Autumn 2004

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WP1 : Comparison between regenerations

NEE

GP

NEE (micromoleCO2/m2/s)

GP(micromoleCO2/m2/s)

RT

OT

(mic

rom

ole

CO

2/m

2/s

)

Difference statistically significant between the three situations with the Kolmogorov Smirnov test.

advancedrecent

Bare peat

Total respiration

y = 0.3764x - 0.9685

R2 = 0.9707

y = 0.2954x - 12.139

R2 = 0.97620

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120

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Plot 3

Plot 1

WP1 : Seasonal variation of the vegetation

y = -0.0077x2 + 3.1811x - 161.86

R2 = 0.9023

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y = -0.0316x2 + 13.6x - 1021.6

R2 = 0.9652

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Seasonal variation of the average surface of photosynthesis (mm2) E. angustifolium

Julian day

Variation of the number of leaves (recent regeneration : E. angustifolium)

Variation of the total surface of Photosynthesis (m²)

Seasonal variation of the average surface of photosynthesis (mm2) E. vaginatum

Julian day

Julian day Julian day0

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0.6

100 120 140 160 180 200 220 240 260

Julian day

Seasonal variation of the vegetation

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Plot 1

Plot 3

Plot 2

Plot 4

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Plot 5

Plot 6

Plot 7

Plot 8

LAI of E. angustifolium (m²/m²) in recent regeneration

00.10.20.30.40.50.60.70.80.9

1

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Plot 5Plot 6Plot 7Plot 8

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Plot 1

Plot 2

Plot 3

Plot 4

Julian Day

Julian Day Julian Day

Julian Day

LAI of E. vaginatum, C. nigra, V. oxycoccos (m²/m²) in advanced regeneration

Density*surface covered by Sphagnum sp. and P. strictum in recent regeneration

Density*surface covered by Sphagnum sp. and P. strictum in advanced regeneration

WP1 : Le Russey, Rtot=f(temperature)

Y=a*ebTair

y = 0.004x1.9451

R2 = 0.9101

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y = 0.1061x1.2123

R2 = 0.8015

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0 5 10 15 20

Tair

Recent and advanced

T10cm

Y=a*ebT10cm

RT

OT

(mic

rom

ole

CO

2/m

2/s

)R

TO

T(m

icro

mo

leC

O2/m

2/s

) Recent and advanced

Model equations for recent and advanced regenerationsGPM=GPMTo*exp(-(((Tair-To)/i)^2))

GP=(GPM*(LAI+g*(Ss*Ds+Sp*Dp)*H))+h

R=Ra+RhRa=a*(LAI+c*(Ss*Ds+Sp*Dp)*H)*exp(b*Tair)

Rh=d*exp(e*(-WT))*exp(f*Tair)

NEE=GP-R

VariablesLAI= Leaf area index for vascular plantsSs= surface covered by Sphagnum sp

Ds= density/density max per Sphagnum spSp= surface covered by Polytrichum Strictum

Dp= density/density max per Polytrichum StrictumTair= air temperature measured in the chamber

WT= Water table levelH= Humidity / Humidity max (index 5)

Simulation of CO2 fluxes for recent and advanced regeneration

Advanced regeneration : NEE

Recent regeneration : NEE

R2 = 0.6530

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0 2 4 6 8 10

R2 = 0.8024

-1

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-1 0 1 2 3 4 5 6 7

NEE simulated(micromoleCO2/m²/s)

NEE measured

NEE simulated(micromoleCO2/m²/s)

NEE measured

 

Recent regeneration

Advanced regeneration

R² 0.8 0.65

GPMTopt 5.305257302 10.71665074

Topt 28.93436074 27.46623043

i 12.74804015 10.53031767

g 0.686054656 0.239181374

h 0.559133724 5.779521552

a 0.02749797 1.88798E-05

c -2.697329139 -29.71719005

b 0.100081352 0.059176796

e -2.689081238 1.007057524

f 0.090518645 -0.009507464

d 0.084341507 4.932094532

Values of parameters established by the software

Simulation of CO2 fluxes for recent and advanced regeneration

Model equations adapted for the bare peat situation,with the total respiration.

R=a*(-WT)^2+b*(-WT)+c*exp(f*Tair)

Variables

Tair= air temperature measured in the chamberWT= Water table level

R2 = 0.8198-0.2

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Bare peat :RtotRtot simulated (micromoleCO2/m²/s)

Rtot measured

Simulation of CO2 fluxes for the bare peat situation

Bare peat

R² 0.82

a 0.09143862

b -0.24965004

c -0.00515133

f 0.11542624

Values of parameters established by the software

Diurnal variation of CO2

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20/05/2004 R2=0.88 recent regeneration 26/04/2005 R2=0.97advanced regeneration

Parameter Value StdErr Parameter Value StdErr

K 1.92E+02 3.13E+01 K 1.38E+02 2.84E+01

A -4.92E-03 1.15E-03 A -6.38E-03 1.96E-03

B 2.97E-01 3.69E-02 B 3.99E-01 5.98E-02

C 9.36E-01 6.91E-02 C 9.87E-01 3.65E-02

D 3.55E-02 3.31E-03 D 4.90E-02 1.82E-03

Topt 3.01E+01   Topt 3.13E+01  

GPM25 4.34E+00   GPM25 5.98E+00  

R25 2.27E+00   R25 3.36E+00  

Q1O 1.43   Q1O 1.63  

Recent regeneration

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Advanced regeneration

Par (micromole/m2/s)

NEE (micromoleCO2/m2/s)

sink

sourceNEE measured

NEE simulated

WP1 : Methane measurement

WP1 : Le Russey, methane fluxes

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COL5

COL6

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COL1

COL2

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Seasonal variation of CH4 fluxes per plot (recent regeneration)

• Variability between plots.

• first prelevement with the lowest water table level.

•Bare peat situation : Day 178 : 4,4nmoleCH4/m²/sThen, WT = 0, no more fluxes.

nmoleCH4/m²/s

nmoleCH4/m²/s

Seasonal variation of CH4 fluxes per plot (advanced regeneration)