Introduction. Sedimentary Processes on Estuarine Mudflats: The Example of the Seine and the Authie Estuaries. Quantification of Contaminants. Biomarkers Based upon Biochemical Responses. Biogeochemistry of Metals in Sediments: Development of "Micro-Scale" Analytical Tools and the Use of Indicators of Biological Activities. Organic Contaminants in Coastal and Estuarine Foodwebs. Tolerance in Organisms Chronically Exposed to Estuarine Pollution. Linking Energy Metabolism, Reproduction, Abundance and Structure of Nereis diversicolor Populations. Historical Records of the Nereis diversicolor Population in the Seine Estuary. Ecological Status and Health of the Planktonic Copepod Eurytemora affinis in the Seine Estuary. From Pollution to Altered Fish Physiological Performance; The Case of Flatfish in the Seine Estuary. Diatoms. Foraminifera. Patterns of Abundance, Diversity and Genus Assemblage Structure of Meiofaunal Nematodes in the Seine (Pont de Normandie) and Authie (Authie Port) Estuaries. Dynamic Diagenetic Modelling and the Impact of Biota. Conclusions.