The Mar Menor is one of the largest hypersaline coastal lagoons of the Mediterranean Area, measuring about 170 km2 with a mean depth of 2.5 m. It is separated from the Mediterranean Sea by a narrow sandy coastal barrier and is surrounded by the Campo de Cartagena, one of the most intensive agricultural zones of Spain. This fragile ecosystem suffers intense human pressure, such as excess nutrient and sediment inputs from agriculture and abandoned mining activities, respectively, as well as decreases in salinity. The waters of the Mar Menor had become a “clinically” dying ecosystem and many ecologists called the disaster Europe’s worst environmental catastrophe. Many knew that the agony had begun many years ago.