skip to main content


Title: Sedimentation pulse in the NE Gulf of Mexico following the 2010 DWH blowout

The objective of this study was to investigate the impacts of the Deepwater Horizon (DWH) oil discharge at the seafloor as recorded in bottom sediments of the DeSoto Canyon region in the northeastern Gulf of Mexico. Through a close coupling of sedimentological, geochemical, and biological approaches, multiple independent lines of evidence from 11 sites sampled in November/December 2010 revealed that the upper ~1 cm depth interval is distinct from underlying sediments and results indicate that particles originated at the sea surface. Consistent dissimilarities in grain size over the surficial ~1 cm of sediments correspond to excess 234Th depths, which indicates a lack of vertical mixing (bioturbation), suggesting the entire layer was deposited within a 4–5 month period. In addition, a time series from four deep-sea sites sampled up to three additional times over the following two years revealed that excess 234Th depths, accumulation rates, and 234Th inventories decreased rapidly, within a few to several months after initial coring. The interpretation of a rapid sedimentation pulse is corroborated by stratification in solid phase Mn, which is linked to diagenesis and redox change, and the dramatic decrease in benthic formanifera density that was recorded in surficial sediments. Results are consistent with amore » brief depositional pulse that was also reported in previous studies of sediments, and marine snow formation in surface waters closer to the wellhead during the summer and fall of 2010. Although sediment input from the Mississippi River and advective transport may influence sedimentation on the seafloor in the DeSoto Canyon region, we conclude based on multidisciplinary evidence that the sedimentation pulse in late 2010 is the product of marine snow formation and is likely linked to the DWH discharge.« less
 [1] ;  [2] ;  [3] ;  [3] ;  [1] ;  [4] ;  [5] ;  [6] ;  [1] ;  [7] ;  [7] ;  [7] ;  [8] ;  [3] ;  [9]
  1. Eckerd College, St. Petersburg, FL (United States)
  2. Eckerd College, St. Petersburg, FL (United States); Univ. of South Florida, St. Petersburg, FL (United States)
  3. Univ. of South Florida, St. Petersburg, FL (United States)
  4. Utrecht Univ., Utrecht (The Netherlands); Royal Netherland Institute for Sea Research, Texel (The Netherlands)
  5. Utrecht Univ., Utrecht (The Netherlands)
  6. Florida State Univ., Tallahassee, FL (United States)
  7. Georgia Inst. of Technology, Atlanta, GA (United States)
  8. Environchron, Bradenton, FL (United States)
  9. Univ. of California, Merced, CA (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Additional Journal Information:
Journal Volume: 10; Journal Issue: 7; Journal ID: ISSN 1932-6203
Public Library of Science
Research Org:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Org:
Country of Publication:
United States
58 GEOSCIENCES sediment; biomarkers; carbonates; sedimentation; manganese; scanning electron microscopy; surface water; texture