![Fig. 2 Spatial DWH cumulative extents. (A) Cumulative NESDIS anomaly daily composites integrated from 20 April 2010 to 21 July 2010. Daily fishing closures are marked with gray lines; the cumulative fishing closure area is marked with a thick dashed yellow line. The black star represents the location of the DWH blowout [adapted by permission from Springer-Nature: Scenarios and Responses to Future Deep Oil Spills: Fighting the Next War by S. Murawski, C. Ainsworth, S. Gilbert, D. Hollander, C. Paris, M. Schlüter, D. Wetzel, Eds., 2019 (18)]. (B) Cumulative value of daily average oil concentrations (ppb), integrated across the same time span as (A) and across water depths. Vertical depth layers are 0 to 1 m, 1 to 20 m, and in 20-m increments down to 2500 m. Sediment and water samples with higher-than-background concentration are marked in bright green and dark blue circles, respectively [adapted by permission from Springer-Nature: Scenarios and Responses to Future Deep Oil Spills: Fighting the Next War by S. Murawski, C. Ainsworth, S. Gilbert, D. Hollander, C. Paris, M. Schlüter, D. Wetzel, Eds., 2019 (18)]. Red crosses in (B) represent approximate locations of DWH-related oil detections reported in previous studies: (i) (9), (ii) (7), (iii) (12), (iv) (13), and (v) (15). Daily fishery closures are marked with black polygons; the cumulative fishery closure area is marked with a dashed thick polygon. AB, Apalachee Bay; DP, Deep Plume; EFS, East Florida Shelf; FK, Florida Keys; LC, Loop Current System; TXS, Texas Shores; WFS, West Florida Shelf. (C) Categorization of the modeled oil spill are as follows: (i) nontoxic, PAH concentrations above background level and smaller than 0.5 and 1 ppb at the surface (depth, 0 to 1 m) and in the water column (depth, >1 m), respectively; (ii) toxic-to-biota and invisible, PAH concentrations 0.5 to 17 ppb at the surface and above 1 ppb in the water column; and (iii) toxic and visible, PAH concentrations above 17 ppb. In (C), categories were computed according to maximal concentrations across time. (D) Duration of toxic concentrations across the domain. (E) LC50 of 12 experiments examining the photoinduced toxicity to blue crab (31), fiddler crab (33), mahi mahi (29, 30), red drum (32), and speckled sea trout (32) (for more details, see table S2). (F) The spatial extent of the toxic concentrations from (E); color codes in (F) are according to bar colors in (E), representing concentrations exceeding LC50. In (F), toxic PAH of 0.5 ppb was concentrations were considered for surface waters only (depth, 0 to 1 m).](https://i0.wp.com/idsc.miami.edu/wp-content/uploads/2021/03/Spatial-cumulative-extents-of-the-Deepwater-Horizon-oil-spill-Berenshtein-et-al-2020-Science-Advances.jpg?resize=940%2C530&ssl=1)
Invisible Oil Beyond the Deepwater Horizon Satellite Footprint
Abstract Major oil spills are catastrophic events that immensely affect the environment and society, yet determining their spatial extent is a highly complex task. During the Deepwater Horizon (DWH) blowout, ~149,000 km2 of the Gulf of Mexico (GoM) was covered by oil slicks and vast areas of the Gulf were closed for fishing. Yet, the satellite footprint does not necessarily capture the entire oil spill extent. Here, we use in situ observations and oil spill transport modeling to examine the full extent of the DWH spill, focusing on toxic-to-biota (i.e., marine organisms) oil concentration ranges. We demonstrate that large areas of the GoM were exposed to invisible and toxic oil that extended beyond the boundaries of the satellite footprint and the fishery closures. With a global increase in petroleum production–related activities, a careful assessment of oil spills’ full extent is necessary to maximize environmental and public safety.
Invisible Oil Beyond the Deepwater Horizon Satellite Footprint by Igal Berenshtein, Claire B. Paris, Natalie Perlin, Matthew M. Alloy, Samantha B. Joye, Steve Murawski. Science Advances, 12 Feb 2020: EAAW 8863