A Historical Perspective on Long-Term Global Biogeochemical Box Models

Biogeochemists have published a constellation of historically linked long-term element cycle box models over the last 50 years. Although these numerical frameworks have tracked a changing subset of elements, isotopes, and processes, many have principally sought to reconstruct the geological history of atmospheric oxygen (pO [[inf]]2[[/inf]] ) and carbon dioxide (pCO [[inf]]2[[/inf]] ). However, the expansive collection of existing models makes it difficult to evaluate new numerical results in the context of the prior work. In this chapter, we begin to address such challenges by overviewing the evolution of long-term element cycle models. Our discussion includes numerical frameworks in the style of Garrels and Lerman (1981), Sundquist (1986), Marshall et al. (1988), and Wallmann (2001), as well as the BLAG, GEOCARB, GEOCARBSULF, COPSE, GEOCARBSULFOR, MAGic, LOSCAR, CANOPS, GEOCLIM, SCION, and GENIE models. The review demonstrates that existing models do not yet robustly represent the temporal evolution of seawater major ion chemistry and concludes with recommendations for future research directions in the box modeling of global element cycles over geological timescales.