Phosphorus spatial distribution and mass balance in the Itaipu lagoon (Rio de Janeiro, Brazil)

The degradation of tropical coastal lagoon systems in urban areas the least developed countries has been associated with an increase impermeable and poor domestic sewage treatment, increasing land-based runoff nutrients suspended solids from catchments. This study aimed to assess biogeochemical changes caused by human interventions through analysis spatial distribution sedimentary phosphorus (P) its mass balance Itaipu lagoon, located on east coast state Rio de Janeiro. Human intervention system severe imbalances cycles over past decades. Watercourses have channeled normalize hydrological regime hydraulic energy, improving sediment transport capacity. In this context, basin into buried amount sediment. Recently, a regional storm events series landslides floods, which reported as possible consequences global climate change. recent decades, synergy between river channeling increased TP loads, accelerating settling changing P surface sediments. accelerated siltation accumulation organic matter, leading some cases anoxia. undergone strong eutrophication, trophic meso- hypertrophic less than 30 years, even though loads are not high other lagoons. Our findings confirm that impacts nutrient turn disrupt cycles, compromising water resources. leads collapse ecosystem services, another step towards degrading planetary boundaries.