1. introduction - tel.archives-ouvertes.fr · 1. introduction scientific context need for...

Mardi 28 novembre 2006Mardi 28 novembre 2006

Micro analyse quantitative des Micro analyse quantitative des ééllééments traces ments traces dans la calcite de la coquille Saint Jacques dans la calcite de la coquille Saint Jacques

((Pecten Pecten maximusmaximus) par Ablation Laser ICP) par Ablation Laser ICP--MS: MS: une archive journaliune archive journalièère de la re de la biogbiogééochimieochimie des des

environnements côtiers tempenvironnements côtiers tempéérrééss

Quantitative trace Quantitative trace elementelement micro micro analysisanalysis in in calcite shell of the Great calcite shell of the Great ScallopScallop ((Pecten Pecten

maximusmaximus) by Laser Ablation ICP) by Laser Ablation ICP--MS: a MS: a dailydailyarchive of the archive of the biogeochemistrybiogeochemistry in in temperatetemperate

coastalcoastal environmentsenvironments

AurAuréélie BARATSlie BARATS

Outlines

1. Introduction1. Introduction

4. Conclusion4. Conclusion

3. 3. SignificanceSignificance of trace of trace elementelement shellshell profilesprofiles3.1. Background shell concentrations3.1. Background shell concentrations3.2. 3.2. EpisodicEpisodic shell shell enrichmentsenrichments of Ba, Mo and Mnof Ba, Mo and Mn

2. 2. MethodologicalMethodological approachapproach2.1. 2.1. MatrixMatrix--matchedmatched LALA--ICPICP--MS analyses for CaCO3 MS analyses for CaCO3 matrixmatrix2.2. Application to the Great 2.2. Application to the Great ScallopScallop shellshell

1. Introduction

1. Introduction

Scientific context

Need for historical, archeological or paleo ecological archives for the study of environmental changes

(climatic, biological, and anthropogenic)

Need for archives of coastal environment

Bivalve shells:Marine coastal environment for all latitudes;

Incremental CaCO3 growth layers on their skeletal structure.

Marine ecosystemContinental ecosystem

Tree rings CoralsIce cores Cores of sedimentPeat bogs

.

..

.

Trace element enrichment in bivalve shells

Shell

Extrapalleal fluid

. ....

. ..... ....

. .. ... ...

.. .. ..... .

. ..... . . . . ......

.

. ..... ...

. ..... ....

Water column

Hydroclimatic events(resuspension,

floods, upwelling)

Phytoplanktondynamic

Marine pollution

1. Introduction

Redox changes (hypoxia, anoxia)

Dredging activities

Sediment Adapted from Lorrain A., 2002, thesis

Trophic uptakeAqueous uptake

Trace element incorporation within shells

Dissolvedphase

. .... ....

. ..... .. ..

.

.

... ..

. .. .. ...

Particulatephase

Filter feeding organism: up to several liters/day

1. IntroductionPioneering studies

Ba and Mn: tracer of phytoplankton blooms

Chesapeake bay(USA)

Scheldt estuary(Netherland)

Temperate coastalenvironment

Clams(Stetcher et al. 1996)

Spisulasolidissima

Mytilusedulis

Mercenariamercenaria

Mussels(Vander Putten et al. 2000)

Bivalves

Mg and Sr: tracer of seawater temperature

1. IntroductionPioneering studies

Limitations:

Semi-quantitative analyses (No matrix-matched standards)

Seasonal variations with an approximatedatation

Stetcher et al. 1996

Advances:

Micro analyses by LA-ICP-MS of bivalves

Potential tracers of environmental changes

Geographical distributionCoastal environment with

low anthropogenic impactLatitude: 30-60 °NBathymetry: 1-500 m

The Great Scallop shell Pecten maximus

Shell growth rate:Daily striae (50-300µm)Proxy of seawater temperatureInfluenced by the trophic uptake9 months/year (47°N)

Chauvaud et al. 2004

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

1 9 8 7 1 9 8 8 1 9 8 9 1 9 9 0 1 9 9 1 1 9 9 2 1 9 9 3 1 9 9 4 1 9 9 5 1 9 9 6 1 9 9 70

2

4

6

8

1 0

1 2

1 4

1 6

1 8

2 0

Cro

issa

nce

jour

naliè

re (µ

m.j-1

)

Tem

péra

ture

(°C

)

B lo o m d e D ia to m é e s

B lo o m d e d in o f la g e l lé s to x iq u e s

Shel

l gro

wth

rate

(µm

/d)

Tem

pera

ture

(°C

)

Juvenilestage

1. Introduction

Biological tool:The Great Scallop Pecten maximus (L.)

(LEMAR, IUEM)

ObjectivesObjectives

Environmental significance of these trace element shell profiles

Analytical tool:Laser Ablation ICP-MS

(LCABIE)

Bioanalytical tool:Definition of trace element

shell profiles

Trace element shell profiles: tracer/proxy of environmental conditions?

Frequent monitoring of coastalecosystem

(IFREMER, SOMLIT, MAREL)

1. Introduction

2. Methodological approach

2.1. Matrix-matched LA-ICP-MS analyses for CaCO3 matrix

Advantages of this analytical technique:Multi elemental analysis (Mo, Ba, Pb, Mn,…)Micro analyse (20-100 µm) → 1 day

Sensitive: detection limits in the 10ng/g range

2. Methodological approach2.1. Matrix-matched LA-ICP-MS analyses for CaCO3 matrix

Analytical methods

Ionic lens and collision cellQuadrupole

Detector

Plasma torch

Mass spectrometer Interface ICP

Pt cones

Lens

Sample

Ablation cellAr

Laser ablation

Nebulization of a blank solution (1% nitric acid, ultrex grade)

Laser: CETAC LSX 100UV 266 nm,20 Hz

ICP-MS: X7 THERMO ELEMENTAL

Torch

3- Co-precipitation

0.01 0.1 1 10 100 1000TiCrMnAsSeSrMoCdSnBaHgPb

Concentration range (µg/g)0.01 0.1 1 10 100 1000

TiCrMnAsSeSrMoCdSnBaHgPb

0.01 0.1 1 10 100 1000TiCrMnAsSeSrMoCdSnBaHgPb

Concentration range (µg/g)

(NH4OH+ NH4HCO3) ↔ 2CO32- + 2NH4

+ + H2OM2+ + CO3

2- ↔ MCO3(s)

Calibration: No CaCO3 certified standardsMacs 1 (USGS; ≈100 µg.g-1; certification in progress)

Problems and issues of this method

Preparation of CaCO3 standard pellets


1- Dissolution of pure CaCO3 powders with HNO3 (ultrex grade)

2- Spike with a multi elemental solution (25 elements) → 13 concentrations

CaCO3 + H+ ↔ Ca2+ + HCO3-

HCO3- + H+ ↔ CO2(g) + H2O

4- Drying of the precipitates

6- Pressing into pellets (7t, Ø1.3 cm, 2 min)

H HeLi Be B C N O F NeNa Mg Al Si P S Cl ArK Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br KrRb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I XeCs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At RnFr Ra Lr Rf Db Sg Bh Hs Mt

La Ce Pr Nd Pm Sm Eu Gd Db Dy Ho Er Tm YbAc Th Pa U Np Pu Am Cm Bk Cs Es Fm Md No

5- Certification in lab

Repeatability of CaCO3 standard analyses


Normalization against 43Ca (40% in the matrix)

0%

5%

10%

15%

20%

Hg Pb Mo Cd Sn Cu Sr Cr Mn Ba

Rel

ativ

e st

anda

rd d

evia

tions

3.55

23.9 1.98 21.2

21.5 17.9

40.6 22.720.8 17.9

Concentrations in µg.g-1

in this CaCO3 standard

RSD in the range of 5% (n=5)

Laser Laser scanscan

Detection limits


0

10

20

30

40

50

60

70

Sr Cr Cu Mn Hg Sn Cd Pb Ba Mo

Det

ectio

n lim

its (n

g/g) this study

Belloto et al. 2000Price et al. 1997

720 1300 780 280 700

DL in the 10ng.g-1 range

5350

29

137.8 6.8 5.0 3.2 3.0 2.5

BCR CRM 141r(a calcareous loam soil)

MACS-1(CaCO3)

SRM 1c(an argillaceous limestone)

Validation with reference materials


0

100

200

300

400

500

600

700

800

Cr Mn Ni Cu Cd Pb Mn Sr Cr Mn Sr Cd Ba Pb

Con

cent

ratio

ns (µ

g/g)

Measured concentrationsCertified valuesIndicative values

2. Methodological approach

2.2. Application to the Great Scallop shell

20 mm

First year of growth

Scans

2 mm

Application to Scallop shells

Scans Pre cleaning

500 µm Backdating withMEB photography

External calibration with CaCO3standards

Normalizationwith 43Ca

3

2

1

2. Methodological approach2.2. Application to the Great Scallop shell

05000

10000150002000025000

3000035000400004500050000

0 20 40 60 80 100 120

Time (s)

138 B

a si

gnal

inte

nsity

(cps

)

Back

grou

nd in

tegr

atio

nzo

ne

Integration zone

Slice 1 Slice 2 Slice 3 Slice 4 Slice 5

05000

10000150002000025000

3000035000400004500050000

0 20 40 60 80 100 120

Time (s)

138 B

a si

gnal

inte

nsity

(cps

)

Back

grou

nd in

tegr

atio

nzo

ne

Integration zone

Slice 1 Slice 2 Slice 3 Slice 4 Slice 5

05-mai

08-mai

11-mai

14-mai

17-mai

20-mai

23-mai

26-mai

Concentrations (µg/g)

5 mai8 mai

11 mai

14 mai

17 mai

20 mai

23 mai26 mai

45 m

m

Sainte Anne, station SOMLITT, S, Chl a; NO3

-, O2

0

10

20

30

40

50

60

Jan-98 Jul-98 Jan-99 Jul-99 Jan-00 Jul-00 Jan-01 Jul-01 Jan-02 Jul-02 Jan-03 Jul-03 Jan-04 Jul-04

Nitr

ates

(µm

ol/l)

0

2

4

6

8

10


Chl

a (µ

g/l)

Lanvéoc, station IFREMERT, S, Chl a; phytoplankton

0

2

4

6

8


[Ba]

she

ll (µ

g/g)

RoscanvelTrace element concentrations in shells

Regular monitoring of coastal ecosystem: Bay of Brest, France

2. Methodological approach2.2. Application to the Great Scallop shell

Ste AnneSte Anne

RoscanvelRoscanvel

LanvLanvééococ

BayBay of Brestof Brest

Reproducibility in a same shell population

Profile A: steadystate

concentrations for Sr, Mn, Cu, Co, Sn,

Pb

Profile C: steady increasingconcentrations

Profile B: steady state concentrations ponctuated by episodic enrichments

for Ba, Mo, Mn

Con

cent

ratio

ns (µ

g.g-1

)2. Methodological approach

2.2. Application to the Great Scallop shell

Manganese

0

1

2

3

4

5

6

Apr-03 Jun-03 Aug-03 Oct-03 Dec-03

Copper

0

0,2

0,4

0,6

0,8

1

1,2


Strontium

0

500

1000

1500

2000


Magnesium

0

2000

4000

6000

8000

10000


Molybdenum

0

0,2

0,4

0,6

0,8

1

1,2


Barium

0

1

2

3

4

5

6

7


shell 1shell 2shell 3

3. Significance of trace element shell profiles

3.1. Background trace element shell concentrations

y = 0,0061x-0,51

R2 = 0,83

1,E-03

1,E-02

1,E-01

1,E+00

1,E+01

1,E+02

1,E+03

1,E+04

1,E-10 1,E-08 1,E-06 1,E-04 1,E-02 1,E+00

[Me]sw/[Ca]sw

Kd

Sr

Sn

Ba

Pb

Co

MnCu

Mg

104

103

102

10

1

0.1

10-2

10-3

10-10 10-8 10-6 10-4 10-2 1

83.0

])/[]([0061.02

51.0

=

= −

r

CaMeKd sw

Background shell concentrations: 7-year period, 3 shells/year

Trace element affinity with calcium carbonate matrix → partition coefficient Kd

3. Significance of trace element shell profiles3.1. Background trace element shell concentrations

Calcite (trigonal structure)Aragonite (orthorombic structure)Other

Enric

hed

Dep

lete

d

Trace element background concentration:

sw

calc

CaMeCaMeKd

])/[]([])/[]([

=

1. Dependant on seawatercomposition

2. Independent on the precipitation structures?

51.0])/[]([0061.0])/[]([ swcalc CaMeCaMe =

1,E-04

1,E-03

1,E-02

1,E-01

1,E+00

1,E+01

1,E+02

1,E+03

1,E+04

7 8 9 10 11-log Ks

Kd Mineral

MgMn Cu Co

100

10.1

0.01

10

10-3

10-4

103

104

Rimstidt et al. 1998

1,E-04

1,E-03

1,E-02

1,E-01

1,E+00

1,E+01

1,E+02

1,E+03

1,E+04

7 8 9 10 11-log Ks

Kd

Mg

Mn

Cu

Co100

10.1

0.01

10

103

104

10-3

10-4

BiogenicMineral

1,E-04

1,E-03

1,E-02

1,E-01

1,E+00

1,E+01

1,E+02

1,E+03

1,E+04

7 8 9 10 11 12 13 14-log Ks

Kd

Mineral

Rimstidt et al. 1998

BaSr

Pb100

10.1

0.01

10

10-3

10-4

103

104

1,E-04

1,E-03

1,E-02

1,E-01

1,E+00

1,E+01

1,E+02

1,E+03

1,E+04

7 8 9 10 11 12 13 14-log Ks

Kd

104

100

10.1

0.01

10-3

10-4

103

10

BaSr

Pb

Biogenic

Mineral


Trace element enrichmentdependant on:

1. The ionic radii of Me2+

2. The solubility constants within CaCO3

3. The formation of biogenic calcite

997.0;10.2 283.08 == −− rKsKd

Ionic radii of Me2+ < Ionic radii of Ca2+ Ionic radii of Me2+ > Ionic radii of Ca2+

Structure of precipitation

Calcite Aragonite

904.0;10.5 248.114 == −− rKsKd

R2 = 0,85

0

2

4

6

0,3 0,5 0,7 0,9 1,1 1,3Average Pb concentrations (µg/g)

Ave

rage

Mn

conc

entra

tions

(µg/

g)

Mn and Pb annual background concentrations (Bay of Brest, 1998-2004)

Related to hydroclimaticconditions?


Similar crustal sources?

R2 = 0,53

R2 = 0,45

0

2

4

6

13 15 17Temperature (°C)

Ave

rage

Mn

conc

entra

tions

(µg/

g)

0,0

0,5

1,0

1,5

2,0

Ave

rage

Pb

conc

entra

tions

(µg/

g)

Mn

Pb

0

1

2

AMJJASOND Shel

l con

cent

ratio

n (µ

g/g)

Particulate phase

Dissolved phase

PhysiologyShell

Extrapalleal fluid

. ....

. .... ....

. ....

. .... ... ....

. .. ... .... .. ..

... .

.. .. ..... .

. ..... . . . . .........

. ..... ...

. ..... ....

Water column

1

Sediment

Structure of precipitation

Solubilityconstants within

carbonates

2

3


Prediction of seawaterconcentrations

904.0

])/[]([10.2])/[]([2

48.113

=

=

r

CaMeKsCaMe calcsw

Calcite structure

3. Significance of trace element shell profiles

3.2. Episodic shell enrichments

SPAIN

FRANCE

NORW

AY0°

10°E

10°W

50°N

40°N

60°N

30°N

70°N

Coastal bay environment:

• Bay of Brest (France)

• Ria de Vigo (Spain)

Coastal environment influenced by major estuaries:

• Loire : Belle Ile or Quiberon (France);

• Seine: Seine bay (France).

3. Significance of trace element shell profiles3.2. Episodic shell enrichments

0

1

Apr-04 Oct-04


0

1

2

Apr-00 Oct-00

0

1

2

Apr-00 Oct-00

0

1

Apr-00 Oct-00

0

2

Apr-04 Oct-04

0

2

Apr-00 Oct-00

0

1

Apr-00 Oct-00

0

2

4

6

Apr-00 Oct-00

0

5

Apr-04 Oct-04

0

5

10

15

Apr-00 Oct-00

0

5

Apr-00 Oct-00

0

5

10

15

Apr-00 Oct-00

MolybdenumBariumManganese


Seine BayFrance

Bay of BrestFrance

Ria de VigoSpain

Belle IleFrance

Con

cent

ratio

ns (µ

g/g)

0

0,8

1,6

Apr-98 Oct-98 Apr-99 Oct-99 Apr-00 Oct-00 Apr-01 Oct-01 Apr-02 Oct-02 Apr-03 Oct-03 Apr-04 Oct-04

[Mo]

she

ll (µ

g/g)

20 J

uly

0

2

4

6

8


[Ba]

she

ll (µ

g/g)

Molybdenum

Barium


May

6 Ju

ne

12 O

ctob

er

Early summer (June-July)Late summer (August-September)

Mo and Ba shell profiles (Bay of Brest, 1998-2004)

Episodic shell enrichments:

Intensive (particularly for Mo);

Ubiquitous in different coastal environments;

Periodic occurrence:• in spring for Mo (generally in May);• in early or late summer for Ba.

Comparison with shell growth rate

Comparison with environmental monitoring variables:

• Hydrological: temperature, salinity, chlorophyll a

• Biological: dominant and reccurent phytoplancton species:−Rhizosolenia spp./Pseudonitzschia spp. (diatoms) for Mo− diatoms of Chaetoceros spp./dinoflagelates of Gymnodynium spp. for Ba

Molybdenum

Barium


0

1

2

3

4

5

Apr-03 Jun-03 Aug-03 Oct-03

[Ba]

she

ll (µ

g/g)

0

2

4

6

8

Chl

a (µ

g/g)

[Ba]

she

ll(µ

g/g)

Chl

a(µ

g/l)

0

0,5

1


[Mo]

she

ll (µ

g/g)

0

2

4

6

8

Chl

a (µ

g/l)

Molybdenum

Barium

?

?

?

Influence of the total phytoplancton

biomass?

Statistical evaluation(1998-2004):

r=0.28, p>0.05, n=37


Early summer: r=0.22, p>0.05, n=20

Late summer: r=0.79, p<0.05, n=16


Comparison with chlorophyll a concentrations

0

0,5

1


[Mo]

she

ll (µ

g/g)

0

50000

100000

Phyt

opla

nkto

n (c

ell/l

)

Rhizosolenia spp.Pseudonitzchia spp.

[Mo]

she

ll(µ

g/g)

Phyt

opla

nkto

n(c

ell/l

)

0

1

2

3

4

5


[Ba]

she

ll (µ

g/g)

0

500000

1000000

1500000

2000000

cell/

l of p

hyto

plan

kton

Chaetoceros spp.Gymnodynium spp.

[Ba]

she

ll(µ

g/g)

Phyt

opla

nkto

n(c

ell/l

)

Molybdenum

Barium

?

Influence of the phytoplankton

speciation?


Pseudonitszchia spp.(r=0.72, p<0.05, n=37)

Rhizosolenia spp. (r=0.28, p>0.05, n=37)


Early summer: Chaetocerosspp. (r=-0.44, p<0.05, n=20)

Late summer: Gymnodyniumspp. (r=-0.01, p>0.05, n=16)


Comparison with phytoplankton speciation

0

1

2

AMJJASOND Shel

l con

cent

ratio

n (µ

g/g)

Dissolvedphase

Particulatephase

PhysiologyShell

Extrapalleal fluid

. ....

. .... ....

. ....

. .... .. ....

. .. ... .... .

.

.

.

.

.

..

.. .. ..... .

. ..... . . . . .........

. ..... ...

. ..... ....

Water column

Sediment

Mo


Phytoplankton blooms

MoO42-

Ba2+

PrecipitationUptake

Adsorption

Scavenging

BaSO4 (s)

.. . ...

Pelagic source

Trophic uptake

Ba

Summer (diatomsand dinoflagelates)

Spring (diatoms)

Ba → tracer of total phytoplankton biomass?Mo → tracer of specific diatom blooms?

Mo similarto Ba?

Sampling zone

Bay of Seine

HonfeurSeine river

Le Havre

Luc buoyCoastal zone Estuarine zone

3°W

France46°N

0° 4°E

50°N

4°W

HTZ


Mn shell profiles (Seine bay, 2004)

0

2

4

6

8


[Mn]

she

ll (µ

g/g)


8 Aug.

9 Apr.

2 Jun.

9 Jul.

18 Jul.28 Aug. 26 Sep.

Bay of Seine

R2 = 0,97

0

2

4

6

8

0 100 200 300 400

Mn particulate flux (kg/d)[M

n] s

hell

(µg/

g)

From April to July

[Mn]

she

ll(µ

g/g)

Mn particulate flux (kg/d)

From August to October

Mn shell concentrations mainlyinfluenced by riverine inputs

Specific enrichment of Mn shellconcentrations in late summer


Mn shell profiles (Bay of Seine, 2004): influence of riverine inputs

????

0

2

4

6

8


Mn

conc

entra

tions

(µg/

g)


0

2

4

6

8

10


Parti

cula

te fl

ux (k

g/s)

0

200

400

600

800

Sein

e flo

w ra

te (m

3/s)

Particulate flux

Flow rate

Seine river

Bay of Seine

[Mn]

she

ll(µ

g/g)

Part

icul

ate

flux

(kg/

s)

Sein

e flo

w ra

te (m

3/s)

0

2

4

6

8


Mn

conc

entr

atio

ns (µ

g/g)


Estuary (High Turbidity zone)

50

60

70

80

90

100


Oxy

gen

satu

ratio

n (%

)

Seine Bay

60

80

100

120

140


Oxy

gen

satu

ratio

n (%

) Bay of Seine

Estuary (high turbidity zone)


Mn shell profiles (Seine bay, 2004): influence of redox conditions

Specific summer Mn shellenrichments supported by

reducing conditions :

in the estuary

at SWI in the bay

[Mn]

she

ll(µ

g/g)

Oxy

gen

satu

ratio

n (%

)O

xyge

nsa

tura

tion

(%)

Bay of Seine

Phase dissoute

PhysiologyShell

Extrapalleal fluid

. ....

. .... ....

. ....

. .... ... ....

.

...

. ...

.

.. ...

.

.. .. ..... .

. ..... . . . . .........

. ..... ...

. ..... ....

Water column

Sediment

Benthicreduction

Mn

Seine river

Seine estuary(HTZ)

. ......

. .... ....

. ....

. .... ..

.

.. ..

. ..... ...

. ..... ....

.... ...

.. ..

. ......

. .... ....

. ....

. .... ..... ..

. ..... ...

. ..... ....

. .... ....

. ...... ..

.... ...

.. ..

. .... ....

. ...... ..

.... ...

.. ..

. .... ....

. ...... ..

Redox changes

. ......

. .... ....

. ....

. .... ..... ..

. ..... ...

. ..... ....

. .... ...

. .


Desorptionwith salinity

Seine bay

Reduction of particulate Mn

0

2

4

6

8


[Mn]

she

ll (µ

g/g)

4. Conclusion

4. Conclusion

Development of a bioanalytical tool: the Great Scallop + LA-ICP-MS→ Definition of quantitative and chronological trace element profiles along

the calcite shell

→ Methodological approach adaptable to others CaCO3 matrices

Scientific inputs

Trace element profiles in Pecten maximus shells as an archive :• with Ba and Mo of phytoplankton dynamic

Ba → summer total phytoplankton biomass?

Mo → phytoplankton speciation?

• with Mn of particulate riverine inputs and redox processes

Trace element shell profiles → archive of transient events for coastal environment

• Significant and transient Mo shell enrichments during spring diatom blooms → Mo as a conservative behavior in the seawater?

4. Conclusion

1 Analytical development (LCABIE)Improvement of the detection limits, of the analysis time (programmation) → use of

femtosecond laserIsotopic measurement (tracer of biogeochemical processes?) → use of femtosecond

laser coupled with a multi collector (MC) ICP-MS.

2 Biological model (LEMAR)

Fossile or historical shells;

Others species:

• Argopecten purpuratus (Chile)

• Comptopallium radula (New Caledonia)

• Polar species (Antartica)

Thank you for your attention

Merci pour votre attention

Acknowledgments

Merci à tous les membres du LCABIE et ceux du LEMAR: cette alliance béarno-bretonne a largement contribué à

l’aboutissement de cette thèse.Je tiens également à remercier tout mon entourage pour

m’avoir toujours encouragée dans cette voie.

1. introduction - tel.archives-ouvertes.fr · 1. introduction scientific context need for...

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