Effect of extreme rainfall events in the Mar Menor lagoon (SE, Spain): the use of a smartbuoy for environmental monitoring

Extreme climate events, now more frequent, are defined by the IPCC as occurrences outside typical weather ranges. Extreme rainfall, for instance, can lead to excessive freshwater inflow into saltwater environments, disrupting ecosystems like coastal lagoons. The Mar Menor lagoon in Spain faces issues like eutrophication and habitat loss due to changing water conditions. Monitoring water quality is crucial for managing these risks. While traditional sampling methods are valuable, realtime data from buoys enables quicker responses. This study focuses on data from sampling stations and a smartbuoy in the Mar Menor lagoon following rainfall events on October 6th and 10th, 2022. The goal was to assess how long the ecosystem took to recover. Results showed that the southern part of the lagoon had a delayed recovery compared to the northern region, with significant impacts on salinity, turbidity, and oxygen levels. Immediately after the rainfall, lower surface salinity was observed in the southern lagoon due to freshwater influx, while the northern region remained stable. Freshwater also affected bottom salinity along the western shore. By October 19th, salinity in the lagoon’s center had increased but had not returned to pre-rainfall levels, with lower salinity still present in the southern region. Turbidity also increased along the western and southern shores due to runoff carrying nutrients and sediments, potentially disrupting local ecosystems. The continuous data from the smartbuoy offered detailed insights into hydrological changes, salinity, turbidity, and oxygen variations. This real-time data is essential for effective environmental management and conservation efforts in the lagoon ecosystem.