The complexity of what happened in the Deepwater Horizon/BP drilling platform explosion and resulting sea-floor oil gusher that flowed for 87 days is only dwarfed by what has happened in the time since. The clean-up, which began immediately, has been a Herculean effort that continues to this day. But a new perspective article in Nature by Samantha Joye and her colleagues brings attention to one problematic aspect of the clean-up: the use of chemical dispersants to break up the oil into small droplets that could be easily degraded by microbes. There seems to have been no definitive evidence that dispersants are actually effective in this way:
The article, published May 6, summarizes previous research from laboratory and field studies assessing the impacts of dispersants, which have generated inconsistent results.
"This comprehensive review illustrates a compelling need not only for more studies aimed at assessing the impacts of dispersants on microbial communities and microbial processes in marine ecosystems, but also underscores the necessity for using standardized methods and consistent metrics to document dispersant effects on microbial populations," said Joye, the UGA Athletic Association Professor of Arts and Sciences and a professor of marine sciences in the Franklin College of Arts and Sciences.
The researchers document historical context for the use of dispersants, their approval by the Environmental Protection Agency and the uncertainty about whether they stimulate or in fact inhibit the microbial degradation of oil in marine ecosystems.
Initial use of the dispersants on this scale were experimental in the first place. You see the word 'unprecedented' used frequently to describe the Deepwater Horizon/BP spill, one of the worst environmental catastrophes in history, and this extends to some of the strategies used to protect the shorelines and stem the visible pollution therefrom. Joye's work helps keep attention focused on what we cannot see and the longer-term implications of what was done - and the use of dispersants going forward. Should they be used? Our marine scientists say the jury is most definitely still out.
Image: C-130 Hercules from the Air Force Reserve Command's 910th Airlift Wing drops an oil-dispersing chemical into the Gulf of Mexico May 5, 2010, as part of the Deepwater Horizon Response effort. via wikimedia commons.