Revisited ecosystem model (MODECOGeL) of the Ligurian Sea: seasonal and interannual variability due to atmospheric forcing
Lacroix, G.; Grégoire, M. (2002). Revisited ecosystem model (MODECOGeL) of the Ligurian Sea: seasonal and interannual variability due to atmospheric forcing. J. Mar. Syst. 37(4): 229-258. dx.doi.org/10.1016/s0924-7963(02)00190-2
In: Journal of Marine Systems. Elsevier: Tokyo; Oxford; New York; Amsterdam. ISSN 0924-7963; e-ISSN 1879-1573, more
|  |
| Keywords |
Atmospheric forcing
Biological production > Primary production
Cycles > Chemical cycles > Geochemical cycle > Biogeochemical cycle > Nutrient cycles > Nitrogen cycle
Data > Meteorological data
Ecosystems
Energy transfer > Heat transfer > Heat flow
Environmental effects
Microorganisms > Bacteria
Modelling
Population characteristics > Biomass
Temporal variations > Periodic variations > Annual variations
Temporal variations > Periodic variations > Seasonal variations
MED, Ligurian Sea [Marine Regions]
Marine/Coastal |
| Author keywords |
coupled physical-biological model; NW Mediterranean Sea; ecosystem dynamics; seasonal and interannual variability |
| Abstract |
A one-dimensional coupled hydrodynamical-biological model, MODèle d'ECOsystème du G.H.E.R. et du L.O.V. (MODECOGeL), of the water column is developed and applied to the Ligurian Sea (North Western Mediterranean). It is an extended and improved version of the model presented by Lacroix and Nival [J. Mar. Syst. 16 (1998) 23]. The hydrodynamic model is a 1D version of the 3D turbulent closure G.H.E.R. model, which takes into account momentum and heat surface fluxes computed from a real meteorological data set. The ecosystem model is defined by a nitrogen cycle described by 12 biological state variables including several plankton size classes and an explicit description of the bacterial loop. One data set coming from the FRONTAL missions is used to initialise and validate the model. To assess the impact of the interannual variability of the meteorological conditions on the ecosystem dynamics, the coupled model is run with 4-year real meteorological conditions (October 1984-September 1988). The model estimated percentages of the interannual variability of the annual mean biomass of phytoplankton, zooplankton and bacteria respectively of 31.0%, 16.2% and 16.3%. The contribution of the zooplankton related to the total plankton biomass (phytoplankton, zooplankton and bacteria) has been found to be the most sensitive to the meteorological conditions variations (21%), followed by the phytoplankton (12%) and finally, by the bacteria (5%). The model estimated percentages of interannual variability of the annual gross primary production, the annual mean f-ratio and the annual bacterial production respectively of 27.9%, 18.5% and 13.4% although the interannual variability of the real winds conditions is only of 11.3%. Due to the more windy and less sunny conditions prevailing during the years "1985-1986" and "1986-1987", the annual primary production was found higher than during the years "1984-1985" and "1987-1988". The bacterial production is always greater than the primary production, showing the importance of the bacteria in such an oligotrophic environment. On a seasonal scale, the highest interannual variability of the primary production and the f-ratio is found in spring like for the wind intensity. |
|
