Fig. 4: Illustration of the four-box biogeochemical model used in this work.
From: Marine phosphorus and atmospheric oxygen were coupled during the Great Oxidation Event
A Model phosphorus cycle divided into four ocean regions, proximal, distal, surface and deep ocean. Preac dissolved inorganic phosphorus, Porg organic-bound phosphorus (i.e. biomass), PFe iron-bound phosphorus burial, Pauth authigenic P burial (e.g. apatite), Porg organic-bound phosphorus burial. B Model of organic carbon cycle, which is also divided into the same 4 ocean regions. A dissolved inorganic carbon, Corg organic carbon (i.e. biomass) and Corg burial organic carbon burial. C One box inorganic carbon cycle for the ocean and atmosphere; oxidw, carbw and sfw oxidative, carbonate and seafloor weathering, respectively. Locb and mocb land and marine organic carbon burial, respectively. Mccb marine carbonate carbon burial, ocdeg organic carbon degassing, ccdeg carbonate carbon degassing and rgf reducing gas flux. Prod. productivity and Remin. remineralisation. D Model oxygen cycle. Grey arrows in all figures reflect water mass exchange between boxes and transfer of its chemical contents. See ‘methods’ and refs. 62,67. for full description.
