title: Composition and depth distribution of hydrocarbons in Barataria Bay marsh sediments after the Deepwater Horizon oil spill.
abstract: In 2010, an estimate 4.1 million barrels of oil were accidentally released into the Gulf of Mexico (GoM) during the Deepwater Horizon (DWH) Oil Spill. One and a half years after this incident, a set of subtidal and intertidal marsh sediment cores were collected from five stations in Barataria Bay, Louisiana, USA, and analyzed to determine the spatial and vertical distributions and source of hydrocarbon residues based on their chemical composition. An archived core, collected before the DWH oil spill from the same area, was also analyzed to assess the pre-spill hydrocarbon distribution in the area. Analyses of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and stable carbon isotope showed that the distribution of petroleum hydrocarbons in Barataria Bay was patchy and limited in areal extent. Significant TPH and ΣPAH concentrations (77,399 μg/g and 219,065 ng/g, respectively) were detected in the surface sediments of one core (i.e., core A) to a depth of 9 cm. Based on a sedimentation rate of 0.39 cm yr(-1), determined using (137)Cs, the presence of anthropogenic hydrocarbons in these sediment core deposited ca. 50 to 60 years ago. The historical background hydrocarbon concentrations increased significantly at the sediment surface and can be attributed to recent inputs. Although the oil present in the bay's sediments has undergone moderate weathering, biomarker analyses performed on core A samples likely indicated the presence of hydrocarbons from the DWH oil spill. The effects of oiling events on Barataria Bay and other marsh ecosystems in this region remain uncertain, as oil undergoes weathering changes over time.
authors.affiliation: Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA. Electronic address: dincerzeynepster@gmail.com.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Dincer Kırman
authors.affiliation: Geochemical and Environmental Research Group, Texas A&M University, College Station, TX 77845, USA.
authors.forename: José L
authors.initials: JL
authors.lastname: Sericano
authors.affiliation: Geochemical and Environmental Research Group, Texas A&M University, College Station, TX 77845, USA.
authors.forename: Terry L
authors.initials: TL
authors.lastname: Wade
authors.affiliation: Department of Oceanography, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Bianchi
authors.affiliation: Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Franco
authors.initials: F
authors.lastname: Marcantonio
authors.affiliation: Louisiana Universities Marine Consortium, 8124 Highway 56, Chauvin, LA 70344, USA; Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA 70118, USA.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Kolker
mesh_terms: D061006:Bays / Q000032:analysis; D002244:Carbon / Q000032:analysis; D017753:Ecosystem; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis* / Q000737:chemistry; D060851:Gulf of America; D008145:Louisiana; D010578:Petroleum / Q000032:analysis*; D059392:Petroleum Pollution / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014887:Weather; D053833:Wetlands
chemical_list: D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D002244:Carbon
keywords: Barataria bay; Chemical biomarker; Deepwater Horizon oil spill; PAHs; Salt marsh sediment; Stable isotopes