Polymetallic nodules, containing up to 30% of manganese by weight, are found naturally and in abundance on the seabed in some areas in the Pacic ocean and the Indian ocean. Technical activities for the harvesting of poly-metallic nodules over the seabed likely penetrate into the top layer (about 10 cm) of the ocean floor and re-suspend the sediment into the ambient ocean water. Sediment spreading in the ocean is unavoidable and definitely affects the ambient area near the harvesting site. It is known that concentration of suspended particulates has certain impacts to aqueous lives in the ocean bottom regions. Small-scale trials for the polymetallic-nodule collection, performed in the Clarion-Clipperton Zone in the Pacic Ocean since 1970 to evaluate possible impacts of the actual activities to the benthic community, reveal that the fauna density and the diversity recover one year later but some very minor groups only return slowly after one decade. Aims of the project are:
- Provide estimates of sediment disturbance generated by the harvester to be used as inputs to ocean-scale sediment dispersion simulations,
- To assess spreading of sediment in the ocean due to seabed technical activities for Environmental Impact Assessment in taking into account the polydispersed and cohesive nature of the sediment,
- Make use of experimental validations: seabed sediment characterisation as a yield stress material, models of sediment using available bentonite/kaoline clays, cross-correlation of numerical model against experiments, especially for harvester-generated disturbance.
3D MPI-Parallel SPH simulation for sediment dispersion from a stationary sediment source (60 cores)
3D MPI-Parallel SPH simulation for sediment dispersion from a moving sediment source (60 cores)
Selected publications:
Nhan Phan-Thien's Research & Innovation 