@article{fdi:010040826,
  title = {{M}odeling environmental effects on the size-structured energy flow through marine ecosystems. {P}art 2 : {S}imulations},
  author = {{M}aury, {O}livier and {S}hin, {Y}unne-{J}ai and {F}augeras, {B}laise and {B}en {A}ri, {T}amara and {M}arsac, {F}rancis},
  editor = {},
  language = {{ENG}},
  abstract = {{N}umerical simulations using a physiologically-based model of marine ecosystem size spectrum are conducted to study the influence of primary production and temperature on energy flux through marine ecosystems. {I}n stable environmental conditions, the model converges toward a stationary linear log-log size-spectrum. {I}n very productive ecosystems, the model predicts that small size classes are depleted by predation, leading to a curved size-spectrum. {I}t is shown that the absolute level of primary production does not affect the slope of the stationary size-spectrum but has a nonlinear effect on its intercept and hence on the total biomass of consumer organisms (the carrying capacity). {T}hree domains are distinguished: at low primary production, total biomass is independent from production changes because loss processes dominate dissipative processes (biological work); at high production, ecosystem biomass is proportional to primary production because dissipation dominates losses; an intermediate transition domain characterizes mid-production ecosystems. {O}ur results enlighten the paradox of the very high ecosystem biomass/primary production ratios which are observed in poor oceanic regions. {T}hus, maximal dissipation (least action and low ecosystem biomass/primary production ratios) is reached at high primary production levels when the ecosystem is efficient in transferring energy from small sizes to large sizes. {C}onversely, least dissipation (most action and high ecosystem biomass/primary production ratios) characterizes the simulated ecosystem at low primary production levels when it is not efficient in dissipating energy. {I}ncreasing temperature causes enhanced predation mortality and decreases the intercept of the stationary size spectrum, i.e., the total ecosystem biomass. {T}otal biomass varies as the inverse of the {A}rrhenius coefficient in the loss domain. {T}his approximation is no longer true in the dissipation domain where nonlinear dissipation processes dominate over linear loss processes. {O}ur results suggest that in a global warming context, at constant primary production, a 2-4 degrees {C} warming would lead to a 20-43% decrease of ecosystem biomass in oligotrophic regions and to a 15-32% decrease of biomass in eutrophic regions. {O}scillations of primary production or temperature induce waves which propagate along the size-spectrum and which amplify until a "resonant range" which depends on the period of the environmental oscillations. {S}mall organisms oscillate in phase with producers and are bottom-up controlled by primary production oscillations. {I}n the "resonant range", prey and predators oscillate out of phase with alternating periods of top-down and bottom-up controls. {L}arge organisms are not influenced by bottom-up effects of high frequency phytoplankton variability or by oscillations of temperature.},
  keywords = {size spectrum ; numerical simulations ; carrying capacity ; environmental effects ; bioenergetics ; energy flow},
  booktitle = {},
  journal = {{P}rogress in {O}ceanography},
  volume = {74},
  numero = {4},
  pages = {500--514},
  ISSN = {0079-6611},
  year = {2007},
  DOI = {10.1016/j.pocean.2007.05.001},
  URL = {https://www.documentation.ird.fr/hor/fdi:010040826},
}