aquatic mesocosms for data validation : interest, limitations and recommandations laurent lagadic...
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Aquatic mesocosms for data validation :
interest, limitations and recommandations
Laurent Lagadic & Thierry Caquet
Équipe Écotoxicologie et Qualité des Milieux AquatiquesINRA, Rennes
Workshop ‘In situ trialing for ecological and chemical studies
in support of WFD implementation’Pau, France – 14-15 May 2008
Odum (1984) : "bounded and partially enclosed outdoor experimental setups ... falling between laboratory microcosms and the large, complex, real world macrocosms".
Lalli (1990) : "physically confined multitrophic and self-maintaining systems ... whose size is sufficient to enable pertinent sampling and measurements to be made without seriously influencing the structure and dynamics of the system".
Touart (1991) : "an intermediate-sized system ... that can be replicated and manipulated to test both structural and functional parameters".
MesocosmsDefinitions
Studies on populations (including recovery) and between-species interactions Studies on ecological processes
Long-term global scale changesLandscape impacts
BiomonitoringStudies onmechanisms of toxicity(lethal and sublethal effects)
In situ validation and definition ofbiomonitoring strategies in the field
Identification of specific responses
Identification of effect criteriaExperimental validation of tools
OUTDOOR CONDITIONSLABORATORY CONDITIONS
MicrocosmMesocosms
Experimental ponds
Artificial streams
Isolated species
Simplified food-web
Enclosures
Replicability
Complexity - Realism
MesocosmsDefinitions
From Caquet et al. (1989, 2000)
Natural ecosystems
Exposure conditions
Variability - Replicability
Recovery
Effect propagation
Conditions for use of mesocosmsfor data validation
Exposure conditionsInfluence of a tank-mix adjuvant on herbicide (fomesafen)concentration in water
0
50
100
150
200
250
300
350
400
0 48 96
Durée d'exposition (heures)
0
20
40
60
80
100
0 48 96
Durée d'exposition (heures)
Con
cent
ratio
n en
fom
esaf
en (
µg/
L)
F1 (4,4 µg/L nominale)
F2 (22,2 µg/L nominale)
F3 (44,4 µg/L nominale)
F4 (222,2 µg/L nominale)
MF1 (4,4 µg/L nominale)
MF2 (22,2 µg/L nominale)
MF3 (44,4 µg/L nominale)
MF4 (222,2 µg/L nominale)
Indoor microcosms Single species tests
No effect of the adjuvant on herbicide water concentration
0
50
100
150
200
250
300
350
400
0 4 8 12 16 20 24
Temps (jours)
Co
nc
en
tra
tio
n e
n f
om
es
afe
n (
µg
/L)
F3 (44,4 µg/L nominale)F4 (222,2 µg/L nominale)MF3 (44,4 µg/L nominale)MF4 (222,2 µg/L nominale)
ApplicationWith adjuvant
Without adjuvant
From Jumel et al. (2002), Lagadic et al. (2007) and Coutellec et al. (2008)
F3C
Cl
O
CONHSO2CH3
NO2
Exposure conditionsInfluence of a tank-mix adjuvant on herbicide (fomesafen)concentration in water
0
50
100
150
200
250
300
350
400
0 48 96
Durée d'exposition (heures)
0
20
40
60
80
100
0 48 96
Durée d'exposition (heures)
Con
cent
ratio
n en
fom
esaf
en (
µg/
L)
F1 (4,4 µg/L nominale)
F2 (22,2 µg/L nominale)
F3 (44,4 µg/L nominale)
F4 (222,2 µg/L nominale)
MF1 (4,4 µg/L nominale)
MF2 (22,2 µg/L nominale)
MF3 (44,4 µg/L nominale)
MF4 (222,2 µg/L nominale)
Indoor microcosms Outdoor mesocosmsSingle species tests
Without adjuvant
With adjuvant
No effect of the adjuvant on herbicide water concentration
0
50
100
150
200
250
300
350
400
0 4 8 12 16 20 24
Temps (jours)
Co
nc
en
tra
tio
n e
n f
om
es
afe
n (
µg
/L)
F3 (44,4 µg/L nominale)F4 (222,2 µg/L nominale)MF3 (44,4 µg/L nominale)MF4 (222,2 µg/L nominale)
ApplicationWith adjuvant
Without adjuvant
Obvious effect of the adjuvant
From Jumel et al. (2002), Lagadic et al. (2007) and Coutellec et al. (2008)
F3C
Cl
O
CONHSO2CH3
NO2
Variability - Replicability
From Caquet et al. (2001)
Eff
ect
of
treatm
en
t
CV
Number of replicates
Vari
ati
on
betw
een
mean
s (%
)
-300
-250
-200
-150
-100
-50
0
1 2 3 4 5 6 7 8 9 10 11 12
10%20%
40%
60%
80%
100%
Variability in control mesocosms : CV = (s/x)*100
Variability - Replicability
-175
Number of replicates needed to detect a significant reduction of one given effect criterion according to its variability in control mesocosms(t test; = 0,05, 1 - = 0,80)
HARAP – 1999
Recovery is defined as return of a measured parameter (e.g., the abundance of a population) to the normal range of the controls.
CLASSIC – 2002
“Recovery” means the return of a disturbed system to a status comparable to an undisturbed system.Recovery is possible inherently from within the system (autochthonous) or via recolonization (allochthonous).
Recovery has to be used by experts to determine the "Ecologically Acceptable Concentration" (EAC) for a particular compound.
RecoveryDefinitions
DensityHighLow
Low
High
Recolonisation potential
Adapted from Kedwards (2000)
MolluscsCrustaceans
DipteransColeopteransHeteropterans
EphemeropteransOdonates
RecoveryTheoretical relationship between biological traits and recovery
Stability of age structure HighLowGenetic diversity
HighLowVoltinismUni- Multi-
Dispersal capacity HighLow
Natural stochasticityHigh Low
Natural mortalityHigh Low
RecoveryRole of connectivity between static experimental ecosystems
Open mesocosmstreated (n = 4) & untreated (n = 4)
Covered mesocosmstreated (n = 4) & untreated (n = 4)
Principal Response Curve (PRC) analysis of abundance data
April 22, 2003 : treatment with deltamethrin, and covering
Monitoring of effects for more than one year (April ’03 - June ’04)
Study design
From Hanson et al. (2007)
RecoveryRole of connectivity between static experimental ecosystems
Zooplankton
-0.25
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
0.25
0.3
-50 0 50 100 150
Time after treatment (days)
Cdt
Control OpenTreated OpenTreated Covered
***
*********
* *
* *
*
** Other Rotifers
Cyclopoid Adults
Polyarthra sp.
Gastropus sp.
Daphniidae
Mytilina sp.Asplanchnidae
TestudinellaOstracoda
Other Copepodites
Chydoridae
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
bK
Open control
Open treated
Covered treated
In both open and covered ponds, recovery occurredafter 40 days
From Hanson et al. (2007)
RecoveryRole of connectivity between static experimental ecosystems
Benthic macroinvertebrates
Corynoneurinae
Chironominae
Tanypodinae
Baetidae
Physa acutaNematods
Dugesia sp.Lymnaeids
Oligochaetes
EcnomidaeOrthocladiinae
Herpetocypris sp. 1
-5
-4
-3
-2
-1
0
1
2
3
bk
-0.1
0
0.1
0.2
0.3
0.4
0.5
-50 0 50 100 150 200 250 300 350 400
Time after treatment (days)
Cdt
Control Open Treated Open Treated Covered
****
*
*
**
*********
******
***
***
***
***
**
Open control
Open treated
Covered treated
Recovery did not occurin the isolated ponds
Recovery occurred after 60 days in the open mesocosms
From Caquet et al. (2007)
Effect propagationLinking levels of biological organisation
In HCB-exposed snails :
Reduced individual growth
Increased production of eggs
Freshwater snails (Lymnaea) exposed to 3 concentrations of hexachlorobenzene (HCB)in outdoor pondmesocosms
* ** * *
0
5
10
15
20
0 2 4 6 8 10 12Weeks after treatment
Mea
n cu
mul
ated
num
ber
of e
gg-m
asse
s pe
r sn
ail Control
0.5 µg/l
1.25 µg/l
5 µg/l
From Baturo et al. (1995)
Effect propagation
From Caquet (2000) (unpublished)
Chironomini
Notonectidae
Physidae
Dugesiidae Ecnomidae
Asellidae-1,5
-1
-0,5
0
0,5
1
1,5
2
2,5
3
3,5Gastropods
Principal Response Curve (PRC) analysisof the abundance of invertebrate taxa
-0,4
-0,2
0
0,2
0,4
0,6
0,8
1
-5 0 5 10 15 20 25 30Temps écoulé depuis le traitement (Semaines)
Coe
ffic
ient
can
oniq
ue (
Cdt
)
Témoins 0,5 µg/l 1,25 µg/l 5 µg/l
Weeks after treatment
Cdt
Control 0.5 µg/l 1.25 µg/l
Pol
ysac
char
ide
hydr
olys
is e
nzym
e ac
tivity
(µg
gluc
ose
equi
vale
nt/m
in/m
g pr
otei
n)
Glycogen
Corn starch
Rice starch
Hours after treatment
Gly
coge
n co
ncen
trat
ion
(µg/
g fr
esh
wei
ght)
Visceral mass
Mantle
Hours after treatment
From Baturo et al. (1995)
Effect propagationEnhanced glycogen enzymatic breakdownin exposed snails
Effect propagation :Linking levels of biological organisation
Enhanced glycogen
breakdownIncrease in fecundity
Increase in population
density
Effect on CNS (dorsal bodies ?)
Change in neurohormonal control of reproduction
HCB
Explanatory hypothesis
Change in the
structure of gastropod community
From Jumel et al. (2002)
Freshwater snails (Lymnaea) exposed to repeated applicationsof fomesafen (one concentration) in outdoor pondmesocosms
Effect propagation :Linking levels of biological organisation
F3C
Cl
O
CONHSO2CH3
NO2
Effect on reproduction
0
1
2
3
4
0 16 32 48 64
Time (days)
**
*
Ovi
po
sito
ry a
ctiv
ity (
mea
n cu
mul
ated
num
ber
of c
lutc
hes
per
indi
vidu
al)
**
*
Treatments
Time (days)
Fomesafen inhibits reproduction (decreased number of clutches, i.e. fecundity, by individual)
Fomesafen induces :
- enhanced glycogen breakdown
- decrease of sexual steroid levels
Responses of energetic and hormonal biomarkers
0,0
0,2
0,4
0,6
0,8
0 8 16 24 32 40 48 56
Time (days)
Tes
tost
eron
e-lik
e le
vel
(ng/
ovod
iges
tive
glan
d)
0,0
0,2
0,4
0,6
0,8
0 8 16 24 32 40 48 56
Time (days)
Est
radi
ol-li
ke le
vel
(ng/
ovod
iges
tive
glan
d)C
once
ntra
tion
in e
stra
diol
-like
(n
g/ov
otes
tis)
Con
cent
ratio
n in
test
oste
rone
-like
(n
g/ov
otes
tis)
Time (days)
Treatments
0,0
4,0
8,0
12,0
16,0
0 8 12 35 56Time (days)
**G
lyco
gen
conc
entr
atio
n (µ
g/g
fres
h w
eigh
t)
Time (days)
Treatments
From Jumel et al. (2002)
F3C
Cl
O
CONHSO2CH3
NO2
Effect propagation
Conclusions
http://www.rivm.nl./bibliotheek/rapporten/601506009.pdf
Guidance for summarizing and evaluating aquatic micro- and mesocosm studies
de Jong et al., 2008
Many thanks to the people who contributed to the acquisition of the data used in this presentation
Thank you for your attention