2024 Volume 47 Issue 5 Pages 151-161
At present, many efforts are being made to ensure the biodiversity and productivity of the marine ecosystems in Harima Nada, the Seto Inland Sea, by increasing the land-derived load of nutrients, such as total nitrogen (TN) into the sea. In this study, a food chain model was used to predict the effects of changes in the input of land-derived TN on the marine TN concentration and the Harima Nada ecosystems’ production of phytoplankton, zooplankton, and higher-trophic-level organisms. The model’s ecosystem parameters were estimated stochastically by the Monte Carlo method. The model successfully reproduced the TN concentration and the biomass production in both northern-coastal and central-southern area with different environmental characteristics. By incrementing land-derived TN load 10 times of the 2010s by the model, the estimation of TN concentration in marine waters increases by up to 1.9 times in the northern-coastal area and 1.3 times in the central-southern area. Additionally, there is an increase in the biomass of piscivorous species (highest ecosystem production level) of 1.2 times for the entire Harima Nada.
