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Methane cycling in contemporary and ancient peats as revealed by microbial lipid biogeochemistry
Project leader: Prof. dr. J. S. Sinninghe Damsté
Researcher(s): Dr. J. F. van Winden
Starting date: 1-jul-07

Abstract
The requested PhD student at UU will analyse contemporary and older peats for the occurrence of biomarker lipids of micro-organisms involved in the methane cycle in close collaboration with the microbiology/ecology project at the Radboud University. Both, methanogens (di- and tetraether lipids) and methanotrophs (fatty acids and functionalized biohopanoids) contain characteristic lipids which can be used. Moreover, their 13C and 14C content can be used to decipher carbon cycling in peats, especially if labeled tracers (e.g. 13C-methane) are applied in experimental mesocosm studies as described above. By monitoring the label incorporation into specific lipids of Sphagnum (triterpenoids, sterols, n-alkanes) the importance of aerobic methane oxidation for the availability of CO2 for photosynthesis by Sphagnum will be assessed. This information will be used to understand the so-called 14C reservoir effect of peat deposits (i.e. the observation that the radiocarbon age of peat deposits is older than the actual age), which complicates the use of peats as archives of past climates. Finally, biomarkers will also be used to assess ancient methane cycling in peats to unravel if environmental controls have a significant influence on the functioning of the methane cycle.

Publications
Julia F. van Winden, Nardy Kip, Gert-Jan Reichart, Mike S.M. Jetten, Huub J.M. Op den Camp, Jaap S. Sinninghe Damsté (2010). Lipids of symbiotic methane-oxidizing bacteria in peat moss studied using stable carbon isotopic labelling. Organic Geochemistry41: 1040-1044.
Darwin Center authors: op den Camp H. J. M., Jetten M. S. M., Kip D. J., Reichart G. J., Sinninghe Damsté J. S., van Winden J. F.

Brader, A.V., van Winden, J.F., Bohncke, S.J.P., Beets, C.J., Reichart, G.J., de Leeuw, J.W. (2010). Fractionation of hydrogen, oxygen and carbon isotopes in n-alkanes and cellulose of three Sphagnum species. Organic Geochemistry41: 1277-1284.
Darwin Center authors: Reichart G. J., van Winden J. F.

Nardy Kip, Julia F. van Winden, Yao Pan, Levente Bodrossy, Gert-Jan Reichart, Alfons J. P. Smolders, Mike S. M. Jetten, Jaap S. Sinninghe Damsté and Huub J. M. Op den Camp (2010). Global prevalence of methane oxidation by symbiotic bacteria in peat-moss ecosystems. Nature Geosciences3: 617-621.
Darwin Center authors: op den Camp H. J. M., Jetten M. S. M., Kip D. J., Reichart G. J., Sinninghe Damsté J. S., van Winden J. F.

Julia van Winden (2011). Methane cycling in peat bogs: Environmental relevance of methanotrophs revealed by microbial lipid chemistry.
Darwin Center authors: van Winden J. F.

Nardy Kip Wenjing Ouyang Julia van Winden Ashna Raghoebarsing Laura van Niftrik Arjan Pol Yao Pan Levente Bodrossy Elly G. van Donselaar Gert-Jan Reichart Mike S. M. Jetten Jaap S. Sinninghe Damsté and Huub J. M. Op den Camp (2011). Detection, Isolation, and Characterization of Acidophilic Methanotrophs from Sphagnum Mosses. applied and environmental microbiology77: 5643-5654.
Darwin Center authors: op den Camp H. J. M., Jetten M. S. M., Kip D. J., van Niftrik L.A.M.P., Reichart G. J., Sinninghe Damsté J. S., van Winden J. F.

van Winden, J.F., Reichart, G.J., McNamara, N.P., Benthien, A., Sinninghe Damsté, J.S. (2012). Temperature-induced increase in methane release from peat bogs: A mesocosm experiment. PloS One7:
Darwin Center authors: Reichart G. J., Sinninghe Damsté J. S., van Winden J. F.

van Winden, J.F., Talbot, H.M., De Vleeschouwer, F., Reichart, G.J., Sinninghe Damsté, J.S. (2012). Variation in methanotroph-related proxies in peat deposits from Misten Bog, Hautes-Fagnes, Belgium. Organic Geochemistry53: 73-79.
Darwin Center authors: Reichart G. J., Sinninghe Damsté J. S., van Winden J. F.