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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 Slide 2 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 Slide 3 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. Slide 4 Hardy, 1924 Link, 2002 Where are the rules? Are there regularities? Slide 5 Quinones et al., 2003 Size-spectrum in marine ecosystems Edvardsen et al., 2002 Bianchi et al., 2000 Boudreau and Dickie 1992 Slide 6 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? Slide 7 Woodward et al., 2005 Their regularity reveals strong underlying general mechanisms Slide 8 Pinnegar et al., 2003 Mnard et al., 2006 Slide 9 Jennings and Mackinson, 2003 Jennings et al., 2002 Jennings et al., 2001 Slide 10 Size is structuring trophic interactions Size is controlling metabolism Slide 11 Temperature effects: from molecules to ecosystems? Kooijman, 1989 Clarke and Fraser, 2004 Slide 12 Clarke and Johnston, 1999 Clarke and Fraser, 2004 Slide 13 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.) Slide 14 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 Slide 15 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 Slide 16 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) Slide 17 Main equation for consumers dynamics diffusion advection growth starvation reproduction predationageing non local terms Slide 18 Toward an end to end online coupling Slide 19 The variability of primary production propagates through the size-spectrum of the ecosystem. Dissipation Loss Transition Maury et al., 2007 Slide 20 The variability of temperature modifies non-linearly the energy fluxes through the size-spectrum of the ecosystem. Maury et al., 2007 Slide 21 Modelling the 15N of OOPCs Slide 22 local hydrologyecosystem processes The OOPCs size spectra are spatially explicit and depend on both local hydrology (T, u, v) and ecosystem processes. Slide 23 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 Slide 24 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 Slide 25 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: Slide 26 Integration by part: easy!! Slide 27 How to integrate this?? Not so easy!!