A simple biogeochemical model for estuaries with high sediment loads: Application to the Guadalquivir River (SW Iberia)

Estuaries are transition ecosystems connecting land and sea subjected to a large number of external forcings that make estuaries complex and highly variable. Models developed to simulate estuaries use to be also complex and, henceforth, difficult to constrain and parameterize. Here, we propose a simple biogeochemical model of the water column of temperate estuaries based on previously published, well-known models of marine pelagic ecosystems. This model has fewer parameters which are usually well constrained and is more easy to implement and analyze than more complex models. We demonstrate that this model setup could be satisfactorily used to simulate estuarine ecosystems if light availability (constrained by suspended material in the water column) is the main limitation of biological productivity. The proposed model can also be used to assess expected changes in the environmental status of such systems by anthropogenic activity or by climate change.