Oil Spills, Climate Change, and Grass Shrimp

Cheldina Jean, American University

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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.

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Gravid (egg carrying) female grass shrimp (Source)

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.

Literature Cited:

  1. 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.
  2. Coen, L., & Wenner, E. (2005). Grass shrimp. South Carolina State Documents Depository.
  3. 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.

 

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Small Steps to Save the Sea Turtles

Kelly Townsend, Elmhurst College

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Turtle trawl on the R/V Lady Lisa. Photograph authorized by NMFS Section 10(A)(1)(a) permit 19621.

The problem: Do you like sea turtles? As for me, I have fallen in love with these cute creatures who occupy parts of the ocean. Seeing them pop their heads up or glide through the water always amazes me, but many species are endangered. A lot of effort has gone into saving them since sea turtles play an important role in the marine ecosystem. The marine ecosystem makes up a part of our world that is deeply loved but also threatened. Sea turtles help marine ecosystems function by limiting the amount of seagrass beds and sponges through consumption (McClenachan et al., 2006). Therefore, sea turtles presence in the environmental community is key to ecosystem restoration where their numbers have dropped and seagrass disease has been able to spread and coral overgrowth has increased. In addition, sea turtles also play an important role in ecotourism. Places like Costa Rica, United States, and Australia use sea turtles as a source of income by promoting tourism in areas where they live or nest, offering turtle walks, and selling souvenirs (Campbell, 2003). Since sea turtles act as an important resource for humans, there has been much effort into rehabilitating injured sea turtles and researching them in order to determine better prognostic indicators and courses of treatment. Sea turtles are important to us environmentally and economically, so saving them from going extinct requires the most reliable research and data possible to make that happen

 

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Turtle nesting beach located in Tortuguero, Costa Rica.

RNA and plasma proteins are both potential indicators for overall organismal health, but they can degrade quickly if not properly stored. Plasma protein concentrations in sea turtles can help wildlife veterinarians diagnose a disease and create a proper treatment plan (Gicking et al., 2004). Therefore, measuring plasma proteins in archived samples can indicate when or if a . particular disease developed in sea turtles. In addition, RNA concentrations and quality are good indicators of general health. High ratios of RNA/DNA has shown indications of increased cellular protein synthesis along with increased growth potential which means the sea turtle is growing properly (Vieira et al., 2014). However, in order to use archived samples to accurately track health indicators such as plasma proteins and RNA, it is vital to know if storage conditions allowed degradation of these molecules.

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Whole blood tubes used for RNA analysis.

This study aims to investigate RNA and plasma protein stability at different temperature treatments over periods of time. Samples will be maintained in favorable conditions along with unfavorable conditions to analyze the difference between the qualities. By knowing what happens on a molecular level to blood when storage conditions go wrong, we hope to eliminate the use of low quality samples used in research. Freezers malfunction, people forget to put samples away, and blood may not be put in the proper place so the results of this study will become a reference to those researchers who experience these tragedies.

I would like to thank Dr. Jennifer Lynch, Jennifer Trevillian, and Jennifer Ness with the National Institute of Standards and Technology for being my supportive and awesome mentors. This project was made possible by the samples collected by Dr. Michael Arendt and the funding from the National Science Foundation (NSF DBI-1757899) supported by the Fort Johnson REU program.

References:

Campbell L. 2003. Contemporary culture, use, and conservation of sea turtles. In: Lutz PL, Musick JA, and Wyneken J (Eds). The biology of sea turtles, volume 2. Boca Raton, FL:   CRC Press.

Gicking JC, Foley AM, Harr KE, Raskin RE, Jacobson E. 2004. Plasma protein electrophoresis of the atlantic loggerhead sea turtle, Caretta caretta. Herpetological Medicine and Surgery 14:13-18.

McClenachan L, Jackson JBC, Newman MJH. 2006. Conservation implications of historic sea turtle nesting beach loss. Front Ecol Environ 4:290-296.

Vieira S, Martins S, Hawkes LA, Marco A, Teodosio MA. 2014. Biochemical indices and life traits of loggerhead turtles (Caretta caretta) from cape verde islands. PLoS ONE 9:e112181.