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Biochemical characteristics of peat organic matter and distribution Biochemical characteristics of peat organic matter and distribution of testate amoebae patterns in naturally regenerating cutover of testate amoebae patterns in naturally regenerating cutover SphagnumSphagnum peatlands of the Jura Mountains peatlands of the Jura Mountains

F. Laggoun-Defarge1, E. Mitchell2,3, D. Gilbert4, B. Warner5, L. Comont1, J.-R. Disnar1 & A. Buttler3,4

11Earth Sc. Inst., CNRS-Univ. Orleans, FranceEarth Sc. Inst., CNRS-Univ. Orleans, France22Univ. Alaska, Anchorage, USAUniv. Alaska, Anchorage, USA33EPFL & WSL-AR, Lausanne, SwitzerlandEPFL & WSL-AR, Lausanne, Switzerland 44Univ. Franche-Comte, Besançon, FranceUniv. Franche-Comte, Besançon, France55Univ. Waterloo, Ontario, CanadaUniv. Waterloo, Ontario, Canada

Which vegetation to promote ?Which related diversity ?

CUTOVER BOGSCUTOVER BOGS

CO2CH4

REGENERATED BOGSREGENERATED BOGS

CH4 CO2

Which microbial communities and processes ?Fate of organic matter ? Biomarkers ?

Starting conditions for potential restoration:Water table ?Chemical properties ?

Abandoned peatlands Abandoned peatlands Peatlands designated for restorationPeatlands designated for restoration

Restablish primary productionRestablish primary productionLong-term C-sequestrationLong-term C-sequestration?

RECIPE (EC FP5RTD) RECIPE (EC FP5RTD) “Reconciling commercial exploitation of peat “Reconciling commercial exploitation of peat with biodiversity in peatland ecosystems”with biodiversity in peatland ecosystems”

RECIPE: cutover Sphagnum-dominated peatlands that are being regenerating

studied sites: range of regeneration stages

France

Switzerland

N

La chaux d’Abel/CH

wet fenearly regeneration stage

dry boglater regeneration stage

non exploited area: reference

The sites: La Chaux d’Abel

0-3 cm amoebae

1 m profiles: 3 X 8 depths

OM analyses :-C, N-Micromorphology-Sugars-bacteria

SPECIFIC OBJECTIVES

determine biochemical characteristics of peat organic matter

determine biodiversity of microorganisms (testate amoebae)

Identification of bioindicators of environmental changes

Clues for the functioning of the system

C/N ratios and microscopic counting

(1/3) La Chaux d’Abel / poor fen (early regeneration stage)CA.1 Sphagnum & Polytrichum

Regenerating litter

“Old” catotelm peat

C/N ratios and microscopic counting (2/3)

CA.5 Sphagnum & Polytrichum

La Chaux d’Abel / bog (later regeneration stage)

Regenerating litter

“Old” catotelm peat

C/N ratios and microscopic counting

(3/3) La Chaux d’Abel (non exploited area)

Vascular plant remains

Higher degradation

Vascular plant remains

Higher degradation

Drainage phase ?Drainage phase ?

Drainage phase ?Drainage phase ?

Markers of organic sources(sugar analyses)

ERIOPHORUMERIOPHORUM

XyloseXyloseArabinoseArabinose

POLYTRICHUMPOLYTRICHUMMannose HMannose H

SPHAIGNESSPHAIGNES

RhamnoseRhamnoseGalactoseGalactose

S. rubellum

Rhm

Gal

%

ERIOPHORUM

Ara

Xyl

%

POLYTRICHUM Man H

%

S. fallax

Rhm

Gal

%

Living plants

sugar analyses

ERIOPHORUMERIOPHORUM

POLYTRICHUMPOLYTRICHUM

SPHAIGNESSPHAIGNES

XyloseXyloseArabinoseArabinose

Mannose HMannose HRhamnoseRhamnoseGalactoseGalactose

La Chaux d’Abel / regenerated bog

% Arabinose et Xylose

d

ep

th (

cm

)

% Mannose

Polytrichum- dominated peatRegenerating litter

vascular plant-dominated peat

higher degradation

Total sugar content in CA.5 [mg/g]

ERIOPHORUMERIOPHORUM

POLYTRICHUMPOLYTRICHUM

SPHAIGNESSPHAIGNES

XyloseXyloseArabinoseArabinose

Mannose HMannose HRhamnoseRhamnoseGalactoseGalactose

% Glucose % Xylose % Man, Ara, Fuc, Rib

sugar analyses d

ep

th (

cm

)La Chaux d’Abel / non-exploted area

Total sugar content in CA.6 [mg/g]

bacteria counting (La Chaux d’Abel)

Taille échantillon Taille échantillon de départ de départ

density ofdensity of bacteria/g bacteria/g fresh peatfresh peat

BIOMASSBIOMASSCarbonCarbon

BiovolumeBiovolume

DEP

TH

(cm

)

REGENERATED Zone

Abondance b/g.dry sampl.Biomass mgC.g

CA 5

NON EXPLOITED Zone

Abondance b/g.dry sampl.Biomass mgC.g

CA 6

DEP

TH

(cm

)

Drainage phasesDrainage phases

Regenerating litter

« Old » peat

Testate amoebae

A dominant group of protozoa in Sphagnum-dominated peatlands.

They are numerous & diverse. Like other microorganisms they have

a higher turnover rate than most other groups of organisms usually used as bioindicators.

Testate amoebaeNumerical analysesNumerical analyses

- Existing database from the Jura Mountains (Mitchell et al., 1999)used to derive transfer functions for pH and the depth of water table (DWT)

- These transfer functions used to infer pH and DWT from the regenerationsequence samples

- A species x samples matrix created with these 2 data (only common speciesto both data sets were kept)

- A conservative taxon. approach used & relative abondance of each speciesin each sample calculated

- Program WACALIB used to determine ecological optima of species and infer pH & DWT values of the samples

- Inferred pH vs inferred DWT for the regeneration sequence => How these 2 variables change along the sequence

CA-1-1

CA-1-2

CA-1-3

CA-2-1

CA-2-2

CA-2-3

CA-4-1

CA-4-2

CA-4-3

CA-5-1

CA-5-2CA-5-3

CA-6-1

CA-6-2

CA-6-3

10.00 3.99

16.24

4.26

22.48

4.53

28.72

4.80

34.95

5.07

Depth to the water table [cm]

pH CA-4

CA1&2

CA-5&6

CA-1

CA-5

CA-2

CA-6

CA-4

Hyalosphenia papilioNebela tinctaAssulina muscorumAmphitrema flavumEuglypha ciliataCorythion dubiumNebela tincta var. majorAssulina seminulumNebela militarisPhryganella acropodiaEuglypha compressaHeleopera sylvaticaHyalosphenia elegans

Community structure in the regeneration sequence

Conclusions

- A continuous trend from wet to drier / more acidic conditions thanks to testate amoebae communities (from Sphagnum mosses) Similar approach can be applied: establishment of a stratigraphy communities in peat cores to monitor changes through time

- OM composition of regenerating litters is similar to that of intact zone (C/N: 60-80)

- early regeneration: homogeneous (mainly Sphagnum remains)- late regeneration: heterogeneous (Sph. & Polyt. remains, AOM), better preservation of monosaccharides

- Specific indicators of organic sources identified from sugar analyses:- Reconstitution of different plant successions- higher degradation of OM associated with vascular plant settlement