The PI requests MRI RAPID funding to acquire a Gas Chromatograph coupled to a Mass Spectrometer detector (GC-MS) and an Accelerated Separation Extraction (ASE) system. The instruments will be used to extract and characterize the organic composition of sediment and particulate organic carbon (POC) samples impacted by the massive oil spill in the Gulf of Mexico. Particular attention will be given to petroleum biomarkers (e.g., hopanes, steranes, terpanes) and polycyclic aromatic hydrocarbons (PAHs), which are predominant components of oils and are expected to be found at increased quantities in the area affected by the spill. GC-MS analysis of a several month-long time series of sediment and POC samples will be used to identify and quantify transformations of the oil-derived organic matter with time and distance from the spill site. The PI will compare the composition and degradation products of oil-impacted samples throughout the water column, from the surface to the subsurface plumes observed in the Gulf.
Broader Impacts
The analyses proposed here will benefit the Gulf oil spill efforts by rapidly characterizing the oil degradation products in the spill region, quantifying their differences throughout the water column as a function of different degradation process, and identifying their assimilation by the bacteria community. This will provide new insights in the biogeochemical response to a massive oil spill that will aid to informed decision making in the current response effort in the Gulf of Mexico. In the long term, the acquisition of an GC-MS and extraction system will complement courses offered by the Marine Science department through the implementation of laboratory sessions by the PI. Instruments will be made available for use by other researchers at UGA. A graduate student will work in collaboration with the PI on the analyses of Gulf of Mexico samples using both instruments.
Intellectual Merit: This award supported the acquisition of a Gas Chromatography coupled to a Mass Spectrometer detector (GC-MS) and an Accelerated Separation Extraction (ASE) system to extract organic compounds and characterize the molecular organic composition of samples collected in the Gulf of Mexico after the Deepwater Horizon oil spill in 2010. The major focus is the analysis of components commonly found in oils, namely petroleum biomarkers (e.g., hopanes, steranes, terpanes), unresolved complex mixture (UCM), and polycyclic aromatic hydrocarbons (PAHs), and the identification and quantification of their transformation products with time and distance from the spill site. Since their acquisition, both instruments (housed at the Department of Marine Sciences, University of Georgia) have been used to analyze sediment and particulate organic carbon samples collected during several research cruises to the Gulf of Mexico in collaboration with scientists from University of Georgia and other institutions. Samples were collected in May 2010 (~ 20 days after the Macondo well blow out), September 2010, December 2010, and more recently, in July 2011 in an effort to understand the effects of the oil spill to the biogeochemistry of the impacted area. The analyses revealed that some fraction of the oil released settled to the seafloor in a substantial pulse that occurred between June and September 2010. Concentrations of petroleum biomarkers and unresolved complex mixture in seafloor samples were much higher (by a factor of 2-7) in September 2010 than in May 2010. Polycyclic aromatic hydrocarbons were more abundant to the northwest of the wellhead in September 2010. These results are consistent with the idea that much of the oil released was deposited subsequently to the seafloor. Observations from more recent cruises are now being analyzed to track the current effects of the spill on the Gulf biogeochemistry. Broader Impacts: The acquisition of a GC-MS and an ASE system allowed for the automated extraction and characterization of organic compounds in various environmental samples by researchers at the University of Georgia. Findings from this study were presented in national meetings, as well as in symposium and seminars targeting the general public, high school and non science major students. A publication describing the results is currently in preparation. The work is now being expanded due to a recent award to study oil inputs and biogeochemical responses in the Gulf of Mexico. As part of that effort, graduate students will be trained in the identification of molecular biomarkers using the GC-MS acquired as part of this grant.
