Summary:
The Deep Horizon spill in the northern Gulf of Mexico has resulted in the contamination of over 200 miles of shoreline and over 80 acres of inland marsh in Louisiana at the date of this proposal. Our group has investigated biodegradation of crude oil in marshes and the geochemical factors that impact rates of recovery and plan to apply our techniques to understand recovery of marshes from this spill. Bioremediation is an emerging technology that has the potential to accelerate crude oil degradation in marshes since it builds upon the natural biodegradation processes that occur in the marsh. Deep Horizon oil is reaching the LA coast as an emulsion and is oiling the marsh in a unique geometry. We can find no studies that examined the fate of emulsified oil in marshes and our proposed studies are to extend our research to these conditions.
Our research plan for this study would test three hypotheses:
1. N addition will increase rates of degradation of DH emulsions. Greenhouse core and microcosm studies will assess the impact of N additions on rates of biodegradation of DH emulsions. These will be complemented by measurements at field sites of background N concentrations and oil degradation rates
2. Geochemical conditions that help break the emulsion will accelerate marsh recovery. Emulsion stability studies will be conducted on Spartina stems to evaluate the formation of oil:mineral aggregates and iron reduction as processes that might break emulsions
3. Anaerobic microbial degradation processes under sulfate-reducing conditions degrade alkane and PAH DH crude oil components. Microcosm studies under sulfate reducing conditions will be performed using DH oil to assess capabilities of existing sulfate reducing populations to contribute to natural recovery of the marshes
A series of analytical methods will be used to assess biodegradation induding GC-MS analysis of crude oil components referenced to poorly biodegradable biomarkers such as hopane and a stable isotope approach developed by the PI's lab that can measure crude oil mineralization directly.
To effectively assess the recovery of our marshes and associated tidal passes and shallow bays, we must take a risk-based approach which looks at both the concentrations of hydrocarbons (and the fate processes which impact those concentrations) and the effects of these hydrocarbons on the biota in the marshes and sediments of the tidal passes. We have linkages with 3 groups: Dr. Allen Burton, Director of NOAA's Cooperative Institute for Limnology & Ecosystems Research located at the University of Michigan and investigators at The Institute of Environmental and Human Health (TIEHH) and Civil & Environmental Engineering at Texas Tech University. These investigators will travel to LSU, present seminars, interact with graduate students and participate in field sampling. This will build capabilities and linkages for further collaborative proposals with LSU.