Small-Scale Resuspension and Redistribution of Surface Sediments in the Northeast Gulf of Mexico
Following the release of ~4.9 million barrels of oil into the Gulf of Mexico from the Macondo wellhead, a vast area of the seafloor contained recently deposited marine sediments contaminated by the oil spill. The initial deposition of these contaminated marine sediments was likely not the end of the journey for the particles. Downslope gravitational processes and events of increased current speed in the deep ocean setting can result in recently deposited sediments to resuspend and be moved laterally with the current flow, increasing the area effected by the oil spill. Erosion experiments performed in a closed-loop resuspension flume were completed on 23 sediment cores collected from near the Macondo wellhead and areas to the SE. Using flow modeling of the Gulf of Mexico, core sites were chosen to be in areas where erosion or deposition is thought to be the dominant process of that coring location. Sites were reclassified based upon ease of initial transport of material and the shear stress of pulses, or peaks, in eroded sediment volume. All cores had erosion begin at -2(4.6 cm s-1) and nearly all cores had large pulses of sediment eroded >0.48 dyne cm-2 (13.7 cm s-1). Surface sediment characteristics revealed older, rebound material was more easily resuspened than newly deposited material. This suggests that the area effected by the DwH oil spill has increased over time as contaminated material has been transported by natural process to deep waters SE of the wellhead.
Resuspension, Flume, Gulf of Mexico, Geology, Geomorphology, Oceanography, Sedimentology
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