About 88,200 gallons of oil were released from an underwater pipeline operated by Shell about 90 miles off the coast of Louisiana, according to news reports.
Much of the oil has been recovered, and there are as yet no reported impacts on wildlife.
According to the researchers, the black carbon continued to sink for two months after the oil fires were extinguished, while other contaminants, including barium, accumulated for at least five months.
“The traps collected this material months after everyone thought the leak was over,” Passow said.
Some researchers have contended that contaminants found on the seafloor could be coming from natural oil seeps.
But Yan and colleagues used various “fingerprinting” techniques to demonstrate that the hydrocarbons in the water were derived from crude oil of the kind leaking from the Deepwater Horizon site.Dark clouds of smoke and fire emerge as oil burns during a controlled fire in the Gulf of Mexico, . Navy The paper “provides a likely mechanism for the impact to deep sea corals discovered outside of the depth range and most likely flow path of the Deepwater plume of oil and gas that formed during the spill,” said Chuck Fisher, a marine biologist at Penn State who was not directly involved in the study.A new study found black carbon left from the burns joined a “dirty blizzard” of contaminants that eventually settled on the seafloor. Fisher’s work documented damage to corals following the spill. Some of the oil was recovered, evaporated or was deliberately burned at the surface.Although the oil was undetectable in surface waters within a few weeks, the deeper environmental consequences were unclear because the mechanisms that transport petroleum hydrocarbons to the ocean floor were not well understood.Yan and his colleagues used sediment traps to collect diatoms and other matter slowly sinking through the water and found contaminants clinging to the tiny particles, including black carbon left over from burning oil slicks, and barium and olefin, which are used in drilling mud.The researchers found that the movement of contaminants from the water column to the seafloor was intensified during August and September 2010 by an exceptionally large bloom of diatoms.These phytoplankton produce a mucous, particularly when dying, that acts as a glue for other particles in the water.Between April 20 and July 15, 2010, about 200 million gallons of crude oil gushed into the Gulf of Mexico from a blown well beneath the Deepwater Horizon oil rig—the largest marine oil spill in U. Some washed ashore; still more was broken down by chemical dispersants and consumed by bacteria.But a large portion, perhaps a quarter, has been unaccounted for.The work, published May 30 in the , confirms that contaminants found in the water column and on the seafloor were indeed from the Deepwater Horizon spill, and not from the many natural oil seeps in the Gulf.The initial dispersal of materials in the water made pollutants hard to detect, but the eventual accumulation of “marine snow” concentrated the toxins on the seabed, where they can enter the food web, possibly affecting fish and corals in deep waters.