Oil spill chemical dispersant found to severely harm moon jellyfish
A study by the Florida International University’s Southeast Environmental Research Center proves that the chemical used as a dispersant following the 2010 Deepwater Horizon oil spill can severely harm and even kill jellyfish.
They found that crude oil or weathered oil alone does not cause significant adverse effects in moon jellyfish, a species that is commonly found in the Gulf of Mexico where the oil 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. The Corexit 9500 was used to disperse oil slicks in the water column during the 2010 oil spill.
“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.
In April 2010, the Deepwater Horizon oil spill released millions of gallons of crude oil into the Gulf of Mexico. Corexit 9500 was then applied by injection at the source of the oil and to the sea surface. According to Rand, the application of the chemical dispersant is critical in preventing significant oiling of sensitive shoreline habitats during an oil spill mitigation response.
“The role of jellyfish as consumers and as prey increases the need to understand how exposure to crude oil, weathered oil and dispersants affect this group of organisms,” Rand said. “Selecting a variety of animal and plant species native to an ecosystem of interest provides a greater overall understanding of potential risks to the ecosystem.”
Standard test organisms like mysid shrimp and fish, such as inland silversides and sheepshead minnows, have been traditionally used in past toxicity studies conducted in laboratories to examine the biological effects of crude oil, weathered oil and chemical dispersants in marine ecosystems. The Gulf of Mexico is home to one of the most diverse populations of anemones, corals, and jellyfish in the world with more than 115 species taking up residence in its warm waters. According to the researchers, jellyfish are often overlooked in marine toxicity assessments since their ecological importance is often underestimated.
Source: FIU News