CostAeffective ecological indicators can be provided on a large spatial scale by ocean color (OC) remote sensing (RS) observations and used for an ecosystemAbased management. For this purpose, sensors such as SeaWiFS or MODIS managed by NASA, or MERIS and OLCI sensors on board of European Space Agency (ESA) satellites, have been designed. However, the validation of satellite products with regional characteristics is a nonAreplaceable requirement to profit from these sensors capabilities. Within this framework, this proposal intends to test and validate RS algorithms and satellite products to study and monitor sediment dynamics in two large estuaries like the Río de la Plata (Argentina) and Tagus (Portugal). The applicability of a general turbidity algorithm in the turbid waters of Río de la Plata and Tagus rivers will be tested and the relationship between turbidity and suspended particulate matter (SPM) concentration will be assessed and compared in order to generate regional SPM maps.