title: Using natural abundance radiocarbon to trace the flux of petrocarbon to the seafloor following the Deepwater Horizon oil spill.
abstract: In 2010, the Deepwater Horizon accident released 4.6–6.0 × 10(11) grams or 4.1 to 4.6 million barrels of fossil petroleum derived carbon (petrocarbon) as oil into the Gulf of Mexico. Natural abundance radiocarbon measurements on surface sediment organic matter in a 2.4 × 10(10) m(2) deep-water region surrounding the spill site indicate the deposition of a fossil-carbon containing layer that included 1.6 to 2.6 × 10(10) grams of oil-derived carbon. This quantity represents between 0.5 to 9.1% of the released petrocarbon, with a best estimate of 3.0–4.9%. These values may be lower limit estimates of the fraction of the oil that was deposited on the seafloor because they focus on a limited mostly deep-water area of the Gulf, include a conservative estimate of thickness of the depositional layer, and use an average background or prespill radiocarbon value for sedimentary organic carbon that produces a conservative value. A similar approach using hopane tracer estimated that 4–31% of 2 million barrels of oil that stayed in the deep sea settled on the bottom. Converting that to a percentage of the total oil that entered into the environment (to which we normalized our estimate) converts this range to 1.8 to 14.4%. Although extrapolated over a larger area, our independent estimate produced similar values.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Chanton
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhao
authors.forename: Brad E
authors.initials: BE
authors.lastname: Rosenheim
authors.forename: Samantha
authors.initials: S
authors.lastname: Joye
authors.forename: Samantha
authors.initials: S
authors.lastname: Bosman
authors.forename: Charlotte
authors.initials: C
authors.lastname: Brunner
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Yeager
authors.forename: Arne R
authors.initials: AR
authors.lastname: Diercks
authors.forename: David
authors.initials: D
authors.lastname: Hollander
mesh_terms: D002244:Carbon / Q000032:analysis; D002250:Carbon Radioisotopes / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D005431:Florida; D005843:Geography; D019015:Geologic Sediments / Q000032:analysis*; D060851:Gulf of America; D008922:Mississippi; D059392:Petroleum Pollution / Q000032:analysis*; D045483:Rivers; D014867:Water / Q000737:chemistry*; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D002250:Carbon Radioisotopes; D014873:Water Pollutants; D014867:Water; D002244:Carbon