Jellyfish become unintended victims of oil spill mitigation

chemical used to disperse oil following the 2010 Deepwater Horizon oil spill has been proven to severely harm and even kill jellyfish.

A study by Florida International University's Southeast Environmental Research Center found crude oil and weathered oil alone did not cause significant adverse effects in moon jellyfish, a species commonly found in the Gulf of Mexico where the spill occurred. But the crude oil, in the presence of the chemical dispersant Corexit 9500, caused changes in color of the jellyfish, irregularities in their bell shape, tissue degradation and even death. Jellyfish exposed to the dispersant alone also experienced acute toxicity. Corexit 9500 was used in the 2010 spill to disperse oil slicks in the water column.
"The use of dispersant in response to an oil spill is generally regarded as the best option to reduce biological impact and protect shoreline habitats, but it comes with trade-offs," said Gary Rand, co-author of the study and professor in the Department of Earth and Environment at FIU.
The Deepwater Horizon oil spill released millions of gallons of crude oil into the Gulf of Mexico in April 2010. Corexit 9500 was applied by both injection at the source of the oil leak and to the sea surface. According to Rand, its application is critical in preventing significant oiling of sensitive shoreline habitats during a


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