Geochemistry of dissolved carbon in pelagic and benthic ecosystems

The dynamics of the aquatic ecosystem requires a thorough knowledge of the chemical and physical parameters in both the water column and the sediment. The constitutive equations of the former subsystem solve diffusion and transport processes in three-dimensional domains; the latter is described by one-dimensional and nonlinear differential equations whose solution strongly depends on slower diffusion parameters. An evolution method, CO2-Geo, which minimises the squared deviation between the exact evolution and the consistent prediction with the transformation method, is developed and verified to estimate the single-layer evolution and the three-layer sediment description based on the diffusion parameters in the porewater. The method is generic and is extended here to the trophic behaviour of carbon dioxide and methane.