The OMEXDIA model

This model is based on the original OMEXDIA model (Soetaert et al., 2006), but has been extended to consider

• Silicate ( based on Van Cappelen et al. 2000)
• Phosphate ( based on Slomp et al. al. 1999)
• Non-local bioirrigation ( based on Aller et al. al. 1989)

Model Variables

Pore water Solutes

in mmol/m3 of liquid.

Variable name	Description
O2	Oxygen
NO3	Nitrate + Nitrite
NH3	Ammonium
DIC	Dissolved Inorganic Carbon
PO4	Phosphate
SiO	Silicate
ODU	Oxygen Demanding Units ( sum of reduced species, e.g. typically Fe, Mn, H2S )

Fluxes at the sediment water interface are defined for each solute state variable.

Solid phase

in mmol/m3 of solid.

Variable name	Description
FDET	Fast decaying organic carbon
SDET	Slow decaying organic carbon
SiDET	Silicious detritus (Opal)
FeP	Iron-bound phosphate
CaP	Authigenic phosphate (e.g. Apatite)

References

• Soetaert, Karline, Peter MJ Herman, and Jack J. Middelburg. "A model of early diagenetic processes from the shelf to abyssal depths." Geochimica et Cosmochimica Acta 60.6 (1996): 1019-1040.

• Slomp, C. P., Malschaert, J. F. P., & Van Raaphorst, W. (1998). The role of adsorption in sediment‐water exchange of phosphate in North Sea continental margin sediments. Limnology and Oceanography, 43(5), 832-846. Chicago

• Van Cappellen, P., & Qiu, L. (1997). Biogenic silica dissolution in sediments of the Southern Ocean. II. Kinetics. Deep Sea Research Part II: Topical Studies in Oceanography, 44(5), 1129-1149.

• Aller, R. C., & Aller, J. Y. (1998). The effect of biogenic irrigation intensity and solute exchange on diagenetic reaction rates in marine sediments. Journal of Marine Research, 56(4), 905-936. Chicago