HIGH-RESOLUTION

PALEOLIMNOLOGY OPENS NEW

MANAGEMENT PERSPECTIVES

FOR LAKES ADAPTATION TO

CLIMATE WARMING

ME Perga1, V. Frossard 2,3, J.P. Jenny1,4,5,6, B.

Alric1, F. Arnaud4, V. Berthon1, J. L. Black7, I.

Domaizon1, , C. Giguet-Covex4, A. Kirkham1, , M.

Magny3, M. Manca8 , A. Marchetto8, L. Millet3, C.

Paillès7, C. Pignol4 ,J. Poulenard4, J.L. Reyss9, F.

Rimet1, P. Sabatier4, O. Savichtcheva1, F.

Sylvestre7, , V. Verneaux3.

ANR VUL-005 2009-2013

.02

PREDICTING ECOLOGICAL CONSEQUENCES OF CC ON LAKES

Schneider & Hook, 2010

Lakes are globally warming up…

Changes in lakes surface temperature 1985-2009

.03

PREDICTING ECOLOGICAL CONSEQUENCES OF CC ON LAKES

Schneider & Hook, 2010

Lakes are globally warming up…

Changes in lakes surface temperature 1985-2009

… With yet different amplitudes and

physical consequences

30% of variance explained by

morphometry

Kraemer et al, 2015

.04

PREDICTING ECOLOGICAL CONSEQUENCES OF CC ON LAKES

Degree of coherence among lakes Regional climate

Physical responses

TOPOLOGY, GEOMORPHOLOGY HYDROLOGY

.05

PREDICTING ECOLOGICAL CONSEQUENCES OF CC ON LAKES

Degree of coherence among lakes Regional climate

Physical responses

Chemical responses

Biological responses

TOPOLOGY, GEOMORPHOLOGY HYDROLOGY

WATERSHED GEOLOGY, HYDROLOGY

BIODIVERSITY

.06

PREDICTING ECOLOGICAL CONSEQUENCES OF CC ON LAKES

Degree of coherence among lakes Regional climate

Physical responses

Chemical responses

Biological responses

TOPOLOGY, GEOMORPHOLOGY HYDROLOGY

WATERSHED GEOLOGY, HYDROLOGY

BIODIVERSITY

The odds of finding the same response of biological

entities in neighboring lakes is about 50:50 (Dokulil, 2013)

.07

Selected examples of the

observation, detection and

attribution of impacts of climate

change on freshwater

resources (IPCC WGII)

CONFOUNDING EFFECTS OF

LOCAL HUMAN ACTIVITIES

.08

Selected examples of the

observation, detection and

attribution of impacts of climate

chnage on freshwater

resources (IPCC WGII)

CONFOUNDING EFFECTS OF

LOCAL HUMAN ACTIVITIES

• « Climate change negatively impacts freshwater ecosystems by changing

streamflow and water quality (high agreement, medium evidence) »

• « Most observed changes of water quality due to climate change are

known from isolated studies, of a small number of variables ».

Bottom anoxia in a spanish reservoir

DOC in UK lakes Lake nutrient content (Australia)

Fecal pollution in californian wetlands

Nutrient flushing in US swamps and reservoirs

Approach Pros Cons

Experimental Mechanistic, in-depth

understanding of processes

Over-simplification

Short-term

Observation Realism Rare long-term datastes (>30 yrs)

Idiosyncracism of responses

Selected monitored parameters

Modelling Comprehensive

understanding, prediction

Physical, chemical and biological

knowledges are not integrated yet

Paleo Mid-to long-term

Responses to CC

Multi-site perspectives

Confounding effects of multiple forcings

Approach Pros Cons

Experimental Mechanistic, in-depth

understanding of processes

Over-simplification

Short-term

Observation Realism Rare long-term datastes (>30 yrs)

Idiosyncracism of responses

Selected monitored parameters

Modelling Comprehensive

understanding, prediction

Physical, chemical and biological

knowledges are not integrated yet

Paleo Mid-to long-term

Responses to CC

Multi-site perspectives

Confounding effects of multiple forcings

• process-oriented comparative design • Combining annually-dated paleo-records and long-term

monitoring data for (i) the dynamics of climate and local ; (ii) the multiple biotic and geochemical changes occurring in lake habitats ;

• Equation solved through modelling

STUDY SITES : 3 DEEP, LARGE, ANTHROPOGENIZED LAKES

GENEVA BOURGET ANNECY

A similar history of eutrophication/re-oligotrophication with yet different intensities

Similar fish communities with slightly different management practices

River regulations

.012

600

800

1000

1200

1400

1600

60

80

100

120

140

160

1850

1860

1870

1880

1890

1900

1910

1920

1930

1940

1950

1960

1970

1980

1990

2000

8

9

10

11

12

13

-30

-20

-10

0

10

20

30

1850

1860

1870

1880

1890

1900

1910

1920

1930

1940

1950

1960

1970

1980

1990

2000

HISTALP

METEO_FRANCE

Annual air temperatures Annual precipitations

Anom

alie

s (

10

-1°C

;

HIS

TA

LP

)

Anom

alie

s (

%;

HIS

TA

LP

)

Air te

mp

era

ture

(°C; M

ete

o-F

rance

)

Pre

cip

itatio

ns

(mm

; Mete

o-

Fra

nce)

Su

rface

te

mp

era

ture

(°C

)

L. GENEVA L. ANNECY L. BOURGET

8

9

10

11

12

13

14

15

1965

1975

1985

1995

2005

8

9

10

11

12

13

14

15

1965

1975

1985

1995

2005

8

9

10

11

12

13

14

15

196

5

197

5

198

5

199

5

200

5

STUDY SITES : 3 DEEP, LARGE LAKES UNDER SIMILAR CLIMATE

WITH DIFFERENT THERMAL VULNERABILITIES

1. Reaching a 3D-perspective

132 cores, 19 missions

INTEGRATION NEO- AND PALEO-DATA OVER MULTIPLE DESCRIPTORS: A CHALLENGE FOR SEDIMENTOLOGISTS

1. Reaching a 3D-perspective

132 cores, 19 missions

Dating by « varve »

countings

Radio-isotope

dating

Historical events

Establish a reference core

2. Reaching an ecologically relevant chronometer & sampling

INTEGRATION NEO- AND PALEO-DATA OVER MULTIPLE DESCRIPTORS: A CHALLENGE FOR SEDIMENTOLOGISTS

1. Reaching a 3D-perspective

132 cores, 19 missions

Dating by « varve »

countings

Radio-isotope

dating

Historical events

Establish a reference core

2. Reaching an ecologically relevant chronometer & sampling

3. Providing 4000 accurately dated samples (+/- 1 year)

In 3 year-time….

INTEGRATION NEO- AND PALEO-DATA OVER MULTIPLE DESCRIPTORS: A CHALLENGE FOR SEDIMENTOLOGISTS

L. GENEVA L. ANNECY L. BOURGET

Terr

igen

ou

s

su

pp

lies (

mg

.cm

-

2.y

r-1)

Dap

hn

ia-i

nfe

rred

TP

(μg

P.L

-1)

Siz

e o

f D

ap

hn

ia-

cla

ws

(μ

m)

A. RIVER

DISCHARGE

B. NUTRIENT

INPUTS

C. FISH

PREDATION

PRESSURE

Year Year Year

RECONSTRUCTED LOCAL HUMAN FORCINGS

- + ++

+ + -

L. GENEVA L. ANNECY L. BOURGET

Terr

igen

ou

s

su

pp

lies (

mg

.cm

-

2.y

r-1)

Dap

hn

ia-i

nfe

rred

TP

(μg

P.L

-1)

Siz

e o

f D

ap

hn

ia-

cla

ws

(μ

m)

A. RIVER

DISCHARGE

B. NUTRIENT

INPUTS

C. FISH

PREDATION

PRESSURE

Year Year Year

RECONSTRUCTED LOCAL HUMAN FORCINGS

- + ++

+ + -

L. GENEVA L. ANNECY L. BOURGET

Terr

igen

ou

s

su

pp

lies (

mg

.cm

-

2.y

r-1)

Dap

hn

ia-i

nfe

rred

TP

(μg

P.L

-1)

Siz

e o

f D

ap

hn

ia-

cla

ws

(μ

m)

A. RIVER

DISCHARGE

B. NUTRIENT

INPUTS

C. FISH

PREDATION

PRESSURE

Year Year Year

RECONSTRUCTED LOCAL HUMAN FORCINGS

- + ++

+ + -

.019

Proces

s scale Observation

level Taxonomic level

Sites Proxies/methodologies

Pela

go

s

Geneva Bourget Annecy

FUNCTION Surface CO2

concentrations δ13C cladoceran remains

COMM.

Diatoms Sub-fossil remains

Cyanobacteria qPCR based methods

Cladocerans Subfossil-remains

Rotifers Resting eggs

GENUS

genetic

diversity

Synech.

(cya) Cloning-sequencing

SPECIES

complex

Daphnia long.

Reproductive

strategies

RFLP-microsat. on resting

eggs

Benth

os

FUNCTION

C cycling δ13C chironomid capsules

Hypoxia Lamination presence,

COMM. Chironomids Subfossil head capsules

RECONSTRUCTED LAKE RESPONSES

-

AD 1935±2

(Jenny at al. 2015)

Hypoxia in lake Bourget

-

AD 1940±2

(Jenny at al. 2015)

Hypoxia in lake Bourget

AD 1945±2

Hypoxia in lake Bourget

-

AD 1950±2

Hypoxia in lake Bourget

-

AD 1955±2

Hypoxia in lake Bourget

-

AD 1960±2

Hypoxia in lake Bourget

-

AD 1970±2

Hypoxia in lake Bourget

AD 1980±2

Hypoxia in lake Bourget

AD 1990±2

Hypoxia in lake Bourget

AD 2000±2

Hypoxia in lake Bourget

.030

Generalized Additive Model (GAM)

What are the environmental factors driving which responses and when?

DISENTANGLING FORCINGS CONTRIBUTION TO OBSERVED ECOLOGICAL CHANGES

DIA

TO

MS

Co

mm

un

itie

s

A. formosa, A.islandica

S. Parvus, D. tenuis

S. binderanus

A. islandica

As

sem

bla

ges

P. Rubescens

Synechoccocus

CL

AD

OC

ER

AN

S

Co

mm

un

itie

s

B. longimanus

L. kindtii B. longimanus

L. kindtii

Bosmina sp.

Bosmina sp.

TP

Fish

predation

pressure

Air

warming

L. GENEVA L. ANNECY L. BOURGET

P. Rubescens Picocyanobacteria

CY

AN

OB

AC

TE

RIA

Ab

un

da

nc

es

A

B

C

+ +

L. GENEVA L. ANNECY L. BOURGET

FOR

CIN

GS

RES

ON

SES

FORCINGS CONTRIBUTION TO PELAGIC CHANGES

Continuous

changes

TP

Fish

predation

pressure

Air

warming

+ +

L. GENEVA L. ANNECY L. BOURGET

FOR

CIN

GS

RES

ON

SES

FORCINGS CONTRIBUTION TO BENTHIC CHANGES

LIT

TO

RA

L

Co

mm

un

itie

s

HY

PO

XIC

Vo

lum

es

L. GENEVA L. ANNECY L. BOURGET

DE

EP

Co

mm

un

itie

s

CH

IRO

NO

MID

S

A

B

++ ++

River

discharg

e

Threshold changes (> 10 μgP/L)

.033

LAKES ECOLOGICAL VULNERABILITY TO CC

PHYSICAL

RESPONSES

TO CC

EXPOSURE

ECOLOGICAL

RESPONSES

TO CC

GEOMORPHOLO

GY

HYDROLOGY • NUTRIENTS

• FISHERIES

MANAGEMENT

PRACTICES

• RIVER FLOW

Control levels for mitigation

strategies

.034

2. Fabien Arnaud, CNRS, EDYTEM.

3. Isabelle Domaizon, INRA, CARRTEL,

4. Florence Sylvestre, IRD, CEREGE

5. Marina Manca, CNR-ISE, Italy

6. Valérie Verneaux, UFC, Chrono-envt

7. Cécile Pignol, EDYTEM

8. Jean-Philippe Jenny, EDYTEM

9. Victor Frossard, Chrono-envt,

10. Benjamin Alric, CARRTEL

11. Vincent Berthon, CARRTEL

12. Laurent Millet, CNRS, Chrono-envt

13. Olga Savichtcheva, INRA, CARRTEL

14. Amy Kirkham, INRA, CARRTEL

15. Emmanuel Naffrechoux, LCME

16. Nathalie Cottin, LCME

17. Jessica Black, CEREGE

18. Christine Pailles, CEREGE

Acknowledgments

Funding Sources French National Research Agency (ANR-VULN 005); CNRS (PEPS program); Région Rhône Alpes, Université de Savoie( France), INRA soutien Post-docs et chercheurs étrangers.