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Coupled hydrodynamic ecosystem model (ECOSMO)

Coupled Hydrodynamic Ecosystem Model (ECOSMO). The model is computationally more efficient and at an intermediate level of complexity allowing the testing of hypotheses regarding the effect sof climate change on the functioning of marine ecosystems.

- Scientific Result Description:

A non-linear 3-d baroclinic model using a turbulent eddy viscosity calculated as a function of turbulent eddy kinetic energy HAMSOM was developed and implemented. The prognostic model variables of relevance are temperature, salinity, water transports, sea surface elevation, turbulent vertical eddy viscosity and diffusivity, and the turbulent sea surface fluxes (evaporation and latent heat, sensible heat flux and wind stress). HAMSOM model coding, including nesting, and model results provided the basis for further developments of a coupled biological-physical model (ECOSystem Model).

Lagrangian ECOSMO, as well in nested version) and a coupled on or off-line IBM particle tracking model (part of ECOSMO) The lagranian particle tracking model with possible individual based motion was used to study local aggregation effects. The model was applied for the nested fine scale model HAMSOM-NEST around the Dogger Bank region

An Eulerian aggregated NPZD model was developed and coupled to the hydrodynamic/sea ice model HAMSOM to study the local production effects at frontal locations. The ecosystem module of ECOSMO has been developed to simulate different macro-nutrient limitation processes. ECOSMO includes interactions between 12 state variables.

The basis of model is 3 nutrient cycles, the nitrogen cycle, the phosphorus cycle and the silicate cycle, covering the main macro nutrients limiting phytoplankton production in shelf seas. The specific nutrients included in the ecosystem block are ammonium (NH4), nitrite (NO2), nitrate (NO3), phosphate (PO4), silicate (SiO2); and biogenic opal. Other state variables are detritus (D) and oxygen (O2). ECOSMO uses these nutrients to simulate the dynamics of two functional groups of phytoplankton diatoms (Pd) and flagellates (Pf) with the dynamics of each group simulated based on their respective nutrient, light and physiological characteristics are used.

Based on the dynamics of the phytoplankton components two zooplankton functional groups are simulated these being micro-zooplankton (Zs) and macro-zooplankton (Zl) with the dynamics based on feeding behaviour. Accounting in the model is based on the concept of Redfield stoichiometry with interactions based on the Redfield ratio C:N:P=1:16:106 using as a coin of transfer carbon units mg C m-1

- Dissemination:
HAMSOM and ECOSMO have resulted in the submission or publication of 12 articles for Internationally Reviewed Journals, 14 presentations to international audiences as well. Furthermore the results and interrelationships with exploited fish populations have been utilized and or presented at:
-- ICES North Sea MSVPA working group meetings.
-- International Herring Acoustic Survey Meeting.

- Current status and use:
Access to the coupled model is possible based on communication with the developer.

- Expected benefits:
The Model allows resolution of historic distribution of hydrograph properties in the North Sea and Baltic for comparison with fisheries surveys, the distribution o f fisheries activities, as well as enabling the scenario testing of the effects of climatic processes on the dynamics of the North Sea and Baltic ecosystems and their exploited fish populations.

Informations connexes

Reported by

University of Hamburg
Olbersweg 24
22767 Hamburg
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