Tracer Methods in Marine Sediment Dynamics

GAO Shu

The present contribution is concerned with the application of tracer methods to marine sediment dynamics, in terms of material source identification, sediment transport rate calculations and the problem of a universal theoretical framework. For the tracing of material sources, mixing models that are originally established for river basin systems should be modified to fit marine environments; in particular, changes in the fingerprinting particles during transport must be considered. In the research field of sediment transport rate determination, artificial tracers have been used, on the basis of the spatial integration method (SIM), the time integration method (TIM), or the continuous injection method (CIM), with the SIM being the most popular. In the application of these methods it is crucial to define the centroid movement and the depth of disturbance. In the case of natural tracers, these methods are no longer applicable because the centroid movement cannot be defined. Nevertheless, in some circumstances, natural tracers can provide information on transport, on the basis of a mathematical model. Further investigations are required in the future to establish a universal theoretical framework for both artificial and natural tracers for sediment transport studies, in which solutions must be found to the problems associated with the differential dynamic behaviors of the tracer and the bulk sediment, deposition rates and the depth of disturbance as functions of the temporal scale, and sediment dispersive processes.

Ministry of Education Key Laboratory for Coast and Island Development, Nanjing University, Nanjing 210093

Received Date: 2002-09-20

Rev Recd Date: 2003-01-10

Publish Date: 2003-03-10

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Abstract: The present contribution is concerned with the application of tracer methods to marine sediment dynamics, in terms of material source identification, sediment transport rate calculations and the problem of a universal theoretical framework. For the tracing of material sources, mixing models that are originally established for river basin systems should be modified to fit marine environments; in particular, changes in the fingerprinting particles during transport must be considered. In the research field of sediment transport rate determination, artificial tracers have been used, on the basis of the spatial integration method (SIM), the time integration method (TIM), or the continuous injection method (CIM), with the SIM being the most popular. In the application of these methods it is crucial to define the centroid movement and the depth of disturbance. In the case of natural tracers, these methods are no longer applicable because the centroid movement cannot be defined. Nevertheless, in some circumstances, natural tracers can provide information on transport, on the basis of a mathematical model. Further investigations are required in the future to establish a universal theoretical framework for both artificial and natural tracers for sediment transport studies, in which solutions must be found to the problems associated with the differential dynamic behaviors of the tracer and the bulk sediment, deposition rates and the depth of disturbance as functions of the temporal scale, and sediment dispersive processes.

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Tracer Methods in Marine Sediment Dynamics

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