Nutrient flow modeling as a tool for investigating self-regulating mechanisms and productivity in eutrophication...

Coastal lagoon ecosystems have high biological and fishery production and important biological and socio-economic values. At the same time, they are vulnerable to the increasingly intense input of nutrients from natural, agricultural and urban sources, making them susceptible to eutrophication and dystrophic crises. The Mar Menor, one of the largest coastal lagoons in the Mediterranean, has maintained its exceptional combination of high biological production and high environmental quality for many years, making it an important social and economic driver. However, changes in agricultural practices and inappropriate management over the last three decades have initiated a process of eutrophication that, after 20 years of self-regulation by the ecosystem, has led to a eutrophication crisis that threatens the ecological integrity of the lagoon. The high homeostatic capacity and resilience of the ecosystem to nutrient inputs raises the question of whether it is possible to know the carrying capacity of the system and what self-regulatory mechanisms allow it to maintain ecological integrity and productivity despite nutrient inputs. We model the N/P balance in the lagoon to analyse the nutrient loads that lead to ecosystem collapse and water quality loss, and to understand the mechanisms that enable the ecosystem's homeostatic capacity and its recovery after eutrophic crises and system failures.