Deepwater Horizon's Footprint Actually A 'Bathtub Ring'

The lasting legacy of the 2010 Deepwater Horizon oil spill in the Gulf of Mexico can still be seen on the ocean floor.

Deepwater Horizon's Footprint Actually A 'Bathtub Ring'
U.S. Coast Guard

Two hundred ten million gallons is a lot of oil. So much so that four years after the Deepwater Horizon spill, it can still be seen on the ocean floor of the Gulf of Mexico. 

That's according to a new study, which says the 2010 spill — the biggest oil spill in history — left what it calls a "bathtub ring" on the gulf. (Video via NBC)

The study says hydrocarbons from the oil plume of the well have contaminated an area of some 1,200 square miles in the deep waters of the gulf. 

The study's lead author David Valentine spoke on how the geography of the ocean floor in the gulf, keeps the residual oil in the gulf. (Video via PBS)

DAVID VALENTINE VIA AMERICAN SOCIETY FOR MICROBIOLOGY: "At this depth of 3,000 or 4,000 feet, it's bounded on three sides so there's no current that flushes through. ... Water tends to slosh back and forth."  

So if the water sloshes around the gulf, like in a bathtub, and takes the oil with it, it makes sense that there'd be a bathtub ring around the gulf. And it's easy to see in samples from the ocean floor. 

CHIP REID FOR CBS"This is mud."

MANDY JOY: "Yeah, and this is the oily layer."

REID: "That's from the spill four years ago. Oily residue that she worries could adversely affect marine life in the longer term."  

BP has unsurprisingly disputed the study's findings, saying the researchers haven't been able to distinguish between oil from the spill and naturally occurring oil in the gulf. 

But Valentine told The Times-Picayune the oil from the well was easy to trace because, "The discharge from the Macondo well simply swamped the signal from other sources in a clear and distinctive way that points right to the Macondo well as source."

BP has plenty of incentive to try to downplay the study's findings. It's still wrestling with the legal fallout of the spill as the affected gulf states try to get compensation for the damage. 

This video includes an image from Getty Images.