Center for the Environment

Leading researcher to deliver Purdue lecture on Gulf oil, gas spill

March 8, 2011

WEST LAFAYETTE, Ind. - A prominent researcher who has studied the environmental impact of last year's massive oil spill will speak at Purdue next week as part of the university's effort to develop a research community in this field.

Ian R. MacDonald, a professor of biological oceanography at Florida State University, will deliver the lecture, "Natural and Unnatural Oil in the Gulf of Mexico: Lessons of Comparison for the BP Discharge," at 3:30 p.m. March 3 in Stewart Center, Room 202.

The talk is free and open to the public. Event sponsors are Purdue's Global Sustainability Initiative, Purdue Oil Spill Community, Center for the Environment, Energy Center, Purdue Water Community, College of Engineering and the School of Mechanical Engineering.

"Some experts say an abundance of hydrocarbons in the Gulf of Mexico over the years may have preconditioned its ecosystem to rebound more quickly from the massive BP spill last summer," said event co-organizer John Bickham, director of Discovery Park's Center for the Environment. "Professor MacDonald will discuss whether that assumption stands up against the massive amount of toxic gases that were discharged and health implications for humans and marine life."

The explosion at the BP Deepwater Horizon rig killed 11 workers on April 20 and led to millions of gallons of oil and gas spewing into the Gulf of Mexico over an 84-day period. 

MacDonald was part of a research team that released a study on Feb. 13, showing that up to 500,000 tons of gaseous hydrocarbons -- with an energy equivalent of more than 3 million barrels of oil -- were emitted into the deep ocean from the oil discharge.

The researchers concluded that such a large gas discharge, which generated concentrations 75,000 times the norm, could result in small-scale zones of "extensive and persistent depletion of oxygen" as microbial processes degrade the gaseous hydrocarbons.

"This  very large and very sustained release of gas overwhelmed the ability of the bacteria to consume it quickly," MacDonald said. "If we're going to be prepared for the next catastrophe or the next near miss, we need to do so based on the best data available. And that's what we hope to do with this study."

The study appeared in the early online edition of the journal Nature Geoscience. Joining MacDonald on the research team were Samantha Joye of the University of Georgia, Ira Leifer of the University of California-Santa Barbara, and Vernon Asper of the University of Southern Mississippi.

The researchers examined samples from 70 sites around the leaking wellhead during a research cruise aboard the R/V Walton Smith in late May and early June. They combined their data with estimates of the volume of oil released to arrive at a figure that allows scientists to quantify, for the first time, the gas discharge in terms of equivalent barrels of oil. 

MacDonald said the team calculated a gas discharge that's the equivalent of either 1.6 to 1.9 or 2.2 to 3.1 million barrels of oil, depending on the method used. Although the estimate reflects the uncertainty still surrounding the spill, even the lowest magnitude represents a significant increase in the total hydrocarbon discharge, he said. Gases released were mostly methane and pentane.

"These calculations increase the accepted government estimates by about one-third," said MacDonald, who also is a member of the National Wildlife Federation's science advisory panel.

MacDonald received his doctorate in oceanography from Texas A&M University in 1990 for dissertation work on the spatial ecology of natural hydrocarbon seeps. His research has retained a strong Gulf of Mexico focus but includes work on the deep-sea biology of hydrothermal vents and the Arctic Ocean. He specializes in application of imaging technology and satellite remote sensing.

More than 4 million barrels of oil spewed into the Gulf off the coast of Louisiana following the deadly explosion at the Macondo well. The BP oil spill, which leaked an estimated 50,000-60,000 barrels per day, is roughly 20 times more than the Exxon Valdez accident in 1989. Oil discharge from the BP well was shut off on July 15 and permanently sealed on Sept. 19.

Since the BP spill, Purdue has focused on building its oil research capacity for working with industry and government agencies in addressing and future prevention of these disasters. The Purdue Oil Spill Community has organized workshops and hosted lectures by researchers and includes an interdisciplinary team of Purdue geologists, petroleum engineers, chemical and environmental engineers, economists and social scientists.

Writer:  Phillip Fiorini, 765-496-3133, pfiorini@purdue.edu

Sources:  John Bickham, 765-494-4366, rcosier@purdue.edu

                   Ian MacDonald, 850-644-5498, imacdonald@fsu.edu

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