Scientific Analysis and Applications

The final objective of this project is to develop a more complete understanding of the interplay between physical and biochemical processes that act on petroleum in the ocean and their consequences for deepwater and shelf ecosystems. This will be accomplished through both laboratory studies (to develop improved parameterizations of flocculation processes for the oil-sediment-biogeochemical modeling system) and through numerical experimentation. Some of the questions to be addressed are:

  1. How is the rate of oil deposition via flocculation dependent on the local presence of turbidity in the spill region?
  2. What role do diverse microbial communities that are adapted to utilize substrates at natural oil and methane seeps play in degrading hydrocarbons released during the DwH and other oil spills?
  3. Does colonization of oil-absorbing sinking particles facilitate connectivity between water column hydrocarbon-utilizing microbial communities and similar communities in the benthic realm? Or does sediment resuspension facilitate connectivity between the benthos and water column microbes?

CSOMIO researchers will conduct laboratory flocculation experiments to provide new parameterizations of settling fluxes for the sediment transport model that can incorporate input from the oil model (DCOM), the Fennel water column biogeochemical model, and GENOME. The experiments will provide steady state formulations for floc property populations including diameter, density, and settling velocities. These can be used to characterize floc properties and simplified representations of floc transport. 

The integrated modeling framework will also provide a unique tool for performing numerical experiments to further understand the interplay between the various components of the oil-biogeochemistry system. A control experiment will be completed in which the modeling components are run within the system as-is, with no additional coupling implemented. Twin simulations will be run in which the different coupling computations are implemented, and the model results will be analyzed to determine impacts and sensitivity to the additional processes that are simulated. This exercise will not only yield new information about the roles of different processes in determining the interactions of oil and the marine ecosystem as well as fate of oil from a spill, but will also be used to evaluate the added value achieved by the new coupled system. Similarly, twin experiments will be run that include and exclude natural hydrocarbon seeps and vents that provide a primed microbial community for hydrocarbon degradation. The time and space scales associated with water column hydrocarbon degradation, sedimentation, and sedimentary degradation will be compared between these simulations to better understand potential microbial priming. Additional planned numerical experiments include short-term ensemble simulations that will allow us to generate “cone of uncertainty” type estimates for oil spill trajectory. These simulations will allow us to estimate the effect of hydrodynamic variability on microbial degradation.