fahimi, V. W. Niedan (2003). Fluxes of trichloroacetic acid between atmosphere, biota, soil and groundwater. Chemosphere 52, 339-354.
  • I. Fahimi, F. Keppler, H.F. Schöler (2003). Formation of chlorinated acetic acids from soil, humic acid and phenolic moieties. Chemosphere 52, 513-520.
  • H.F. Schöler and F. Keppler (2003). Abiotic formation of organohalogens in the terrestrial environment. Chimia, 57(1/2), 33-34.
  • F. Keppler, R. Borchers, P. Elsner, I. Fahimi, J. Pracht, H. F. Schöler (2003). Formation of volatile iodinated organic compounds in soil – results from laboratory studies. Chemosphere 52, 477-483.
  • A. Putschew, F. Keppler, M. Jekel (2003). Differentiation of the halogen content of peat samples using ion chromatography after combustion (TX/TOX-IC). Analytical and Bioanalytical Chemistry, 375, 781-785.
  • V.W. Niedan, F. Keppler, B. Ahlsdorf, H.F. Schöler (2003). Anthropogenically induced de-novo formation of organochlorines. Biogeochemistry 62, 277-287.

2002 - 1998

  • F. Keppler, R. Borchers, J. Pracht, S. Rheinberger, H. F. Schöler (2002). Natural formation of vinyl chloride in the terrestrial environment. Environmental Science & Technology 36, 2479-2483.
  • J. Pracht, J. Boenigk, M. Isenbeck-Schröter, F. Keppler, H.F. Schöler (2001). Abiotic Fe(III) induced mineralization of phenolic substances. Chemosphere 44, 613-619.
  • F. Keppler, R. Eiden, V.W. Niedan, J. Pracht, H.F. Schöler (2000). Halocarbons as degradation products of organic matter by natural oxidation processes.​ Nature 403, 298-301.
  • V.W. Niedan, F. Keppler, B. Ahlsdorf, H.F. Schöler (1998). Bildung von Organohalogenen in einer kommunalen Kläranlage. Vom Wasser 91, 175-184.


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