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How to integrate biodiversity into APECOSM (Apex Predators ECOSystem Model): a climate driven, DEB-structured model of ecosystem dynamics focusing on tuna. Olivier MAURY, Jean-Christophe POGGIALE
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www.mercator-ocean.fr www.seawifs.com Toward a worldwide comparative analysis of oceanic ecosystems functioning Tuna catches (1990-1997). Courtesy of A. Fonteneau (IRD). Weimerskirch and coll. Identify the processes… …to be ultimately able to develop a reliable predictive capacity
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An ecosystem model integrating bottom-up and top- down processes Mass conservation is structuring ecosystems mechanistic process based approach A mechanistic process based approach where parameters are biologically meaningful constants. Integration of physiology and adaptive behaviour. evolutive structure An evolutive structure to easily add species or new process.
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Hardy, 1924 Link, 2002 Where are the rules? Are there regularities?
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Quinones et al., 2003 Size-spectrum in marine ecosystems Edvardsen et al., 2002 Bianchi et al., 2000 Boudreau and Dickie 1992
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log (Frequency) log (Intensity) 1/f noise (Bak et al. 1987) Mass extinctions (Sneppen et al. 1995) Earthquakes Business failures (Cook and Ormerod 2003) ……. Are size-spectrum just statistical artefacts?
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Woodward et al., 2005 Their regularity reveals strong underlying general mechanisms
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Pinnegar et al., 2003 Ménard et al., 2006
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Jennings and Mackinson, 2003 Jennings et al., 2002 Jennings et al., 2001
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Size is structuring trophic interactions Size is controlling metabolism
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Temperature effects: from molecules to ecosystems? Kooijman, 1989 Clarke and Fraser, 2004
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Clarke and Johnston, 1999 Clarke and Fraser, 2004
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System represented Bio-geochemistery PISCES (O. Aumont) primary producers, light, O2 Bio-geochemistery PISCES (O. Aumont) primary producers, light, O2 Open Ocean Pelagic Ecosystem (OOPE) w, x, y, t Fishing SKJ x, y, t, E, V, G SKJ x, y, t, E, V, G Size Biomass Diversity YFT x, y, t, E, V, G YFT x, y, t, E, V, G ALB x, y, t, E, V, G ALB x, y, t, E, V, G BET x, y, t, E, V, G BET x, y, t, E, V, G Physics NEMO (wind, currents, temper.) Physics NEMO (wind, currents, temper.)
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Open Ocean Pelagic Communities today no taxonomic distinction. 2nd step fishes cephalopods crustaceans Gelatineous N. O. Handegard pers. com. z explicit, depth distribution constrained by light and O 2 x,y 0 z day nightday Migratory community Mesopelagic community Epipelagic community
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Predation energy fluxes Predation is supposed to be opportunistic and only controlled by: Spatial co-occurrence of predator and prey. The ratio of size between organisms. The model conserves energy: predation is a loss of energy for preys and a gain of energy for predators. 0 w1w1 w2w2 Predation energy fluxes weight
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K 1-K ingestion growth reproduction PREYS Structure somatic maintenance somatic maintenance 1- assimilation growth reproduction Eggs ORGANISM gonadic maintenance Energy fluxes through OOPE organisms Modified from Kooijman (2000)
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Main equation for « consumers » dynamics diffusion advection growth starvation reproduction predationageing non local terms
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Toward an « end to end » online coupling
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The variability of primary production propagates through the size-spectrum of the ecosystem. Dissipation Loss Transition Maury et al., 2007
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The variability of temperature modifies non-linearly the energy fluxes through the size-spectrum of the ecosystem. Maury et al., 2007
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Modelling the 15N of OOPCs
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local hydrologyecosystem processes The OOPCs size spectra are spatially explicit and depend on both local hydrology (T, u, v) and ecosystem processes.
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A given species is characterized by its asymptotic weight k at food saturation (J.kg -1.m -3 ) is the distribution function of the energy content of species k at time t [0, + [ and weight w [0, w max ] in 1 m 3 of seawater. The quantity of energy of species k in the weight range [w 1, w 2 ] per m 3 of seawater is given by The distribution function of the number of individuals of species k in terms of weight (kg -1.m -3 ) at (t, w) in 1 m 3 of seawater is linked to energy with Including biodiversity: assumptions/definitions
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At the scale of the whole ecosystem, we define which is the distribution function of the energy content of all the species in the ecosystem (J.kg -1.m -3 ) at time t [0, + [ and weight w [0, w max ] in 1 m 3 of seawater. is independent of k weight Species k w k=w
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The input of eggs R t (J.s -1.m -3 ) into the system due to reproduction is taken into account assuming a Dirichlet boundary condition in w=w egg : The magic question is:
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Integration by part: easy!!
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How to integrate this?? Not so easy!!
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