Golf ball-size clumps of oil and sand left behinfrom the 2010 Deepwater Horizon oil spill, sometimes referred to as “tarballs,” may take more than 30 years to decompose, Florida State University researchers say. 

How we know this. 

The research team conducted a three-year experiment on Pensacola Beach where they placed tarballs from the 2010 spill into mesh containers tethered to PVC pipe and buried them along the beach. The team measured the tarballs periodically over the time period to calculate the rate of degradation.  

Why it matters.  

The tarballs left along the beaches contain substances that are harmful to the environment and to humans. Understanding the fate of buried oil is critical.  

The good news is that the area’s sandy beaches help speed up the biodegradation process. The team said that without the ecological properties of a sandy beach, the same tarballs could take more than a century to break down.  

“The beach, breathing in tidal rhythm, thus can be compared to a large organism that aerobically ‘digests’ the organic matter — including oil — by inhaling oxygen and exhaling carbon dioxide,” FSU professor of oceanography Markus Huettel told FSU news. 

But, there’s always a tipping point. If too much oil accumulates, once-pristine beach sands can become impenetrable to oxygen and inhospitable to microbes that help break down the oil. This can lead to hypoxic, or oxygen-deprived zones.  

Where can I learn more?  

Kudos to:  

FSU professor of oceanography Markus Huettel and graduate student Ioana Bociu were the study authors. This study was funded by the Gulf of Mexico Research Initiative, the National Science Foundation, the Florida Institute of Oceanography and the Northern Gulf Institute. 

Featured image by Geoff Livingston