Mapping spatial and temporal variation of seafloor organic matter Δ14C and δ13C in the Northern Gulf of Mexico following the Deepwater Horizon Oil Spill
2021
Rogers, Kelsey L. | Bosman, Samantha H. | Wildermann, Natalie | Rosenheim, Brad E. | Montoya, Joseph P. | Hollander, David | Zhao, Tingting | Chanton, Jeffrey P.
Following the Deepwater Horizon oil spill of 2010, large amounts of biodegraded oil (petrocarbon) sank to the seafloor. Our objectives were to 1) determine post-spill isotopic values as the sediments approached a new baseline and 2) track the recovery of affected sediments. Sediment organic carbon δ¹³C and Δ¹⁴C reached a post-spill baseline averaging −21.2 ± 0.9‰ (n = 129) and −220 ± 66‰ (n = 95). Spatial variations in seafloor organic carbon baseline isotopic values, ¹³C and ¹⁴C, were influenced by river discharge and hydrocarbon seepage, respectively. Inverse Distance Weighting of surface sediment Δ¹⁴C values away from seep sites showed a 50% decrease in the total mass of petrocarbon, from 2010 to 2014. We estimated a rate of loss of −2 × 10⁹ g of petrocarbon-C/year, 2–11% of the degradation rates in surface slicks. Despite the observed recovery in sediments, lingering residual material in the surface sediments was evident seven years following the blowout.
显示更多 [+] 显示较少 [-]