Date of Award
Master of Science (MS)
Molecular and Cellular Biology and Pathobiology
Marine Biomedical and Environmental Sciences
College of Graduate Studies
Pamela Jo Morris
Peter D. R. Moeller
Thomas J. McDonald
Before the Pearl Harbor attack on December 7, 1941, the USS Arizona's 4,630-ton fuel tanks have been filled with Bunker C fuel oil, a No. 6 fuel oil. Currently the ship remains in the place where it sank as the USS Arizona memorial site in Pearl Harbor, HI. A significant amount of oil remains in the ship today and 1-2 L is leaking per day from several different locations (Murphy and Russell, personal communication). The focus of this study was to conduct a preliminary environmental assessment of the oil leaking from the USS Arizona, and to determine if aerobic microbial degradation processes are influencing oil composition. In 2000 and 2001, oil and sediment samples were taken from the ship and adjacent areas to examine the extent of oil weathering as well as the microbial degradability of the leaking oil. The first objective of this study was to chemically characterize oil leaking from different locations of the USS Arizona. Gas chromatographic analysis indicated that oil leaking from the stern starboard hatches had fewer n-alkanes and appeared weathered in comparison to oil leaking from barbette no. 4. Biomarker analysis of leaking oil showed no difference between hopanes (m/z=191) and steranes (m/z=217) found in oil leaking from different locations, suggesting that biomarker profiles in oil leaking form the USS Arizona are not being influenced by weathering processes inside the ship. The second objective was to assess the oil composition in sediments collected from on top of the ship as well as in sediments adjacent to the ship. Following continuous soxhlet extraction, gravimetric analysis suggested low amounts of extractable materials ranging from 0.99±0.61 to 2.59±0.11 mg of solvent extractable material per gram of sediment. Gas chromatography coupled to flame ionization (GC-FID) detection suggested the presence of n-alkanes in sediments. Furthermore, a predominant and ubiquitous peak was found in all sediment extracts and indentified by mass spectrometry as butylated hydroxytoluene (BHT) (m/z 205.3). PAH analysis of sediment extracts indicated lower molecular weight PAHs (e.g., naphthalenes) were below the detection limit although higher molecular weight PAHs (.e.g., chrysene) were still present. The third objective was to determine the degradability of Bunker C fuel oil leaking from the ship by microorganisms enriched from Pearl Harbor sediments, and to determine if the enriched microbial community was capable of influencing biomarker profiles present in the oil. Aerobic microbial enrichment cultures were initiated using sediments collected from 8 ship locations, and oil leaking from the ship was used as the sole source of carbon. Following the third monthly transfer of these enrichments, gravimetric analysis of oil extracted from enrichment cultures indicated an average loss of 31.03±4.58%. Analysis by G-FID demonstrated extensive degradation of the n-alkanes and branched alkanes, in comparison to uninoculated controls. Mass spectrometry also indicated degradation of PAHs. For example the ratio of total PAHs to the conserved biomarker C3017a(H),21B(H)-hopane was 15.32±4.30 for the uninoculated control in comparison to USS Arizona aerobic enrichment culture 00-002 which had a ratio of 1.66±0.14. Denaturing gradient gel elecrophoresis analysis of enrichment cultures revealed multiple banding patterns with an average of 12 bands per enrichment culture. Biomarker analysis indicated degradation of C28-C29 tricylic terpanes along with degradation of C27-steranes. Oil leaking from the ship shows different amounts of weathering. Oil leaking from the hatches near barbete no. 4 is less weathered than oil leaking from the stern starboard portholes. This suggests oil residence times within the ship are different. Materials extracted from sediments contained n-alkanes along with BHT and high molecular weight PAHs. BIomarkers from the ship and the sediment extracted materials have similar profiles and contain same compounds, such as C2017a(H),21B(H)-hopane, 18a-oleanane, and tricyclic terpanes. USS Arizona aerobic enrichment cultures degraded the n-alkanes, branched alkanes, PAHs and biomarkers (C28-C29 tricyclic terpanes and C27-steranes). Overall, this study will contribute to the USS Arizona memorial site by providing background information useful for environmental considerations, such as what is the composition of the oil leaking from the ship and what compounds are present in the sediments. Furthermore, the aerobic degradation study suggests the oil leaking from the ship is degradable under laboratory conditions.
Graham, Amanda M., "The USS Arizona and Bunker C Fuel Oil: an Environmental Study" (2003). MUSC Theses and Dissertations. 753.
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