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User:Benjah-bmm27/degree/2/RPE

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Geochemistry, RPE

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"Origin and Fate of Organic Matter in the Geosphere"

formula CH4 CH3OH HCHO HCO2H CO2
molecule methane methanol formaldehyde formic acid carbon dioxide
C-O bonds 0 1 2 3 4
      • High affinity (low capacity) methanotrophs - live in well aerated soils (upland, forests, grasslands, farmland), adapted to [CH4] up to 12 ppm
      • Investigate high affinity methanotrophs by following their characteristic PFLAs. Analyse 13CH4-fed methanotroph colonies for 13C-rich PFLAs to find out which PFLAs are characteristic.
      • Methanotrophs cannot do their job if their habitats are destroyed - woodland → agricultural land means [N] ↑ so methanotrophs inhibited
      • Need to use land correctly to protect methanotrophs and allow them to help prevent [CH4] ↑
  • Biochemicals:
  • C3 and C4 plants:
  • Bengal fan - an alluvial fan: may be contaminated, but very good temporal resolution. Palaesol and ocean sediment carbon isotope records match and suggest a shift from C3 to C4, starting 9 Ma, peaking 4 Ma, and now returning towards C3 values.
  • Paleosols: in situ, so less contamination, but poor temporal resolution because mixing occurs
  • Biomarkers of terrestrial vegetation, e.g. C27, C29, C31, C33 n-alkanes