MORGAN FRANKLIN Degrees: I have a B.S. in Mathematics from UW-Madison. I am currently working on a Master’s degree in Atmospheric and Oceanic Sciences at UW-Madison. Office: Room 835 AOSS, (608) 890-0119

I am currently adding a silicon cycle parameterization to the biogeochemical model OCMIP (Ocean Carbon-Cycle Model Intercomparison Project) within POP (Parallel Ocean Program), an active ocean model within CCSM3 from NCAR. The silicon cycle will be coupled with the carbon cycle within the model. This should increase the accuracy of the carbon cycle parameterization.

This improved parameterization could prove to be imperative for paleoclimate scenarios, as the phytoplankton that control these biogeochemical cycles are integral components of climate feedback loops. It is likely that diatoms (siliceous phytoplankton) became less abundant during the PETM. This could have served as a positive feedback for warming during this hyperthermal event.

Literature:

In my model, biogenic silica production is based on a parameterization in the MUDS model by Archer et al. (2002), which follows work by Maier-Reimer (1993). Sinking and dissolution is based on Gnanadesikan (1999). Coupling of the carbon cycle to silica production will be based on Heinze et al. (1999).

Gnanadesikan, A. (1999). A global model of silicon cycling: Sensitivity to eddy parameterization and dissolution. Global Biogeochemical Cycles, 13(1), 199-220.

Archer, D. E., Morford, J. L., & Emerson, S. R. (2002). A model of suboxic sedimentary diagenesis suitable for automatic tuning and gridded global domains. Global Biogeochemical Cycles, 16(1), doi:10.1029/2000GB001288.

Heinze, C., Maier-Reimer, E., Winguth, A. M. E., Archer, D. (1999). A global oceanic sediment model for long-term climate studies. Global Biogeochemical Cycles, 13(1), 221-250.

Maier-Reimer, E. (1993). Geochemical cycles in an ocean general circulation model. preindustrial tracer distributions. Global Biogeochemical Cycles, 7(3), 645-677.

SI Diagram