Box models of volatile cycles over the entire Phanerozoic
Three stand-alone geochemical box models have been developed to simulate globally coupled biogeochemical cycles. These models reflect the evolution of the participating biotic and abiotic constituents in marine and terrestrial environments, including the lower atmosphere. The single models focus on the calculation of: 1) the chemical evolution of seawater, 2) the atmospheric methane concentration, and 3) the concentration of oxygen in surface and deep ocean water over the entire Phanerozoic (570 Ma). The models are driven by geological and evolutionary forcings and are controlled by proxy data. Internal feedback is provided by model outputs serving as input to other model components. The Phanerozoic biogeochemical evolution of seawater (dissolved inorganic carbon, alkalinity, nutrients, and oxygen), its isotope sulfur and carbon composition, as well as the atmospheric partial pressures of oxygen (pO2), carbon dioxide (pCO2), and methane (pCH4) are calculated by standard runs of the individual models.