Cheldina Jean, American University
The problem: The Deepwater Horizon oil spill that occurred in April 2010 is known as the nation’s most detrimental offshore environmental disaster. Over the course of almost three months, approximately 134 million gallons of crude oil was released into the Gulf of Mexico. Tens of thousands of marine organisms, including dolphins, sea turtles, 93 bird species, and marine plants such as mangroves, whose roots hold together the eroding coasts of Louisiana and South Florida, were negatively affected by this calamity.
Estuarine organisms, particularly sensitive early life stages, are particularly vulnerable to oil pollution given the stressful environmental conditions of their habitat. Estuaries experience daily tidal fluctuations in light penetration, temperature, and salinity; and the range of these factors is expected to increase with global climate change. My project this summer consists of testing the effects of oil on the early life stages of estuarine organisms under various environmental conditions. This research will help us understand how their populations may be affected.
Grass shrimp are commonly found in estuarine waters of South Carolina and along the Gulf and Atlantic coastlines. Grass shrimp are detritivores, playing an important role in the salt marsh by recycling the nutrients of decaying matter back into the food chain. They are also an important prey species for commercially and recreationally important marine organisms, such as spotted sea trout and red drum (Coen & Wenner, 2005). This research project focuses on the role abiotic stressors such as ultraviolet light, temperature, and salinity play on the survival of grass shrimp (Palaemonetes pugio female grass shrimp embryos and larvae exposed to oil.
Crude oil is a complex mixture of chemicals, including a group of compounds called polycyclic aromatic hydrocarbons (PAHs). Some PAHs are chemically altered in the presence of ultraviolet (UV) light, causing an increase in the toxicity of oil (Alloy et al., 2017). In addition, thermal stress from rising global temperatures may affect the ability of marine organisms to metabolize and detoxify contaminants they take up (DeLorenzo et al., 2009). Salinity is another environmental factor to consider because it can alter the solubility of chemical contaminants and thus change the level of chemical exposure.
Every oil spill has different conditions surrounding it, so it is important to understand how factors such as UV light, temperature, and salinity affect oil toxicity in the early life stages of estuarine organisms. Although we cannot eliminate oil pollution in the ocean, the results of this research will help us understand how multi-stressors and oil affect the early life stages of aquatic organisms and will help governments and citizens take action in oil spill response and remediation.
I would like to thank my mentor Marie DeLorenzo and co-mentor Katy Chung for guiding me through this research. This project is supported by the Fort Johnson REU Program, NSF DBI-1757899.
- Alloy, M., Garner, T. R., Bridges, K., Mansfield, C., Carney, M., Forth, H., … & Bonnot, S. (2017). Co‐exposure to sunlight enhances the toxicity of naturally weathered Deepwater Horizon oil to early lifestage red drum (Sciaenops ocellatus) and speckled seatrout (Cynoscion nebulosus). Environmental toxicology and chemistry, 36(3), 780-785.
- Coen, L., & Wenner, E. (2005). Grass shrimp. South Carolina State Documents Depository.
- DeLorenzo ME, Wallace SC, Danese LE, Baird TD (2009) Temperature and salinity effects on the toxicity of common pesticides to the grass shrimp, Palaemonetes pugio. J Environ Sci Health B 44:455–460.