Diapositive 1

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
FRA bare peat
RUSSEY
FRB 1st regeneration stage
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
RUSSEY
FRC 2nd regeneration stage
FRD intact area
?
?
Regenerat.peat?
Replicate 2
Replicate 3

• Considering density, C/N, org const. evolution gt
  limit between old peat and regenerat. peat
  20-25cms
• regenerating peat a nice plant succession !
  heterogeneous org. composition
• Bulk characteristics of FRDs OM strangely
  similar to that of FRC ? Except the more
  homogeneous composition of uppermost peat (Sph.
  mainly)

6
FBB bare peat
BAUPTE
FBA E.angustifulium

• Higher density in superficial peat levels (3
  4) correlated (for FBA) with lower C/N ratios gt
  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).

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CHAUX DABEL
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
CHC bog
CHAUX DABEL
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 gt higher degradation in microsites
  associated to Eriophorum roots ?

10
SCD 2nd regen. stage (mixed vegetation)
SCB 1st regen. stage (Sphagna)
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

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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 gt higher OM degradation
• In deeper levels, OM is mainly composed of
  mucilage
• to be correlated with microbial groups (Daniel G.
  Edward M. analyses ?)

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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 dAbel and scottish
  sites
• high values of C/N in microbial biomass seem to
  be correlated to high relative pourcentages of
  (AOMmucilage) i.e., structureless
• inheritant material and micro-organism
  secretions) to be confirmed ?

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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

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Correlation between wt of fine fraction (lt200µm)
and bulk density an example

• globally, positive correlation between the
  proportion of peat fine fraction
• and bulk density
• - correlation coefficient is not very high

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BAUPTE - Sugar analyses of fine fraction lt200µm
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 gt
  vascular plant sources
• low of cellulosic glucose gt attests a higher
  degradation

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RUSSEY - Sugar analyses of fine fraction lt200µm
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 gt better preservation ?

18
RUSSEY - Sugar analyses of fine fraction lt200µm
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

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Sugar analyses of fine fraction lt200µm
BAUPTE
Living plants
RUSSEY
polyt
sph
cyp
3
4
6
3
5
4
8
5
4
7
7
5
6
8
6
8
7
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Sugar analyses of bulk peat
Chaux dAbel (sampling of nov.2001)
polyt
3
3
sph
4
5
4
cyp
7
5
4
3
8
5
6
6
8
6
7
8
CHC
CHD
CHA
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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)