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PERGAMON Workshop CH4OX Kiel, June 6-8, 2012

PERGAMON Workshop CH4OX Kiel, June 6-8, 2012. Establishing standard protocols for the quantification of microbial methane oxidation rates in sediments and in the water column Tina Treude & Ingeborg Bussmann. Introduction. Why a workshop on methane oxidation methods?. Because….

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PERGAMON Workshop CH4OX Kiel, June 6-8, 2012

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  1. PERGAMON Workshop CH4OX Kiel, June 6-8, 2012 Establishing standard protocols for thequantification of microbial methane oxidation rates in sediments and in the water columnTina Treude & Ingeborg Bussmann

  2. Introduction Why a workshop on methane oxidation methods? Because….. …community working on methane oxidation rates is increasing. …experiences need to be exchanged. …methods should be optimized/streamlined to reach maximum comparability. PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  3. Introduction 1. Aerobic oxidation of methane by methanotrophic bacteria at the sediment-water interface or in the water column CH4 + 2O2  CO2 + 2H2O methane oxygen carbon dioxide water ΔG°= -204 kJ mol-1 2. Anaerobic oxidation of methane by methanotrophic archaea and sulfate-reducing bacteria in deeper zones of the sediment CH4 + SO42-  HCO3- + HS- + H2O methane sulfate bicarbonate sulfide water ΔG°= -16.6 kJ mol-1 PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  4. Introduction 1. Aerobic oxidation of methane by methanotrophic bacteria at the sediment-water interface or in the water column 14CH4 + 2O2 14CO2 + 2H2O methane oxygen carbon dioxide water ΔG°= -204 kJ mol-1 2. Anaerobic oxidation of methane by methanotrophic archaea and sulfate-reducing bacteria in deeper zones of the sediment 14CH4 + SO42-  H14CO3- + HS- + H2O methane sulfate bicarbonate sulfide water ΔG°= -16.6 kJ mol-1 PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  5. Introduction 1. Aerobic oxidation of methane by methanotrophic bacteria at the sediment-water interface or in the water column C3H4 + 2O2 CO2 + 23H2O methane oxygen carbon dioxide water ΔG°= -204 kJ mol-1 2. Anaerobic oxidation of methane by methanotrophic archaea and sulfate-reducing bacteria in deeper zones of the sediment 14CH4 + SO42-  H14CO3- + HS- + H2O methane sulfate bicarbonate sulfide water ΔG°= -16.6 kJ mol-1 PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  6. Introduction Final Goal of the Workshop Minimum: Method protocols published on the PERGAMON website Optimum: "Best practice" Publication PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  7. Introduction PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  8. Introduction Participants:Tina Treude (GEOMAR),Stefan Krause (GEOMAR),Philip Steeb (GEOMAR),Ingeborg Bussmann (AWI),Roman Osudar (AWI),Helge Niemann (Uni Basel),Lea Steinle (Uni Basel)Jens Kallmeyer (Uni Potsdam),Susan Mau (MPI Bremen),Anna Matousu (University of South Bohemia) PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  9. Overview Workshop Overview Presentations Treude, T.: General introduction into methods for anaerobic oxidation of methane (AOM) Bussmann, I.: General introduction into methods for aerobic oxidation of methane (MOx) Kallmeyer, J: Relevance of blanks in radiotracer measurements Mau, S: Comparison of the tracers [3H]-CH4 and [14C]-CH4 to measure methane oxidation rates in the water column PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  10. Overview Workshop Overview Discussions Discussing pros/cons and necessary improvements/streamlining of AOM rate measurements in sediments. Discussing pros/cons and necessary improvements/streamlining of MOx rate measurements in the water column. Tasks Preparation of optimized method protocols for "AOM" and "MOx". Planning of method guidelines PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  11. AOM Anaerobic oxidation of methane (AOM) PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  12. AOM • AOM in sediments(only with sulfate) • Introduction • Approaches and methodologies • Sampling equipment • Incubation • Vials/tubes • Amount of replicates (depending on vial/tube) • Tracer amounts (liquid volume and activity) • Time • Temperature, Light • How to stop • High vs. low active sediments (time, tracer) • Controls • Minimum amount • Corrections PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  13. AOM • AOM in sediments(only with sulfate) • Storage • Different types of vials • Length of storage • Analyses • GC • radioactive CH4 • radioactive CO2 • Volume determination • Scintillation counting • Calculations PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  14. AOM • AOM in sediments(only with sulfate) • Potential pitfalls and suggestions for • improvements • Degassing/loss of methane gas • Smearing • Sediment compression • Core slicing • Ex situ vs in situ • Heterogeneity (extrapolations) • Error in the vial headspace volume • Re-oxidation and loss of methane in • glass tube incubations PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  15. AOM • AOM in sediments(only with sulfate) • Data reporting • Volumetric rates vs. rates per weight • cm2 vs. m2 • Day vs. year • Replicates vs. means (and standard deviations) PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  16. MOx in thewater column Aerobic oxidation of methane (MOx) PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  17. General - methane concentrations range from 1 to 5 nM in open ocean to < 1000 nM in freshwater - rather low consumption rates, compared to the sediment - but the volume of the water column(s) is immense, thus MOXrate in the water column have to be taken into account MOx in thewater column PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  18. P E P E P E P E E E E E E E E E E E E E E E E E E E E E E E E E Principle of tracer measurements *educt = * product total educt total product MOx in the water column incubation time PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  19. MOx in thewater column PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  20. Incubation: - bottle size (20 - 160 ml) - stoppers (different materials, also toxic ones!!) - incubation time - bubble size & syringe MOx in thewater column PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  21. freshwater controls Incubation: bottle size stoppers incubation time bubble size & syringe stopping the incubation controls storage of samples MOx in the water column PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  22. Sample processing MOx in the water column PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  23. Sample processing: - immediate counting of *CH4 containing fraction - *H2O containing fraction is stable over time Sample storage - as short as possible - keep cool MOx in the water column PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  24. Calculation: - turnover time (days) = 1 / k‘ = [CH4] / rox - methane oxidation rate (nmol L-1 d-1) = k‘ / [CH4] - effective first orde rate k‘ = fraction of tracer oxidized per unit time MOx in the water column PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  25. MOx in the water column Results from off Spitzbergen 2011 PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  26. MOx in the water column Results from Elbe transects PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

  27. Thank you for your attention PERGAMON Workshop CH4OX, Kiel, June 6-8, 2012

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