Estimation of DEB parameters Bas Kooijman Dept theoretical biology Vrije Universiteit Amsterdam Marseille, 2007/01/18

Auxiliary theory Quantities that are easy to measure (e.g. respiration, body weight) have contributions form several processes  they are not suitable as variables in explenatory models Variables in explenatory models are not directly measurable  we need auxiliary theory to link core theory to measurements Standard DEB model : isomorph with 1 reserve & 1 structure that feeds on 1 type of food

DEB parameters primary parameters determine food uptake changes of state variables (reserve, maturity, structure) compound parameters: functions of primary parameters composition parameters food, reserve, structure, products (feaces, N-waste) thermodynamic parameters free energies (chemical potentials) entropies dissipating heat

Reserve & maturity: hidden Maturity: information, not mass or energy quantified as cumulated mass of reserve that is invested Scale reserve & maturity

Growth at constant food 3.7 time, dultimate length, mm length, mm time Length L. at birth ultimate L. von Bert growth rate energy conductance maint. rate coefficient shape coefficient Von Bert growth rate -1, d Von Bertalanffy growth curve:

measured quantities  primary pars Standard DEB model (isomorph, 1 reserve, 1 structure) reserve & maturity: hidden variables measured for 2 food levels primary parameters

One-sample case

Two-sample case: D. magna 20°C Optimality of life history parameters?

Primary  thermodynamic pars Given primary parameters: get composition parameters get mass fluxes (respiration) get entropies, free energies

Reserve vs structure Kcal/g wet weight cumulative fraction time, dtime of reserve depletion, d protein lipid carbohydrate Data from Whyte J.N.C., Englar J.R. & Carswell (1990). Aquaculture 90: Body mass in starving pacific oyster Crassooestrea gigas at 10°C reserve structure

Reserve E vs structure V

100 g wet weighttotalproteinlipidcarbohydrate  C M C0, kcal  C J CM, kcal/d  C, kJ/C-mol M C0, C-mol J CM, mmol/d M CE =M E, mol/mol M CV =M V, mol/molt 0 = 200 d M CV =M V, mol/molt 0 = 400 d M CV =M V, mol/molt 0 = 600 d