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Baupte progress meeting 8 – 10/11/04

Baupte progress meeting 8 – 10/11/04. « Earth Science Institute of Orleans », France UMR 6531 of CNRS – University of Orleans. Fatima Laggoun Laure Comont Jean-Robert Disnar Marielle Hatton. WP 05: Physical and chemical quality of peat organic matter. Objectives:.

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Baupte progress meeting 8 – 10/11/04

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  1. Baupte progressmeeting 8 – 10/11/04 « Earth Science Institute of Orleans », France UMR 6531 of CNRS – University of Orleans Fatima Laggoun Laure Comont Jean-Robert Disnar Marielle Hatton

  2. WP 05: Physical and chemical quality of peat organic matter Objectives: • Determine bulk characterictics (FTIR and C & N contents) of peat along various profiles at the different sites and their potential as indicators of peat quality. • Determine the degradation processes of peat organic matter (physical structure and biomarkers) in pristine and cut-over sites in relation to microbial communities and vegetation keystone-species. • Assess experimentaly the decomposition kinetics of plant tissues into geopolymers so as to define the most favourable conditions for long-term sequestration of C in restored peatlands.

  3. I. Bulk peat characteristics C, N contents: all WP1 samples have been completed and data analysis finished Micromorphology and organic constituent countings all WP1 samples run and preliminary data analysis performed

  4. density (g/cm3) density (g/cm3) cumulative % of org.const. cumulative % of org.const. C/N ratio C/N ratio Replicate 3 Replicate 2 FRB : 1st regeneration stage RUSSEY FRA : bare peat Regenerating peat ? • Higher density in the top of « old » peat • C/N ratios ≈ constant • Comparable organic composition, except the higher % of mucilage in FRB associated to micro-organism %.

  5. density (g/cm3) density (g/cm3) cumulative % of org.const. C/N ratio cumulative % of org.const. C/N ratio RUSSEY FRC: 2nd regeneration stage FRD : intact area ? ? Regenerat.peat? Replicate 2 Replicate 3 • Considering density, C/N, org const. evolution => limit between « old » peat and regenerat. peat ≈ 20-25cms • regenerating peat: a nice plant succession ! heterogeneous org. composition • Bulk characteristics of FRD’s OM strangely similar to that of FRC ? Except the more homogeneous composition of uppermost peat (Sph. mainly)

  6. density (g/cm3) cumulative % of org.const. C/N ratio density (g/cm3) cumulative % of org.const. C/N ratio Replicate 3 Replicate 1 BAUPTE FBB : bare peat FBA : E.angustifulium • Higher density in superficial peat levels (3 & 4) correlated (for FBA) with lower C/N ratios => higher degradation ? • FBB: homogeneous composition. • FBA: more heterogeneous with high % of AOM & microorg. • well-correlated with high C microbial biomass in level 3 (see WP06 results).

  7. density (g/cm3) density (g/cm3) cumulative % of org.const. C/N ratio cumulative % of org.const. C/N ratio Replicate 2 Replicate 3 CHAUX D’ABEL CHA : fen CHB : transitional Regenerat.peat? • CHA and CHB: similar OM properties • In CHB: better delimitation of regenerating peat • In both sites: OM of regenerating peat mainly composed of sphag. & Cyper. tissues

  8. density (g/cm3) cumulative % of org.const. C/N ratio density (g/cm3) cumulative % of org.const. C/N ratio CHAUX D’ABEL CHC : bog CHD : Intact ? ? ? Replicate 1 Replicate 1 • - however, in CHC: uppermost peat mainly composed of sphagna • the limit between « old » peat & regener. peat: not very clear • OM composition: homogeneous, except level 5: higher degradation ? • Intact zone: a lot of missing uppermost samples to conclude anything

  9. SCC: 1st regen. stage (Eriophorum) SCOTLAND SCA: bare peat Degradation index= Unstructureless OM (Unstructureless OM + Structureless tissues) • C/N ratios well correlated to degradation index • - Organic composition ≈ similar in SCA & SCC • - In uppermost levels at SCC: high % of AOM, root tissues and • Fungi => higher degradation in microsites associated to Eriophorum roots ?

  10. SCB: 1st regen. stage (Sphagna) SCD: 2nd regen. stage (mixed vegetation) Regenerat.peat? Regenerat.peat? • However, in regenerated « young » peat, the organic composition at SCB and SCD is quite similar (at the top of SCD, more AOM), and once again, more heterogeneous than that of SCC

  11. FINLAND FIE: bare peat FIC: C.rostrata (wet) • As observed for some other sites, the uppermost levels of FIE & FIC have low C/N ratios and high % of AOM => higher OM degradation • In deeper levels, OM is mainly composed of mucilage: • to be correlated with microbial groups (Daniel G. & Edward M. analyses ?)

  12. FIB: Er.vaginatum (dry) FIA: Er.vaginatum (wet) FID: Sphagnum (wet) ? • FIB & FIA present similar OM composition • exept for the dried situation (FIB) which, strangely, presents better preservation of Cyperacea tissues. • - Need more information on the regeneration trend ? When the peat exploitation stopped ?...

  13. Peat organic matter composition Preliminary conclusions • For all sites: • uppermost levels of the « old » peat (present (FRA) or ancient (FRC)) • characterised by higher densities correlated to lower C/N ratios. • regenerating « young » peat characterised by heteregeneous composition in the first regeneration stages, and more homogeneous in the latter ones. • At least at Baupte, La Chaux d’Abel and scottish sites: • high values of C/N in microbial biomass seem to be correlated to high relative pourcentages of (AOM+mucilage) i.e., structureless • inheritant material and micro-organism secretions) – to be confirmed ?

  14. II. Peat organic matter degradation processes Particle size fractionation (200µm) all samples have been completed and data analysis finished except for FRB & CHB. identification of biomarkers • Completed for: • Living plants (see Hyytiälä presentation) • Fine fraction: FR and FB • In progress: • - Finnish, scottish and CH samples

  15. r2 ≈ 0.59 Correlation between %wt of fine fraction (<200µm) and bulk density: an example • globally, positive correlation between the proportion of peat fine fraction • and bulk density • - correlation coefficient is not very high

  16. BAUPTE - Sugar analyses of fine fraction <200μm FBB: bare peat FBA: 1st regener. stage (Er. angustifolium) Total sugars of Erioph.≈ 320 mg/g • evolution with depth of total sugar contents:≈ constant (50 mg/g) • Similar distribution of hemicellulosics at FBB & FBA dominance of arabinose and xylose => vascular plant sources • low % of cellulosic glucose => attests a higher degradation

  17. RUSSEY - Sugar analyses of fine fraction <200μm FRA: bare peat FRC: 2nd regeneration stage Total sugars of living plants ≈ 367 mg/g • FRA: evolution with depth of total sugar contents:≈ constant • the same for the distribution of hemicellulosic sugars. • These are dominated by H. glucose which could derive in part from micro-organism secretions. • -FRC: regenerated peat: • total sugar content ≈ FRA • markers of Cyper. & Sphagna • less % of H. glucose => better preservation ?

  18. RUSSEY - Sugar analyses of fine fraction <200μm FRD: intact area Total sugars of living plants ≈ 367 mg/g • Progressive consumption of total sugars with depth correlated with: • progressive increasing of H. glucose • Progressive increasing of degradation index

  19. ? Sugar analyses of fine fraction <200μm BAUPTE Living plants RUSSEY polyt sph cyp 3 4 3 6 5 4 8 5 4 7 5 7 8 6 6 8 7

  20. Sugar analyses of bulk peat Chaux d’Abel (sampling of nov.2001) polyt 3 sph 3 4 5 4 cyp 7 5 4 3 8 5 6 8 6 6 7 8 ≈ CHC ≈ CHD ≈ CHA

  21. Identification of biomarkers Preliminary conclusions Bare peat: - no significative evolution with depth (Baupte ~ 50 mg/g while Le Russey ~ 200 mg/g) - high quantity of H. glucose partly derived from microbial secretion ? (to be compared with data of microorganism groups) Regenerating peat: even in fine fraction source biomarkers are dominant (arabinose, galactose and xylose) (not enough data to conclure on degradation biomarkers; CH, SC & FI in progress)

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