Marie Elodie Perga - Gliding from limnology to paleolimnology to study the ecosystem-wide consequences of human pressures on lake food webs
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This was a plenary talk given at the International Paleolimnology Symposium, Glasgow, August 2012.
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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 1992 1994 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
- 3. François Hollande & David Cameron, le 18 mai 2012. REUTERS/Andrew Winning
- 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
- 16. Coring > 200 cores ~8-10 000 sections to be dated (Jenny et al, sub)
- 17. Dating of reference cores Lake Geneva Lake Bourget (Jenny et al, sub)
- 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?
- 22. Reconstructing forcings 1. Climate _ Air temperatures 40 Summer temp anomalies (1857-2008) 30 20 10 0 -10 -20 1860 1880 1900 1920 1940 1960 1980 2000 40 Winter temp anomalies (1857-2008) 30 20 10 0 -10 -20 -30 -40 -50 1860 1880 1900 1920 1940 1960 1980 2000 Histalp Locally monitored data (MeteoFrance)
- 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
- 26. Reconstructing local forcings 1. P concentrations Monitoring data Reconstructed data
- 27. Reconstructing local forcings 11. Fish predation pressure Geneva Daphnia claw length (µm) 700000 160 •Size selective predation hypothesis 600000 150 Fish catches (kg) (Brooks & Dodson, 1965) 500000 400000 140 •Jeppesen E et al.(2002) J. Paleolimnol. 300000 130 200000 120 100000 0 110 1892 1942 1992 Year =-0.511, P=1.58*10-6 Annecy Bourget 250000 150 Daphnia claw length (µm) 40000 145 Daphnia claw length (µm) 145 35000 140 200000 140 Fish catches (kg) Fish catches (kg) 30000 135 135 25000 150000 130 130 125 20000 125 100000 120 15000 115 120 10000 50000 110 5000 115 105 0 100 0 110 1920 1970 1968 1978 1988 1998 Year Year =-0.340, P=0.009 =-0.426, P=0.008 Alric et al, revised
- 29. ANNECY % contribution of CCOS 0 100 50 1937 1939 1943 1948 Temp Fish stocks Nutrients 1951 1955 1959 1963 1967 Year (i) Diatoms 1971 1976 1980 1984 1989 1996 2003 Relative impacts of climate and forcings
- 30. BOURGET % contribution 0 100 1873 50 1884 1899 1914 1923 1936 AUIS Temp Fish stocks Nutrients 1949 1860 1956 1962 Year AFOR 1969 1880 1973 (i) Diatoms 1980 1900 1987 SPAV 1993 1920 1999 2007 1940 1960 Relative impacts of climate and forcings 1980 2000
- 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
- 39. Compared relative impacts of forcings on oxic components (i) Hypoxia 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 HYP 188 189 190 191 192 193 194 195 196 197 198 199 200 201 BOURGET 0 0 0 0 0 0 0 0 0 0 0 0 0 0 HYP 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 GENEVA HYP
- 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 !