biogeochemistry; paleoclimate; methane; ice cores; polar ice cores; CH4
Bock M., Schmitt J., Beck J., Schneider R., Fischer H. (2014), Improving accuracy and precision of ice core δD(CH4) analyses using methane pre-pyrolysis and hydrogen post-pyrolysis trapping and subsequent chromatographic separation, in Atmospheric Measurement Techniques
, 7, 1999-2012.
Schmitt J., Seth B., Bock M., Fischer H. (2014), Online technique for isotope and mixing ratios of CH4, N2O, Xe and mixing ratios of organic trace gases on a single ice core sample, in Atmospheric Measurement Techniques
, 7(8), 2645-2665.
Möller L., Sowers T., Bock M., Spahni R., Behrens M., Schmitt J., Miller H., Fischer H. (2013), Independent variations of CH4 emissions and isotopic composition over the past 160,000 years, in Nature Geoscience
, 6(10), 885-890.
Schmitt J., Seth B., Bock M., Van Der Veen C., Möller L., Sapart C.J., Prokopiou M., Sowers T., Röckmann T., Fischer H. (2013), On the interference of Kr during carbon isotope analysis of methane using continuous-flow combustion-isotope ratio mass spectrometry, in Atmospheric Measurement Techniques
, 6(5), 1425-1445.
Bock M., Schmitt J., Behrens M., Möller L., Schneider R., Sapart C., Fischer H. (2010), A gas chromatography/pyrolysis/isotope ratio mass spectrometry system for high-precision δD measurements of atmospheric methane extracted from ice cores, in Rapid Communications in Mass Spectrometry
, 24(5), 621-633.
Bock M., Schmitt J., Möller L., Spahni R., Blunier T., Fischer H. (2010), Hydrogen isotopes preclude marine hydrate CH4 emissions at the onset of dansgaard-oeschger events, in Science
, 328(5986), 1686-1689.
Air enclosures in polar ice cores represent the only direct archive of the paleoatmosphere. Investigations on polar ice cores revealed that the atmospheric CH4 concentration was subject to substantial variations during the last glacial cycles. The sources of these CH4 changes and their feedback on (rapid) climate changes, however, are not yet unambiguously constrained. Especially, the potential role of a sudden release of large amounts of CH4 from marine gas hydrates in parallel to rapid warmings remains elusive. The scientific objective is, therefore, a differentiation of the contributions of different CH4 sources to the paleoatmospheric CH4 changes using the carbon and hydrogen isotopic signature of CH4 in polar ice cores. Due to the strong sample constraints in ice core research such isotopic measurements can only be performed by novel gas chromatography - isotope ratio mass spectrometry methods. Accordingly, within the new professorship for experimental climate and environmental physics at the University of Bern, a mass spectrometric method for d13CH4 and dD(CH4) will be established, which has been previously developed during my work at the Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven (AWI). To this end the University of Bern will pay for the acquisition of two new designated mass spectrometers (about 430,000 CHF). The cost for the set up of two peripheries (own development) required for the extraction and pretreatment of CH4 from ice samples for the d13CH4 and dD(CH4) analysis, respectively, are requested within this R’Equip proposal.