TALLAHASSEE, Fla., Feb. 14 (UPI) -- U.S. researchers say hydrocarbon gases released during the Deepwater Horizon Gulf of Mexico oil spill could have an "extensive" effect on ocean chemistry.
A study by scientists from the University of Georgia and Florida State University found that up to 500,000 tons of gaseous hydrocarbons were emitted into the deep ocean, an FSU release said Monday.
Such a large discharge, causing chemical concentrations 75,000 times the norm, could create zones of "extensive and persistent depletion of oxygen" as microbial processes degrade the gaseous hydrocarbons, the study said.
In the 2010 blowout nearly a mile below the ocean surface, deep sea processes of high pressure and low temperatures trapped the escaping gases in a deep layer of the gulf, the researchers said.
The methane and other gases will remain in the deep layers and be consumed by microbes in a process known as oxidation, which can lead to low-oxygen waters, Samantha Joye, UGA professor of marine sciences, said.
"We're not talking about extensive hypoxic areas offshore in the Gulf of Mexico," Joye said. "But the microbial oxidation of the methane and other alkanes will remove oxygen from the system for quite a while because the time scale for the replenishment of oxygen at that depth is many decades."