Deanna Hausman, University of Texas at Austin
Pretty much everyone knows that oil is toxic, unfortunately. We’ve all seen images of birds or otters covered in oil, or seen wetlands destroyed due to an oil spill. But what many people may not know is certain factors, even rays from the sun, can increase the toxicity of oil. UV light—what gives us sunburns—can increase the toxicity of oil by over 1000 times in some cases, which allows it to kill more organisms and damage more of the ecosystem.
This is a big problem. And like in everything else, you can’t start solving a problem until you completely understand it. Before experts can start to clean up an oil spill, they have to make predictions, and determine how toxic the oil is going to be, what organisms are going to be more sensitive to it, and what conditions exist that could make the oil more toxic.
Which is where my research comes in! This summer, I’m studying the effects of oil on larval grass shrimp. They’re kind of cute little creatures: as larvae, they swim upside-down, and have giant eyes. Most importantly, as adults, they’re very important to the ecosystem. They’re an important food source for many larger fish and crabs, and they’re also detrivores, meaning they break down waste on the seafloor into smaller pieces, that tiny organisms such as plankton can eat. Therefore, they’re important for organisms both at the top and bottom of the food chain, and if their populations are harmed, it can have a huge negative impact on a large number of other organisms.
Adult grass shrimp
Specifically, my work this summer is focusing on the toxic effects of thin oil sheens and oil mixed in with sediment, as well as the developmental effects of oil. Previously, some studies have worked to determine that very thin oil sheens can be toxic, but they largely focused on deep-water organisms, not estuarine species. My study will work to determine how thin oil sheens can affect estuarine species. In addition, the sediment tests will determine how estuarine species might be affected by oil sinking down after a spill- a situation they are often exposed to. Both these studies will also evaluate what impact UV light has on oil in these situations. Finally, studying the impact of oil on shrimp development will help determine what the long-term affects an oil spill may have.
The set-up of the oil sheen experiment. One tank contains pure seawater, to serve as a control, while the other contains the oil sheen. Some shrimp are caged and some are swimming free, in order to determine whether shrimp need to swim through the oil to be affected or not
All of this research will help people to make predictions about the damage that will occur in the event that an oil spill does occur in or near an estuary.
I’d like to thank my mentors, Dr. Marie Delorenzo and Dr. Paul Pennington, for their guidance and NOAA for providing me with lab space and equipment.
Finch, B.; Stubblefield, W. Photo-enhanced toxicity of fluoroanthene to Gulf of Mexico marine organisms at different larval ages and ultraviolet light intensities. Environmental Toxicology and Chemistry. 2015, 35, 1113-1122.