Simulation of the Egyptian coastal ecosystem functions

• Published in: Proceedings of the Institution of Civil Engineers. Maritime engineering 2004-03, Vol.157 (MA1), p.23-33.
• Main Authors: Hamza, W, Ennet, P, Tamsalu, R
• Format: Article
• Language: English
• ISSN: 1741-7597
• DOI: 10.1680/maen.157.1.23.36774

The mathematical models actually used to solve problems related to water resources and their management are complex in nature due to the fact that they are required to make an effective combination of a range of environmental reactions. These models typically consist of several parts: hydrodynamic, chemical and biological. In addition, atmospheric effects and other factors such as external forces must be considered when simulating existing conditions and in predictions of variations in the ecosystem functions. The aim of this study was to create a tool for operational prediction of the state of the aquatic ecosystem in the Egyptian Mediterranean coastal area. In order to accomplish this task the three-dimensional (3D) hydrodynamic-ecosystem FINEST model has been implemented over the entire Egyptian Mediterranean coastal area, and the validity of this model for the coastal area was tested. The coupled 3D hydro-ecosystem FINEST model is characterised by a double s coordinate system, which divides the marine basin into two parts: an upper layer and a lower stratified layer. The ecosystem part of the model consists of the plankton community, inorganic nutrients, organic nutrients and detritus sub-models. The plankton community food web comprises four triplets where each triplet is formed by one heterotrophic predator-grazer and zooplankton prey, and one phytoplankton according to the class size. In the last (fourth) triplet the zooplankton prey is replaced by bacterioplankton. The application of the coupled 3D model on the ecosystem of the Egyptian Mediterranean coastal area demonstrates its suitability as an operational management system able to simulate external forcing factors (e.g. nutrients discharge, land runoffs, coastal meteorological forces, etc.) and predict the effects of these forces on the ecosystem components. A short-term validation test of specific parameters in the model has shown its sensitivity toward variations in the ecosystem due to external forcing factors. The results obtained from this test and presented here are preliminary ones however; further implementations of the model are in progress and will be published elsewhere with mathematical details of the model equations.