OSMOSE-ROMS coupled ecosystem model demonstrates emergent behaviour
A shift in trophodynamic relationships in the OSMOSE-ROMS coupled end-to-end ecosystem model is a product of the models emergent behaviour. This atypical for coupled ecosystem models outcome exhibits time-dependent plasticity in dynamic species-to-species relationships, as observed in all ecosystems.
Published in the Ecological Modelling, the approach captures a new range of dynamics that may provide greater insight into the effects of fishing and climate. The case study focused on Benguela, but OSMOSE is already being coupled different biogeochemical lower trophic level models to study Adriatic, Aegian and North Sea ecosystems in the same two-way online mode, under the MEECE Program (www.meece.eu).
Travers et al. couple ROMS N2P2Z2D2 to the Object-oriented Simulator of Marine ecOSystems Exploitation (OSMOSE) through a two-way size-based predation process, and compare the effect of two-way coupling versus a one-way forcing of low (plankton) and high (fish and euphausiids) trophic levels on plankton mortality and on food web pathways.
The comparisons of one-way forcing and two-way coupling show how feedbacks may affect abundance, food web structure and food web function and emphasize the need to critically examine the consequences of different model architectures when seeking to predict the effects of fishing and climate change.
The coupling demonstrated simultaneous top-down and bottom-up effects: a top-down effect from higher trophic level organisms down to plankton groups, and a bottom-up effect on relative dominance of different trophodynamic pathways.
As the authors point out the results are ultimately a function of model architecture and the selection of a favoured approach should ultimately depend on systematic validation with data, a real challenge when few programs monitor all components of marine ecosystems on the same time and space scales.
The study was supported by EUR-OCEANS and MEECE programs. The OSMOSE multi-species model is part of MEECE Model Library, and is currently applied to the Adriatic, Aegian and North Sea with the same two-way online approach.|
Summary for MEECE Research Highlights by Ivo Grigorov
Travers M., Shin Y.-J., Jennings S., Machu E., Huggett J.A., Field J., Cury P., 2009. Two-way coupling versus one-way forcing of plankton and fish models to predict ecosystem changes in the Benguela. Ecological Modelling, 220: 3089-3099.
click to science direct
Travers et al. 2009. Changes in food web structure under scenarios of overfishing in the southern Benguela: Comparison of the Ecosim and OSMOSE modelling approaches, Journal of Marine Systems, http://dx.doi.org/10.1016/j.jmarsys.2009.07.005
Marzloff, M., Yunne-Jai Shin, Jorge Tam, Morgane Travers, Arnaud Bertrand 2009. Trophic structure of the Peruvian marine ecosystem in 2000-2006: Insights on the effects of management scenarios for the hake fishery using the IBM trophic model Osmose, Journal of Marine Systems, Volume 75, Pages 290-304, http://dx.doi.org/10.1016/j.jmarsys.2008.10.009