Abstract: Carbon conversion between different reservoirs in the surface sediments has raised more and more attention from researchers. It mainly includes the dissolved inorganic carbon (DIC) produced by organic matter degradation and anaerobic oxidation of methane (AOM) as well as authigenic carbonate precipitation. In some intensive seepage area, gas bubble migration and dissolution is also an important carbon conversion pathway. In this paper, we summarize the mechanism of organic matter degradation and AOM through numerical modeling. In addition, upon the discussion on the shortages and applicability of each model, we introduced the method of quantification of gas bubble flux into seawater. We finally proposed that more attention be paid to the mechanism of the biogeochemical processes and the model parameters for developing a more generalized model, in order to obtain a more reliable and convincing carbon turnover modeling results.