Oil remains after Gulf cleanup

Over 10 million gallons remain on the Gulf floor from the Deepwater Horizon oil spill. SPECIAL TO THE ORACLE

During the 2010 Deepwater Horizon oil spill, more than 200 million gallons spread across the Gulf of Mexico. Though BP claimed the cleanup was done last year, new research indicates up to 10 million gallons remain on the ocean floor. 

Though the oil may not be observed above the surface, researchers say ecosystems may be suffering below.

USF researchers began a collaborative effort in 2010 with Florida State University (FSU) professors to further study the effects of this material and how it affects the benthic, or bottom-dwelling, ecosystem. 

FSU professor of oceanography, Jeff Chanton, led the research effort. His team discovered that over 3,000 square miles of the Gulf showed evidence of oil on its floor. 

The team observed the top of the mud in some areas had less carbon-14, a compound which oil lacks, than that of the layer underneath. They searched for areas without carbon-14, which would indicate the presence of oil. 

Though the oil’s existence is now known, Chanton said the chance of removal is slim to none. 

“There isn’t much that we can do about the oil,” Chanton said. “We don’t know the long-term effects of the oil’s presence as of yet, but that’s what we’re trying to find out.” 

With Chanton’s findings released earlier this month, USF will take part in future findings with a $20 million grant approved for the next five years. 

David Hollander and Steve Murawski are leading the cause and working within the Center for Integrated Modeling and Analysis of the Gulf Ecosystem (C-IMAGE), sponsored by USF. 

Hollander, a USF associate professor of chemical oceanography, conducted his own research in 2012 on deep marine blowouts. 

Hollander discovered that oil does not always float. He said oil on the surface eventually mixes with minerals coming from rivers and algae from the ocean, weighing it down until it sinks.

The collaboration aims to study the effects on the ecosystem and food web not only in the short-term but long-term as well. They will review the effects of the Horizon spill, as well as the 1979 Gulf oil spill, known as Ixtoc, to measure the damage done over the past 35 years. 

“There’s a great idiom in geology that says ‘the present is the key to the past, but the past provides a window to see into the future,’” Hollander said. “The work in the Ixtoc system will let us see the similarities between that spill and the Horizon spill as well as the last effects in the contaminated area.” 

Early research in the Bay of Campeche has shown high amounts of oil on the sea floor still remain in this region due to Ixtoc spill.

Murawski and Hollander plan to do field work in Mexico at the Ixtoc site this summer to examine aquatic life and the lasting effects of oil on its habitats. 

Hollander said a fish’s ear bone records information like a tree ring, providing data on age and quality of life for as many as seven years into the past.  

“Working on fish today gives you a vision for what happened in the past,” Hollander said. “Examining fisheries from the Ixtoc spill will help us march our way forward in time to today’s window to get a coherent, continuous understanding of how the fish populations were affected and how they returned to today’s levels.” 

Hollander said some locations in the Gulf have recovered but others have continued to deteriorate. Even for those that have recovered, the sea life is not the same as that before the Horizon blowout. 

Looking to the future, Hollander said he hopes this research can establish a better response strategy for future spills and how to properly disperse the oil after it enters the ocean. 

“You get the impression that people are focusing almost exclusively in the Gulf of Mexico,” Hollander said. “But let it be known that there’s been oil drilling in the Pacific coast, soon the Atlantic seaboard and the Arctic reserves.”

Chanton, Hollander and Murawski said there is a need for better handling of oil spills by the world’s governments. Hollander said the complexity of the ocean comes across as too vast of a system to contain, with countless elements to consider beyond just the water and sea life.

“The ocean’s a very special beast,” Hollander said. “You can understand the science of the ocean best … if you come at it from a basic science discipline to make further advancements.”