1. 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

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. FRB : 1st regeneration stage
RUSSEY
FRA : bare peat
FRB : 1st regeneration stage
cumulative %
of org.const.
C/N ratio
density
(g/cm3)
Replicate 2
cumulative %
of org.const.
C/N ratio
density
(g/cm3)
Replicate 3
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. FRC: 2nd regeneration stage FRD : intact area
RUSSEY
FRC: 2nd regeneration stage
FRD : intact area
cumulative %
of org.const.
C/N ratio
density
(g/cm3)
cumulative %
of org.const.
C/N ratio
density
(g/cm3) ? ?
Regenerat.peat?
Replicate 3
Replicate 2
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. BAUPTE FBB : bare peat FBA : E.angustifulium
cumulative %
of org.const.
C/N ratio
density
(g/cm3)
Replicate 3
cumulative %
of org.const.
C/N ratio
density
(g/cm3)
Replicate 1
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. CHAUX D’ABEL CHA : fen CHB : transitional
cumulative %
of org.const.
C/N ratio
density
(g/cm3)
Replicate 2
cumulative %
of org.const.
C/N ratio
density
(g/cm3)
Replicate 3
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. CHAUX D’ABEL CHC : bog CHD : Intact ? ? ?
cumulative %
of org.const.
C/N ratio
density
(g/cm3)
cumulative %
of org.const.
C/N ratio
density
(g/cm3) ? ? ?
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. SCOTLAND SCA: bare peat SCC: 1st regen. stage (Eriophorum)
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. Correlation between %wt of fine fraction (<200µm) and bulk density:
an example
r2 ≈ 0.59
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. Total sugars of living plants ≈ 367 mg/g
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
RUSSEY
BAUPTE
Living plants
polyt
sph
cyp ? 3 4 3 6 4 5 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 7
cyp 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)