Phytoplankton and bacteria in the northern Gulf of Mexico interact closely at the food web base and provide vital food and nutrients to marine life at higher trophic levels. During the Deepwater Horizon incident, these pervasive organisms played an important role in oil bioremediation before and after the application of chemical dispersants, which broke up surface slicks into smaller droplets and enhanced microbial degradation. Samantha “Sam” Setta, who recently completed her master’s degree, used molecular-level techniques to learn how oil and dispersant exposure affects the abundance of and interactions between Gulf bacteria and phytoplankton.
Sam recently graduated from the Texas A&M University at Galveston’s Marine Biology Department and was a GoMRI Scholar with the Aggregation and Degradation of Dispersants and Oil by Microbial Exopolymers (ADDOMEx) consortium.
Her Path
Sam’s interest in a scientific career was sparked by a high school aquatic science class that emphasized marine science and conservation. As a freshman at the University of Texas at Austin, she changed her major from chemistry to biology to physics and ultimately settled on marine biology with a focus on freshwater.
“Growing up in Austin, I was surrounded by parks, lakes, and natural springs that influenced my thinking of the world and led me to an interest in conservation, especially water conservation,” said Sam. She enhanced her undergraduate education by conducting research in Mexico and working with a graduate student at the university’s Marine Science Institute, which provided work experience and insight into graduate student life.
However, Sam was still unsure about pursuing a graduate degree and decided to explore different fields to pinpoint her passion. She worked as a research technician on algal biofuel in Texas and later as a research associate with Dr. Brian Roberts studying the Deepwater Horizon’s effects on Louisiana salt marsh vegetation and biogeochemistry. The oil spill research inspired her to pursue graduate school, and she began her master’s studies with Dr. Antonietta Quigg at Texas A&M University at Galveston investigating the spill’s effects on microbial community composition.
Her Work
Phytoplankton are microscopic photosynthesizers that transform atmospheric carbon dioxide into food for grazers and other microscopic heterotrophs. Bacteria then recycle the used carbon into a form that heterotrophs can eat again, starting a microbial loop of recycling and reusing organic carbon. Sam’s research as a master’s student was to learn how oil and dispersant may have affected these microbial interactions.
Sam and her colleagues incubated Gulf of Mexico microbial communities with different oil and oil plus dispersant concentrations in large tanks that mimicked conditions around the spill area. She extracted DNA from bacteria in tank water samples, amplified identifiable DNA regions using polymerase chain reactions, and measured and recorded nucleotides using DNA sequencing techniques. Sam is using the sequencing data to characterize the composition of bacterial and phytoplankton communities under different exposure scenarios.
Samantha is now a Ph.D. student at the University of Rhode Island and continues her oil spill research in her free time. She is currently analyzing the bacteria-phytoplankton interactions for each exposure using a network analysis that correlates community composition over time under different oil and dispersant exposures. Her findings will ultimately identify taxa that play a key role in oil bioremediation, their correlation with certain phytoplankton and other eukaryotic organisms, and how oil and dispersant exposure change these taxa.
“Highlighting the key players that respond to spilled oil will help better direct future studies and oil spill mitigation,” explained Sam. “This information can be used to target key taxa in other laboratory studies and provide more information to policy makers on the pros and cons of using dispersant in the event of an oil spill.”
Her Learning
Sam’s research provided her with frequent experience working in a collaborative environment. She described her time with Dr. Quigg’s group as encouraging and enriching, “I found that the tank experiments we did once a year with the entire research consortium were the best time to collaborate and get to know the research everyone else was doing as part of the project. Everyone involved in the ADDOMEx consortium has been very supportive.”
Her Future
Sam recently began Ph.D. studies in oceanography at the University of Rhode Island Graduate School of Oceanography. She suggests that students use their time in graduate school to learn where their interests lie before committing to a specific scientific career.
Praise for Samantha
Dr. Quigg described Sam as a student who is smart, determined, and fun to work with. She explained that despite Sam’s complex master’s research for the ADDOMEx consortium and her tremendous determination and ability to work well with others made her project a success. “Sam was one of those students who you meet and immediately know they will be both a great scientist and colleague,” said Quigg. “Her research required her to work on the cutting edge of a variety of disciplines, and she rose to the challenge and even finished her master’s in two years. I look forward to watching her continue to develop her craft as she starts her Ph.D. at the University of Rhode Island this fall.”
The GoMRI community embraces bright and dedicated students like Samantha Setta and their important contributions. The GoMRI Scholars Program recognizes graduate students whose work focuses on GoMRI-funded projects and builds community for the next generation of ocean science professionals. Visit the ADDOMEx website to learn more about their work.
By Stephanie Ellis and Nilde Maggie Dannreuther. Contact sellis@ngi.msstate.edu for questions or comments.
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The Gulf of Mexico Research Initiative (GoMRI) is a 10-year independent research program established to study the effect, and the potential associated impact, of hydrocarbon releases on the environment and public health, as well as to develop improved spill mitigation, oil detection, characterization and remediation technologies. An independent and academic 20-member Research Board makes the funding and research direction decisions to ensure the intellectual quality, effectiveness and academic independence of the GoMRI research. All research data, findings and publications will be made publicly available. The program was established through a $500 million financial commitment from BP. For more information, visit https://gulfresearchinitiative.org/.
© Copyright 2010-2018 Gulf of Mexico Research Initiative (GoMRI) – All Rights Reserved. Redistribution is encouraged with acknowledgement to the Gulf of Mexico Research Initiative (GoMRI). Please credit images and/or videos as done in each article. Questions? Contact web-content editor Nilde “Maggie” Dannreuther, Northern Gulf Institute, Mississippi State University (maggied@ngi.msstate.edu).
