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Pushing the frontiers of marine ecological modeling: where are we now and how can we move forward?
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Model-guided quantification of the Three Gorges Dam¡¯s impact on Changjiang estuary¡¯s hydrodynamics and ecosystem
Monday 7th @ 1530-1550, Conference Room 5
Jianzhong Ge* , State Key Laboratory of Estuarine and Coastal Research, East China Normal University
Ricardo Torres, Plymouth Marine Laboratory
Richard Bellerby, State Key Laboratory of Estuarine and Coastal Research, East China Normal University
Lijun Hou, State Key Laboratory of Estuarine and Coastal Research, East China Normal University
Changsheng Chen, School of Marine Science and Technology, University of Massachusetts-Dartmouth
Presenter Email: jzge@sklec.ecnu.edu.cn |
| The Changjiang Estuary is characterized as strong river discharge into the inner shelf of the East China Sea with abundant sediment load, which indicates dominant influences from the Changjiang River. There were increasing constructions of reservoir and dam along the Changjiang River during last several decades, which strongly regulates the river discharge, sediment and nutrients into the Changjiang Estuary, especially during the dry season. The variations of sediment, nutrients, and their influenced ecosystem have been simulated through a comprehensive modeling system, which integrated a multi-scale current-wave-sediment FVCOM model and generic marine biogeochemistry and ecosystem ERSEM model through The Framework for Aquatic Biogeochemical Models (FABM). This model system has successfully revealed the seasonal and decadal variations of sediment, nutrients transport around the inner shelf of the East China Sea. The spring and autumn peaks of phytoplankton growth were correctly captured by simulation. The model system has revealed the hydrodynamic and ecosystem variations under the scenarios of no-Three-Gorges-Dam case (I), Three-Gorges-Dam case (II) and Three-Gorges-Dam (in 2030) case. Additionally, three typical hydrology boundary conditions, high-flow, low-flow and median-flow discharges, are applied on these three scenarios. The results indicate the Three-Gorge Dam has a time-shifting influence on freshwater spreading from the river mouth to outer shelf, showing the most influenced salinity variation occurs from Oct to November in river and mouth, and November in the inner outer shelf. This time-shifting pattern also happens on nutrients dynamics, indicating decrease of nitrate, ammonium and phosphate, and increase of silicate from mouth to shelf. The phytoplankton growth remains low productivity around the turbidity-maximum zone with strong sediment coverage, however, it has small decrease in the inner shelf region. |
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