Similaire à Marie Elodie Perga - Gliding from limnology to paleolimnology to study the ecosystem-wide consequences of human pressures on lake food webs
Similaire à Marie Elodie Perga - Gliding from limnology to paleolimnology to study the ecosystem-wide consequences of human pressures on lake food webs (20)
Marie Elodie Perga - Gliding from limnology to paleolimnology to study the ecosystem-wide consequences of human pressures on lake food webs
1. Gliding from limnology to
paleolimnology to study the
ecosystem-wide consequences of
human pressures on lake food webs
Marie-Elodie Perga
Alpine Centre for Research on Lake Food Webs
French National Institute for Agronomical Research
Thonon Les Bains, France
Contributing authors:
B. Alric, F. Arnaud, V. Berthon, D. Debroas, I.
Domaizon, V. Frossard, JP Jenny, A. Kirkham,
M. Manca, A. Marchetto, L. Millet, C. Pignol, JL
Reyss, O. Savichtcheva, F. Sylvestre, V
Verneaux.
2. From Neo to Paleo-limno:
Is it just about switching tools and
timeframe?
14614 papers 2656 papers
7 7
Neo-limno Paleo-limno
6 Eutrophication/re-oligotrophication 6
% total publications
% total publications
5 Climate 5
4 Both 4
3 3
2 2
1 1
0 0
1990
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1996
1998
2000
2002
2004
2006
2008
2010
2012
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
Publication Year Publication Year
Problem-solving approaches Paleoclimatology
predictions
Data from WEB OF KNOWLEDGESM
4. Recent convergence
of Neo and Paleo-limno issues:
An example
Limnology & Oceanography 2009
Climate
Geoscience
Paleo
Canada 1994
Neo
Lake response
“Some lakes/proxies are more
Lakes/compartments are unevenly
adequate than others to
sensitive to climate
reconstruct past climate”
5. Lake sensitivity to climate change
• Lake response to climate is highly context-dependent.
• Interactions between local (nutrient, POPs…) and climate forcings
Similar eutrophication, different lakes and
climates
The strength of interactive effects of climate
and eutrophication are site-specific
Lake sensitivity to climate change shall
depend on the intensity of local forcings?
Comparable lakes submitted to similar
climate, different intensities of local forcings
H: climate effects depends on the intensity of
local human pressures
6. Members
2009-2012
Fabien ARNAUD
Jean-Philippe
Benjamin ALRIC JENNY Jean-Louis Victor
Vincent BERTHON Cécile PIGNOL REYSS FROSSARD
Isabelle DOMAIZON Pierre SABATIER Laurent MILLET
Valérie HAMELET Valérie
Amy KIRKHAM VERNEAUX
Marie-Elodie PERGA
Olga SAVICHTCHEVA
Clément VILLAR Markus MOEST
Piet SPAAK Nathalie COTTIN
Marina MANCA
Aldo Emmanuel
MARCHETTO NAFFRECHOUX
Jessica BLACK
Florence www.inra.fr/iper-retro
SYLVESTRE
7. Our playgrounds
Peri-alpine lakes : large, deep, moderately alkaline, monomictic
Lake Geneva
Lake Annecy
Lake Bourget
20 km
Lake Altitude Length Max Surface
(m asl) (km) Depth area
(m) (km²)
Glacial-tectonics origins
15000-19000 years old
Geneva 372 73 309 581.3
Bourget 240 18 145 44.5
Annecy 446 15 82 27.6
8. Climate forcings on the three lakes
Climate
(Winter temperature anomalies °C)
Annecy
Bourget
Geneva
Year
Auer I et al. (2007) HISTALP - historical instrumental climatological surface time
series of the Greater Alpine Region. Int. J. Climatol. 27:17-46
9. Demography and human pressures over
the last 150 years
Annexation
Demography of the city of Annecy
10. Demography and human pressures over
the last 150 years
Annexion
“France cleaning up the faces of “Marmots are now fashionable”
her new sons to see them”
Demography of the city of Annecy
L’Illustration, Journal Universel, June 30th 1860
11. Demography and human pressures over
the last 150 years
Railway
Franco-Prussian War
Annexion
Crisis
Demography of the city of Annecy
Advertisement from the French railway
company around 1920
12. Demography and human pressures over
the last 150 years
Dvt of tourism
Railway
Franco-Prussian War
Annexion
Crisis
International exposition of tourism and hydroelectrical power,
1925 Bar turning
Hydroelectrical
industry in 1936
Power, industry
(Savoy)
Demography of the city of Annecy
13. Demography and human pressures over
the last 150 years
High intern
Dvt of tourism
immigration
Railway rate
Franco-Prussian War
Annexion
Crisis
Hydroelectrical
power
Demography of the city of Annecy
14. Local human forcings on the three lakes
Nutrient inputs Fisheries management/
Whitefish Stocking
≈15 (µgP L-1)
1936-1997
Annecy
Early stages
Lake TP concentrations (µgP
≈120 (µgP L-1)
1943-1965
Bourget
L-1)
Early stages
1986-
Late stages
≈90 (µgP L-
1)
1970-
Geneva Early stages
Year
15. Objectives
Reconstruct lake-scale biological and
geochemical responses over the last 150 years.
Hierarchize the effects of human perturbations
on lake processes (climate versus local
perturbations-nutrient/fish).
Delineate the underlying processes
18. Core correlations
Laminated facies (from 1936 for lake Bourget, 1963 for Annecy and 1957
for Geneva) : ± 2 years
Non-laminated facies : ± 5-10 years
19. Ecosystem-wide-responses?
Panel of methodologies and scales targeted
Proces
Sites
s scale Observation
Taxonomic level Proxies/methodologies
level Bourge
Geneva Annecy
t
Si/Ti ; Si/Al, Ca/Mg
FUNCTION 1ary production Photosynthetic pigments,
δ13C SOM
Diatoms Sub-fossil remains
Cyanobacteria qPCR based methods
Pelagos
COMM.
Cladocerans Subfossil-remains
Rotifers Resting eggs
GENUS
Synech.
genetic Cloning-sequencing
(cya)
diversity
Daphnia long.
SPECIES RFLP-microsat. on resting
Reproductive
complex eggs
strategies
Sedimentation δ13C SOM, Rock-Eval…
Benthos
FUNCTION Methanogenesis δ13C biological remains
Lamination presence,
Hypoxia
Chironomids
COMM. Chironomids Subfossil head capsules
20. Generalized Additive Model (GAM)
Simpson & Anderson (2009)
Y(response)= f(Climate)+f(Phosphorous inputs)+f(Fish predation or flood…)+ε
Temporal contribution of
covariates to GAM fitted to Y
Univariate or dimension P = 5.21 x 10-4
reduction by ordination
Inferred TP
methods
PC2
Bourget
PC1
Year
What are the environmental factors
driving responses and when?
23. L Reconstructing forcings
o
g 1. Climate _ Precipitations-floods
Flood frequency from
detrital proxies
Locally monitored data (MeteoFrance)
Histalp
160
Precipitations (mm)
150
140
130
120
110
100
90
80
70
60
1860
1880
1900
1920
1940
1960
1980
2000
Year
Long-term changes in annual precipitations
Jenny et al. in prep
24. Reconstructing forcings
1I. P concentrations
Weighted-averaging method from the Central European database
(Berthon, Marchetto et al, in prep)
Lake ANNECY
19
Monitoring data
Reconstructed data 17
TP(µgP.L-1) 15
13
11
9
7
5
1880
1900
1920
1940
1960
1980
2000
Year
25. Reconstructing forcings
1I. P concentrations
Weighted-averaging method from the Central European database
(Berthon, Marchetto et al, in prep)
Lake ANNECY
14 90
Monitoring data 13 80
Daphnia ab. (ing.gsed-1)
Reconstructed data 70
12
60
[TP](µgP.L-1)
11
50
10
40
9
30
8 20
7 10
6 0
1880
1900
1920
1940
1960
1980
2000
Year
31. Relative impacts of climate and forcings
(i) Diatoms
GENEVA
Nutrients
Fish stocks
Low velocity sinker
& resistant to
grazing
Temp
1880
1900
1920
1940
1960
1980
2000
32. Compared relative impacts of forcings on pelagic
components
(i) Diatoms
CLIMATE
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Sum
Win
Nutrients Fish top-down Climate
188 189 190 191 192 193 194 195 196 197 198 199 200 201
ANNECY 0 0 0 0 0 0 0 0 0 0 0 0 0 0
DIA
Summer species Summer species
188 189 190 191 192 193 194 195 196 197 198 199 200 201
0 0 0 0 0 0 0 0 0 0 0 0 0 0
BOURGET
DIA
Early spring species Early spring & late
summer species
188 189 190 191 192 193 194 195 196 197 198 199 200 201
GENEVA 0 0 0 0 0 0 0 0 0 0 0 0 0 0
DIA
late summer species
33. Relative impacts of climate and forcings
(ii) Pelagic C processes
ANNECY BOURGET GENEVA
δ13C(‰) δ13C(‰) δ13C(‰)
Date
OM
OM
Cladoceran
Perga et al, in pre
34. Relative impacts of climate and forcings
(ii) Pelagic C processes
ANNECY BOURGET GENEVA
δ13C(‰) δ13C(‰) δ13C(‰)
Date
OM
Cladoceran
Perga et al, in pre
35. Low [P]
[P] or light [Chl a]
Changes in pelagic δ13C related to [P]
Photic zone
High
δ13CDIC
depth
thermocline
Cladoceran δ13C(‰)
Low
δ13CDIC
1930’s High [P]
2000’s [P] or light [Chl a]
TP(µgP.l- High δ13CDIC
1)
thermocline
depth
Low
δ13CDIC
36. Compared relative impacts of forcings on pelagic
components
(ii) Pelagic C processes
CLIMATE
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Sum
Win
Nutrients Fish top-down Climate
188 189 190 191 192 193 194 195 196 197 198 199 200 201
ANNECY 0 0 0 0 0 0 0 0 0 0 0 0 0 0
DIA
Summer species
188 189 190 191 192 193 194 195 196 197 198 199 200 201
0 0 0 0 0 0 0 0 0 0 0 0 0 0
BOURGET
DIA
Early spring & late summer speci
DCM
188 189 190 191 192 193 194 195 196 197 198 199 200 201
GENEVA 0 0 0 0 0 0 0 0 0 0 0 0 0 0
DIA
late summer species
DCM
37. Compared relative impacts of forcings on pelagic
components
(iii) Cladocerans
CLIMATE
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Sum
Win
Nutrients Fish top-down Climate
ANNECY 188 189 190 191 192 193 194 195 196 197 198 199 200 201
0 0 0 0 0 0 0 0 0 0 0 0 0 0
CLA
Bosmina versus Daphnia in
interaction with fish predation
BOURGET 188 189 190 191 192 193 194 195 196 197 198 199 200 201
0 0 0 0 0 0 0 0 0 0 0 0 0 0
CLA
Thermophilic species+ Pelagic vs littoral spec
GENEVA 188 189 190 191 192 193 194 195 196 197 198 199 200 201
0 0 0 0 0 0 0 0 0 0 0 0 0 0
CLA
Pelagic vs littoral species
(Alric et al, revised) Bosmina species in interaction with fish predation
38. Compared relative impacts of forcings on oxic
components (i) Hypoxia
Forcings contributions to changes in hypoxia volumes (Jenny et al.)
Volume of hypoxic waters (m3)
TP
ANNECY
T°
T°+Ti
BOURGET
T°+Ti
T°+Wind+Ti
GENEVA
Date
40. Compared relative impacts of forcings on oxic
components (ii) chironomid community structure
CLIMATE
Cores depth: 30m, 56m and 65 m
LOCAL FORCINGS
Summer temp July temp
Top-down TP
(Frossard et al, submitted) Winter temp Dec temp Jan temp
41. ANNECY H. grimshawi
S.coracina
Paracladius
Top-down TP Summer temp
1985
1945
30 m
SENSITIVITY TO LOCAL FORCINGS
SENSITIVITY TO CLIMATE
M. contracta
Procladius S.coracina Top-down Jan temp July temp TP
56 m 1945 1940
M. contracta S.coracina TP Summer temp
Procladius
1985
65 m 1945
(Frossard et al, submitted)
42. BOURGET
1980
30 m
SENSITIVITY TO LOCAL FORCINGS
SENSITIVITY TO CLIMATE
1980
90 m
1930 1940
1985
145 m
1930
(Frossard et al, in prep) Oxyphilous Hypoxic tolerant
43. Compared relative impacts of forcings on oxic
components (ii) chironomid community structure
CLIMATE
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Sum
Win
Nutrients Fish top-down Climate
ANNECY
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
LittC
Dee
pC
BOURGET
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
LittC
Dee
pC
44. Compared relative impacts of forcings on oxic
components (iii) Benthic C processes
δ13C(‰)
-43 -38 -33 -28 Lake Annecy
2000
1980
1960
1940 δ13C OM
δ13C Cladoceran remains
1920 δ13C Littoral Chiros
1900
1880 Frossard et al, in prep
45. Compared relative impacts of forcings on oxic
components (iii) Benthic C processes
δ13C(‰)
-43 -38 -33 -28 Lake Annecy
2000
Deep methanogenesis/trophy
1980
1960
1940 δ13C OM
δ13C Cladoceran remains
1920
δ13C Littoral Chiros
δ13C deep chiros
1900
1880
Frossard et al, in prep
46. Compared relative impacts of forcings on oxic
components (iii) Benthic C processes
δ13C(‰)
-40 -35 -30 -25
Lake Bourget
2000
Deep methanogenesis
1980
1960
1940
1920
δ13C OM
1900 δ13C Cladoceran remains
δ13C Littoral Chiros
1880
δ13C deep chiros
1860
1840
Frossard et al, in prep
48. Annecy 1950’s
Fish stocking Warmer summer Cold winter
+ P
+
Fish predation
Increased
size- stratification
selection
Grazers ↑ water
+ ↓Floods
temperature
Decrease Phytoplankton
d size of in summer
grazers
Decrease
d TTE
Increased oxic -
const.
Litt. chiros [O2]interface
Longer oxic
+
isolation of
hypolimnion
Increased oxic -
Deep chiros
const. [O2]interface
+
49. Bourget 1950’s
Fish stocking Warmer summer Cold winter
+ +
Fish predation P
Increased
size- stratification
selection Earlier
Grazers
stratificati ↓Floods
Decrease Phytoplankton on
d size of
grazers
Decrease
d TTE
Increased oxic -
const.
Litt. chiros [O2]interface METHANOGENESIS
Longer oxic Decreased
+ HYPOXIA isolation of O2 renewal
hypolimnion
Increased oxic --
Deep chiros
const. [O2]interface
+
50. Geneva 1950’s
Warmer summer Cold winter
P
+
Fish predation
Increased
size- stratification
selection
Grazers Longer
+
growth
Decrease Phytoplankton
d size of season
grazers
Longer oxic
+
isolation of
hypolimnion
[O2]interface
+
51. Pathways of 1950’s warmer summers effects
Annecy 1950’s Bourget 1950’s Léman 1950’s
Different lake vulnerability to the 1950’s
warmer summers
Essentially related to hydrological and
geomorphological differences between
lakes
•P triggered processes.
52. Annecy since 1985
warmer
Fish stocking Warmer summer winter
++ +
Fish predation P
Increased
size- stratification
selection ↑ water
Grazers +
temperature
Decrease Phytoplankton in summer
d size of 12
Bottom [O2] mg.l-1
grazers 10
8
Decrease 6
d TTE 4
2
Increased oxic -- 0
d-77
d-79
d-81
d-83
d-85
d-87
d-89
d-91
d-93
d-95
d-97
d-99
d-01
d-03
d-05
j-74
j-76
const.
Litt. chiros [O2]interface METHANOGENESIS
Date
Longer oxic
+ HYPOXIA isolation of
hypolimnion
Increased oxic --
Deep chiros
const. [O2]interface
53. Bourget since 1985
spring bloom
warmer
Fish stocking Warmer summer winter
+
Fish predation P
Decrease
d size- stratification
selection Longer
Grazers + growth ↓Floods
Increased Phytoplankton season
size of
grazers DCM
Increased
TTE
+
Litt. chiros [O2]interface METHANOGENESIS
Longer oxic
HYPOXIA isolation of
hypolimnion
Increased oxic --- Decreased O2
Deep chiros
const. [O2]interface renewal
54. Geneva since 1985
warmer
Fish stocking Warmer summer winter
++ +
Fish predation P
Increased
size- stratification
selection Longer
Grazers ++ ↓Floods
growth
Decrease Phytoplankton season
d size of DCM
grazers
METHANOGENESIS?
Longer oxic
HYPOXIA isolation of
hypolimnion
-- Decreased O2
[O2]interface renewal
55. Conclusions-Perspectives
Lakes vulnerability to climate changes
• Hydrological-morphological characteristics count,
even in similar lakes
• Benthic habitats more sensitive to climate than
pelagic/littoral ones in deep lakes : Decoupling?
•Interactions local perturbations-climate stronger in
littoral/pelagic habitats
• P matters, although its impact is stronger on
pelagic/littoral than on benthic processes
•Fisheries management practices count !