Assessing the footprint and volume of oil deposited in deep-sea sediments following the Deepwater Horizon oil spill

Stout, Scott A.; Rouhani, Shahrokh; Liu, Bo; Oehrig, Jacob; Ricker, Robert; Baker, G. O.; Lewis, Christopher G.

doi:10.1016/j.marpolbul.2016.09.046

Cited by 54 publications

(27 citation statements)

References 17 publications

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“…This marine oil snow sedimentation and flocculent accumulation (MOSSFA) event was an unexpected fate for a large amount of the spilled oil: the estimates that 5-10% or even 15% of the released oil was transported to the sea floor via MOSSFA (Valentine et al, 2014;Chanton et al, 2015;Stout et al, 2017) are almost certainly too low (Passow and Ziervogel, 2016).…”

Section: Research Articlementioning

confidence: 99%

The ecosystem baseline for particle flux in the Northern Gulf of Mexico

Giering¹,

Yan

Sweet

et al. 2018

Elementa: Science of the Anthropocene

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Response management and damage assessment during and after environmental disasters such as the Deepwater Horizon (DWH) oil spill require an ecological baseline and a solid understanding of the main drivers of the ecosystem. During the DWH event, a large fraction of the spilled oil was transported to depth via sinking marine snow, a routing of spilled oil unexpected to emergency response planners. Because baseline knowledge of particle export in the Northern Gulf of Mexico and how it varies spatially and temporally was limited, we conducted a detailed assessment of the potential drivers of deep (~1400 m depth) particle fluxes during 2012-2016 using sediment traps at three contrasting sites in the Northern Gulf of Mexico: near the DWH site, at an active natural oil seep site, and at a site considered typical for background conditions. The DWH site, located ~70 km from the Mississippi River Delta, showed flux patterns that were strongly linked to the Mississippi nitrogen discharge and an annual subsequent surface bloom. Fluxes carried clear signals of combustion products, which likely originated from pyrogenic sources that were transported offshore via the Mississippi plume. The seep and reference sites were more strongly influenced by the open Gulf of Mexico, did not show a clear seasonal flux pattern, and their overall sedimentation rates were lower than those at the DWH site. At the seep site, based on polycyclic aromatic hydrocarbon data, we observed indications of three different pathways for "natural" oiled-snow sedimentation: scavenging by sinking particles at depth, weathering at the surface before incorporation into sinking particles, and entry into the food web and subsequent sinking in form of detritus. Overall, sedimentation rates at the three sites were markedly different in quality and quantity owing to varying degrees of riverine and oceanic influences, including natural seepage and contamination by combustion products.

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Section: Research Articlementioning

confidence: 99%

The ecosystem baseline for particle flux in the Northern Gulf of Mexico

Giering¹,

Yan

Sweet

et al. 2018

Elementa: Science of the Anthropocene

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“…The spill interacted with the seafloor through deposition of oil snow from the plume and oil-contaminated surface water, affecting numerous deep-sea communities (Girard et al, 2018). An acute footprint of oil spillderived contamination was in an area ∼16 km southwest of the Macondo wellhead (Stout et al, 2017). This area contains two steel-hulled historic shipwrecks, the German submarine U-166, and the passenger and freight steamer Robert E. Lee (Damour et al, 2016;Hamdan et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Deep-Sea Biofilms, Historic Shipwreck Preservation and the Deepwater Horizon Spill

et al. 2019

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Exposure to oil from the Deepwater Horizon spill may have lasting impacts on preservation of historic shipwrecks in the Gulf of Mexico. Submerged steel structures, including shipwrecks, serve as artificial reefs and become hotspots of biodiversity in the deep sea. Marine biofilms on submerged structures support settlement of microand macro-biota and may enhance and protect against corrosion. Disruptions in the local environment, including oil spills, may impact the role that biofilms play in reef preservation. To determine how the Deepwater Horizon spill potentially impacted shipwreck biofilms and the functional roles of the biofilm microbiome, experiments containing carbon steels disks (CSDs) were placed at five historic shipwreck sites located within, and external to the benthic footprint of the Deepwater Horizon spill. The CSDs were incubated for 16 weeks to enable colonization by biofilm-forming microorganisms and to provide time for in situ corrosion to occur. Biofilms from the CSDs, as well as sediment and water microbiomes, were collected and analyzed by 16S rRNA amplicon gene sequencing to describe community composition and determine the source of taxa colonizing biofilms. Biofilm metagenomes were sequenced to compare differential gene abundances at spill-impacted and reference sites. Biofilms were dominated by Zeta-, Alpha-, Epsilon-, and Gamma-proteobacteria. Sequences affiliated with the Mariprofundus and Sulfurimonas genera were prolific, and Roseobacter, and Colwellia genera were also abundant. Analysis of 16S rRNA sequences from sediment, water, and biofilms revealed sediment to be the main known source of taxa to biofilms at impacted sites. Differential gene abundance analysis revealed the two-component response regulator CreC, a gene involved in environmental stress response, to be elevated at reference sites compared to impacted sites within the spill plume fallout area on the seafloor. Genes for chemotaxis, motility, and alcohol dehydrogenases were differentially abundant at reference vs. impacted sites. Metal loss on CSDs was elevated at sites within the spill fallout plume. Time series images reveal that metal loss at a heavily impacted site, the German Submarine U-166, has accelerated since the spill in 2010. This study provides evidence that spill residues on the seafloor may impact biofilm communities and the preservation of historic steel shipwrecks.

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“…The formation and sinking of MOS provide a pathway for the removal of oil from the water column that is not often considered when determining strategies for responding to oil spills (Daly et al, ; MOSSFA Report, ). Estimates of the amount of oil that sank to the seafloor during the Deepwater Horizon oil spill vary from 3% to 31% (Chanton et al, ; Stout et al, ; Valentine et al, ; Yan et al, ). Given this variability, and the potentially significant amount of oil sinking to the seafloor, it is important to understand the processes affecting MOS formation and the occurrence of MOSSFA events, as well as to have predictive models of the fate of oil spills that incorporate these processes for developing appropriate response strategies and determining mass budgets for spilled oil.…”

Section: Discussionmentioning

confidence: 99%

“…Studies of sediment samples around the DWH well site (Valentine et al, ) indicated that 4–31% of the oil sequestrated in the deep ocean reached the seafloor. Recent studies by Stout and German () and Stout et al () on the DWH sediments estimated that a total sedimented oil volume of 6.8–7.2% was not recovered during the DWH spill, while Romero et al () estimated that 21 ± 10% nonrecovered oil settled on the seafloor. Geochemical analysis of sediment cores in the DeSoto Canyon northeast of the DWH site suggests that some of the oil reached the seafloor in the form of large, heterogeneous aggregates.…”

Section: Introductionmentioning

confidence: 99%

“…Sedimentation of aggregates comprising oil and marine particles was observed during the DWH spill (Brooks et al, ; Passow, ; Passow & Ziervogel, ; Schwing et al, ), and some evidence exists for the formation of such aggregates during the IXTOC‐1 oil spill in the southern GoM in 1979–1980 and during other oil spills (Daly et al, ; MOSSFA Report, ; Vonk et al, ). Observations following the DWH event of a flocculant layer covering deep corals (White et al, ), the effects on the benthos (Montagna et al, ), and distribution of geochemical tracers and settled sediments at the bottom (Stout et al, ; Valentine et al, ), suggest that at least some of this oil arrived at the seafloor within rapidly sinking aggregates of oil, biogenic, and mineral particles (Marine Oil Snow, MOS). However, such a transport mechanism is generally not included in models of oil transport and fate.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Modeling of the Interactions of Oil, Marine Snow, and Riverine Sediments in the Ocean

et al. 2018

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Natural or spilled oil in the ocean can interact with marine snow and sediment from riverine sources and form Marine Oil Snow (MOS) aggregates including aggregates consisting of phytoplankton, detritus, and feces. Such aggregates have a fractal structure and can transport oil from the surface layers to greater depths in the ocean, eventually settling on the seafloor. In recent studies of the Deepwater Horizon and IXTOC‐1 oil spills in the Gulf of Mexico, this process was identified as one of the main mechanisms for transporting oil vertically in the water column. We have adapted a stochastic, one‐dimensional numerical model that uses coagulation theory to simulate MOS formation and sinking in the ocean and predict the time evolution of physical properties and spatial distribution of MOS. Here we present the model development, calibration, and validation with measured MOS field data in the Gulf of Mexico during the Deepwater Horizon spill. We use a sensitivity analysis to identify critical parameters, and suggest future model improvements and areas where further experimental investigation is needed to improve our understanding of MOS formation and sedimentation. The model can be used during response and planning activities associated with oil spills in the marine environments.

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Assessing the footprint and volume of oil deposited in deep-sea sediments following the Deepwater Horizon oil spill

Cited by 54 publications

References 17 publications

The ecosystem baseline for particle flux in the Northern Gulf of Mexico

The ecosystem baseline for particle flux in the Northern Gulf of Mexico

Deep-Sea Biofilms, Historic Shipwreck Preservation and the Deepwater Horizon Spill

Numerical Modeling of the Interactions of Oil, Marine Snow, and Riverine Sediments in the Ocean

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