Summary:
Marshes represent perhaps the most critical habitat to maintaining the ecological and economic health of Florida's Gulf Coast. They are also among the most sensitive to damage from Deepwater Horizon (DH) oil contamination. Paradoxically, more damage may be done by misguided efforts at oil removal from the marsh than by the oil itself. Other options such as microbial treatment carry large costs and fertilization can lead to eutrophication in some cases. To guide the remediation decision to be made in regards to response to DH-oil contamination of Gulf Coast marshes, the proposed research will study the fate of DH oil and its associated ecological consequences under three possible response strategies that we consider cost and goal-effective for Gulf Coast marshes.
In addition to monitoring natural biodegradation, DH oil (no treatment) which is expected to be relatively rapid for less contaminated marshes given the high local temperatures, and active microbial communities, we will apply two novel treatments:
- Mechanical aeration of sediments as it is oxygen concentration that is the most likely limiter of natural oil degradation.
- Biochar additions to the sediments as this agent is a natural sorbent (pyrolyzed organic materials such as agricultural residues) that may minimize ecological damage while maintaining or enhancing oil degradation.
We will fully cross these treatments for a 2 x 2 design and establish replicate experiments in ecologically similar marshes on the Florida panhandle with no, low, and high amounts of DH oil contamination (2 marshes will be chosen for each level). Oil degradation will b e monitored over a year using bulk and molecular organic geochemical tools and ecological health will be simultaneously monitored using plan, animal and biogeochemical measurements. This work will provide, not only important chemical and ecological information in regards to this particular crisis, but will improve our overall understanding of oil's effect on marsh ecosystems, how this interaction changes with time and oil degradation, the chemical components of DH oil in the present and future coastal marsh, and test one under-studied and one never before studied remediation option well-suited for use in sensitive marsh systems.