Mapping spatial and temporal variation of seafloor organic matter Δ14C and δ13C in the Northern Gulf of Mexico following the Deepwater Horizon Oil Spill. (March 2021)

• Record Type: Journal Article
• Authors: Rogers, Kelsey L.; Bosman, Samantha H.; Wildermann, Natalie; Rosenheim, Brad E.; Montoya, Joseph P.; Hollander, David; Zhao, Tingting; Chanton, Jeffrey P.
• Is Part Of: Marine pollution bulletin. Volume 164(2021)
• Publication Date: 2021-03
• Subjects: Deepwater Horizon -- Radiocarbon -- Sediments -- Gulf of Mexico -- Carbon isotopes -- Petrocarbon; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2021.112076
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: 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 δ 13 C and Δ 14 C 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, 13 C and 14 C, were influenced by river discharge and hydrocarbon seepage, respectively. Inverse Distance Weighting of surface sediment Δ 14 C 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 × 10 9 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. Highlights: By 2014 50% of sedimented DWH petrocarbon was removed at 2–11% of surface oil degradation rates (81). GOM seafloor 13 C and 14 C variation was driven by river discharge and hydrocarbon seepage. Post-spill sediment organic matter baseline was δ 13 C = −21.2 ± 0.9‰ ( n = 129), Δ 14 C = −220 ± 66‰ ( n = 95).