In recent decades, most Spanish Mediterranean agricultural regions have been transformed to meet global food demands and have joined global agricultural production networks: a convergence process that has granted them steady economic growth. In certain cases, however, this transformation has led to a process of ecological degradation. This article focuses on the Torre-Pacheco case, in the Campo de Cartagena region (southeast Spain, Murcia), to reconstruct the events that have led the region to become a global production enclave in agribusiness and to determine the connections between agribusiness transformation and ecological degradation. To this end, a water transfer project is first addressed as the turning point for the local agricultural sector from which the transformation of agribusiness is described regarding land use, technical adaptations, employment/recruitment changes, etc. A documented result of these agribusiness transformations is subsequently presented: a significant contribution to the ecological degradation of the Mar Menor coastal lagoon, whose natural site will remain endangered if 'business as usual' continues.