Following Deepwater Horizon, there was concern about how the oil spill might affect marine life. Since then, scientists have learned more about how polycyclic aromatic hydrocarbons (PAHs) affect marine organisms, especially commercially and recreationally important fisheries. For example, they found that that exposure to PAHs during a fish’s early life stages (embryo and larvae) can induce sublethal impacts, such as reduced cardiac function, that affect the organism’s overall fitness and health.

Fabrizio Bonatesta is contributing to this research by conducting genetic analyses on oil-exposed zebrafish embryos to assess effects on kidney development and function. “Although a freshwater fish, the zebrafish represents an excellent model for this study because the normal development of the zebrafish kidney is well-characterized,” Fabrizio explained. “We plan to follow-up with similar studies on ecologically and economically relevant species native to the Gulf of Mexico coast, such as red drum.”

Fabrizio is a Ph.D. student with the University of North Texas’s Department of Biological Sciences and a GoMRI Scholar with Relationship of Effects of Cardiac Outcomes in Fish for Validation of Ecological Risk II (RECOVER II).

His Path

Fabrizio grew up in Brindisi, Italy, a small port town where he often spent his free time scuba diving, snorkeling, and enjoying the natural beauty of the beach. Due to its strategic location on the Italian Peninsula and Adriatic Sea, Brindisi is now a popular location for industrial businesses, including chemical and petroleum industries. Despite the economic swell, the influx of these businesses has affected the area’s coastal environment and its residents. “Over the years, I’ve witnessed multiple beached marine mammals and marine fauna degradation possibly related to anthropogenic impacts on the Adriatic Sea ecosystem,” Fabrizio said. “These damages to the marine habitat I hold so close to my heart motivated me to improve my understanding of the circumstances harming the Brindisi coast.”

Fabrizio completed dual undergraduate degrees in biology and marine science at the University of Miami, where he developed a strong foundation in aquatic toxicology and a broad understanding of marine ecosystems. As he anticipated graduate studies, Fabrizio toured the university’s Rosenstiel School of Marine and Atmospheric Science and chatted briefly with Dr. Edward Mager, who was an assistant researcher at the time. Later, when Fabrizio applied to graduate school, he learned that Dr. Mager was now at the University of North Texas and assembling his lab team. Fabrizio reached out and was surprised that Dr. Mager remembered their brief conversation, which led to Fabrizio joining Dr. Mager’s team as his first graduate student and pursuing an environmental science degree with a toxicology focus. “I feel that achieving this degree will allow me to maximize the contributions I can make to preserve the aquatic environment,” said Fabrizio. “If I can better understand the impact that toxicants are having on the environment, I will be able to help develop solutions to improve the quality of aquatic life in Brindisi and other regions.”

His Work

Fabrizio conducts transcriptomics studies using early life stage zebrafish, which previous research showed that exposure to Deepwater Horizon oil may alter or impede transcription related to kidney health. Transcription, the important first step of DNA gene expression, occurs when a DNA segment is copied into RNA and encodes at least one gene. “The kidney is an osmoregulatory and excretory organ found in vertebrates, including fish, that controls the internal solute concentration and helps excrete waste products,” said Fabrizio. “Due to its vital physiological functions, any potential negative outcome to the kidney’s development and functions could have adverse impacts on the organism potentially leading to mortality.”

Fabrizio exposes zebrafish embryos to a water-crude oil mixture (at concentrations similar to those observed during Deepwater Horizon), isolates their RNA, and quantifies differences in gene expression using quantitative polymerase chain reaction (qPCR) compared to controls. So far, he and his colleagues have analyzed 15 target genes (3 genes selected based on previous mahi transcriptomic results and 12 hypothesis-driven genes), including their various transcription factors, signaling proteins, and structural and functional proteins involved in kidney development.

Although Fabrizio is still analyzing the collected data, he observed that exposed zebrafish embryos exhibited significant changes in transcription factors and structural and functional proteins compared to controls. The transcription factors tended to exhibit decreased mRNA expression, while functional and structural proteins related to kidney development tended to exhibit increased mRNA expression.

Fabrizio is also using immunohistochemistry techniques to examine zebrafish kidney morphology. Using an antibody against sodium-potassium adenosine triphosphatase (a transporter enzyme highly expressed in the kidney), he generates florescent staining within the kidneys. Then, he examines the kidney’s structure using a fluorescence microscope to see if there are morphological defects, which could suggest possible direct or indirect impacts from oil exposure.

The next phase of Fabrizio’s research will examine how changing salinity concurrent with oil exposure affects kidney function by subjecting oil-exposed fish to salinity transfer challenges (exposure to abrupt salinity changes). “The Gulf of Mexico coast is characterized by estuaries and brackish waters, where the salt concentration frequently fluctuates,” he said. “These changes might represent a stress to the fishes inhabiting these waters. If it is not compensated for, the salinity stress may interfere with the organism’s physiological homeostasis and various biological processes, which could be lethal to some.”

His Learning

Working with Dr. Mager taught Fabrizio that scientific research requires a meticulous approach and the ability to troubleshoot problems as they arise. Dr. Mager’s work ethic and enthusiasm for their research greatly strengthened Fabrizio’s dedication to his own research goals. “It is my duty as a scientist to review previous research papers and study their methods to improve my own [methods],” said Fabrizio. “I enjoy the process of uncovering new information and bonding with my peers over the review process.”

Fabrizio said that GoMRI gives scientists who are interested in researching the Gulf of Mexico ecosystem an opportunity to collaborate. “Being able to connect and share our findings is crucial in the scientific world,” he said. “The cooperation of all the people involved with GoMRI research can provide important insights to prevent future spills and restore the environment.”

Fabrizio would like to work with a private company in the United States before returning to Italy. Eventually, he hopes to apply his education towards creating an Italian organization of scientists from a broad range of fields. He envisions that the organization would help define environmental problems, inform public discussion surrounding those issues, and support solutions improving environmental conditions and related affects on human health.

Praise for Fabrizio

Dr. Mager describes Fabrizio as a quick-learner and a dedicated worker whose independence exceeds that of other students at similar stages in their research. “Fabrizio is very professional, considerate, insightful, and a true team-player. It is a pleasure to have him in my lab,” he said. “I believe he is a very promising young environmental scientist, and I look forward to helping him progress through his Ph.D. and observe his career beyond.”

The GoMRI community embraces bright and dedicated students like Fabrizio Bonatesta 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 RECOVER 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 http://gulfresearchinitiative.org/.

© Copyright 2010-2019 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).

Many fish that were exposed to Deepwater Horizon oil survived; however, they may have experienced later-in-life impacts that affected their ability to survive longer than fish that did not experience oil exposure. Alexis Khursigara investigates if oil-induced latent effects in red drum (Sciaenops ocellatus) alters behavior, particularly the ability to learn and compete with other fish, which are critical to fish survival. Her research addresses hypotheses concerning sublethal effects of oil and may help inform long term population health and fishery management.

Alexis is a Ph.D. student with the University of Texas at Austin’s Marine Science Institute and a GoMRI Scholar with the Relationship of Effects of Cardiac Outcomes in Fish for Validation of Ecological Risk (RECOVER) consortium.

Her Path

Alexis’s parents introduced her to the scientific world at a young age. She spent her childhood summers in her father and step-mother’s neuroscience labs, working with Schwann (neurilemma) cells, helping care for mice and rats, and conducting her own chemical interaction mini-experiments using milk powder and dry ice. Her mother sparked her interest in fish and marine science through trips to the aquarium, where Alexis would spend hours.

Alexis later completed undergraduate and master’s degrees in secondary educational biology at Fairfield University and enrolled in the University of Texas at Austin’s marine science doctoral program. Wanting to focus on how environmental stressors affect fish physiology and behavior, she joined Dr. Andrew Esbaugh’s fish lab researching how oil-induced changes in fish physiology and behavior affect their performance.

“My love for the ocean, fish, and the environment are really what connects me to my research. I love being able to study how human activity impacts our environments and how fish react to those changes,” said Alexis. “I’ve been very fortunate to have parents and people in my life who have always encouraged me to pursue my passions.”

Her Work

Alexis examines the performance of oil-exposed fish compared to control fish as they compete for food and dominance, and conducts long-term group experiments where growth indicates competitive success.

In the one-on-one trials, fish are individually fitted with an elastomer and acclimated in a tank without food for 48 hours. She then observed each fish for 15 minutes, twice a day, for 5 days recording their location in the tank, food acquisition, and interactions such as attacks or avoidance. She also took images of their fins before and after the trials to assess fin damage caused by attacks from other fish. These metrics provided an overall behavior score; the fish with the highest score was deemed dominant while the lower score was the subordinate fish. In group trials, dominance was primarily assessed through specific growth rate (how much a fish grew per day). Fish that obtained more food and had a faster growth rate were considered dominant. In both scenarios, she found that oil-exposed fish tended to be subordinate when there were limited resources.

Alexis is currently conducting week-long fish experiments using a maze with rewards such as food or another fish at the end to understand how oil-induced changes in neurological function may alter fish behavior. She measures fish’s learning ability by observing the amount of time, distance swam, and number of wrong turns each fish takes to reach the reward. She also conducts trials on fish traits such as boldness or sociability to determine changes in a fish’s personality. While these trials are still being conducted, early results indicate that sociability-related behavior changes occur following oil exposure. “While these tests themselves don’t tell us the state of a fish’s neurological function, shifts in performance in these tests can indicate altered function,” explained Alexis. “For example, if oil-exposed fish aren’t able to learn at the same rate as unexposed fish or if a fish demonstrates certain personality traits before exposure that change after exposure, it may indicate some neurological impairment.”

Alexis is currently considering her results in the context of findings from other RECOVER researchers. So far, she has noticed that aerobic scope is an important factor in dominance hierarchies and that fish with a higher aerobic scope (the difference between minimum and maximum oxygen consumption rate) often become dominant. She explained that when oil reduces an individual fish’s aerobic scope, it also reduces their ability to compete in social settings, predisposing them to social subordination. “A major reason for my investigation into personality and learning behaviors came from transcriptomics data run by another group in the consortium,” said Alexis. “They saw that pathways related to neurological and cognitive function were altered following oil exposure, so we’re using personality and learning behaviors to understand how.”

Her Learning

Working in Esbaugh’s lab taught Alexis communication and collaboration skills and introduced her to new techniques that made her a better researcher. Before joining Esbaugh’s team, she felt hesitant about conducting molecular research due to lack of experience and training. However, his encouragement and insistence on learning molecular techniques eventually led her to a project examining oil-exposed and control fish’s gene expression rates of corticoid receptors as indicators of chronic stress. “I spent months trying to design a primer that would work with our species. Finally, after weeks of failure, I finally found primers that worked,” recalled Alexis. “While this was a really big moment for my research, it was also a big moment for me personally. It showed me that if I get past my hesitations about what I can and can’t do, I can open myself up to some really cool things.”

A memorable experience for Alexis was working with her University of Texas community following Hurricane Harvey. Although the storm caused a lot of damage, personal loss, and hard times, she grew closer to others in her lab and her department. She also learned how to recover should another storm hit – a very real possibility when working in coastal facilities. “People were helping others pack up their stuff, getting rid of destroyed belongings, finding new places to live, and replacing lost items,” she said. “We’ve always had a strong sense of community here at the University of Texas Marine Science Institute (UTMSI), but going through something like that made us even closer. I’m incredibly grateful for the leadership and guidance I received not only from my advisor, but the faculty and administration at UTMSI in getting through that difficult time.”

Her Future

Alexis hopes to enter a post-doc position after graduating and find a university position that would allow her to teach and run a research lab. She offered some advice for students considering a career in science: love what you do, build a strong science base, take advantage of any and all resources and opportunities, and, most importantly, have a strong support system.

Praise for Alexis

Dr. Esbaugh described Alexis as a bright and hard-working student who is eager to try new projects and methods and takes constructive criticism well. He praised her contributions to his lab and to the RECOVER consortium, particularly their research direction. “Her project started as an intuitive ecological extension of a well-known oil effect in fish – cardiac impairment – but through her own observation and initiative, it moved into a new and exciting direction,” he said. “She’s been the driving force for an area of research that our entire consortium is embracing. As a student, I could not have asked for more.”

The GoMRI community embraces bright and dedicated students like Alexis Khursigara 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 RECOVER website to learn more about their work.

By Stephanie Ellis and Nilde Maggie Dannreuther. Contact sellis@ngi.msstate.edu for questions or comments.

************

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).

Laboratory studies at the University of Miami suggest that exposure to Deepwater Horizon oil may have negatively affected heart function in mahi-mahi, reducing their ability to swim efficiently. Lela Schlenker is expanding that research to investigate if and how oil exposure alters the way mahi-mahi migrate and respond to predators and prey in the wild. She conducts her research using different approaches: one focusing on mahi-mahi’s ability to smell and another that uses satellite tagging to monitor mahi-mahi’s behavior after encountering oil.

Lela is a Ph.D. student with the University of Miami’s Rosenstiel School of Marine and Atmospheric Science and a GoMRI Scholar with RECOVER.

Her Path

Lela began her environmental undergraduate studies at Smith College but wasn’t sure if she felt more drawn to terrestrial biology or marine science. A study-away maritime science program with the Williams-Mystic Program gave her the opportunity to experience marine science hands-on and inspired her to continue on that path. She designed an independent project for the course that involved collecting samples aboard a commercial fishing vessel. “It was an eye-opening experience to see all the amazing critters that we were catching and getting to talk to fishermen who have an incredible knowledge base and skillset. The intersection of the biological and human aspects of the fishing really struck me,” said Lela.

The experience inspired Lela to pursue various fisheries-based jobs after completing her undergraduate degree. One of these jobs brought her to the Dauphin Island Sea Lab just months after the Deepwater Horizon incident occurred. Seeing the spill’s initial effects first-hand inspired her to someday explore the oil’s impacts on Gulf ecology and fishing communities. While completing a master’s degree in fisheries science at the College of William and Mary, she learned about Dr. Martin Grosell’s mahi-mahi research at the University of Miami and contacted him about a possible student research position. Grosell thought Lela would be a good fit for his lab; however, he couldn’t hire her unless his proposed RECOVER project received GoMRI funding.

“Whether or not I could come to Rosenstiel and do my Ph.D. completely hinged on that grant,” said Lela. “I got an email from him right after the grant came in asking me to come for an interview. I wouldn’t be here if it weren’t for GoMRI funding. GoMRI has been instrumental in my career – having funding like this is a really rare and exciting opportunity!”

Her Work

Lela assesses how oil exposure affects mahi-mahi’s ability to smell using an electro-olfactogram. She sedates the fish and removes a thin layer of skin from the nostril (septum) to uncover the olfactory rosette – finger-like projections covered in neurons. The fish is fitted with highly conductive electrodes that attach to the animal’s skin and on the rosette. She then delivers seawater with different scents (unscented, prey-scented, and predator-scented) directly to the rosette and measures voltage changes in the neurons in response to each smell. Greater changes in voltage indicate a stronger neurological response and, therefore, a stronger ability to detect the scent. She then dilutes the scent incrementally to determine how faint the smell must be before the fish can no longer detect it.

The next phase of Lela’s olfactory research will expose mahi-mahi to oil and observe if and how their sense of smell changes compared to control fish. A diminished ability to track prey and sense predators via smell could have significant implications for the fish’s survival, migration patterns, and spawning behavior.

Lela will also be conducting satellite tagging experiments that build upon previous tagging field experiments. This summer, her team will capture wild mahi-mahi, rest them in water tanks containing seawater or seawater plus oil, fit the fish with satellite-enabled tags, and release them from the same location. The tags will relay temperature, depth, light level, and location information back to the researchers, who will use it to identify differences in swimming speed, spawning behavior, and migration patterns between the control and oil-exposed fish. “Our tagging research will help us understand how [previous findings that oil affects mahi-mahi physiology] would manifest in the wild and, if the fish were exposed to oil during a spill, how they would cope and what recovery may or may not look like,” she said.

Her Learning

The greatest lesson that Lela has learned working alongside Grosell is the importance of being an optimist and making bold choices. Previous studies documenting mahi-mahi behavior experienced many challenges from limited resources to difficulties handling and tagging the wild fish, something Lela was aware of when her team’s research began. She was inspired by Grosell’s determination to improve the research methods to collect better data and include oil as an additional variable. “It was a little scary when he told me we were going to take this thing that no one else has been able to do and then make it harder by adding the oil,” said Lela. “It was a good lesson that sometimes you just have to be bold and go for it and if you can figure out a way to make it happen, then you’re going to conduct exciting research that no one else has been able to do.”

Her Future

Lela hopes to continue working in a collaborative research environment after graduation, particularly in a position that also allows her to teach and spark the passion she feels for science in others. She advises students considering a scientific career to explore different avenues before entering graduate school to help solidify which aspects of science they want to pursue. “Taking the time to do different jobs and figure out exactly what you like about scientific research can be really helpful,” said Lela. “It’s not bad to try a lot of different things, especially when you’re in college or right out of college. There’s a lot of different experiences out there, and you never really know where things will lead.”

Praise for Lela

Dr. Grosell commended Lela’s unique dissertation research, which spans several levels of biological organization and offers a refreshing, integrative view of oil impacts on large marine pelagic organisms. He added that she previously led a research cruise and will act as lead scientist for an upcoming cruise in the Gulf of Mexico this summer. “As lead scientist, Lela demonstrates a rare talent for leadership and pursuing challenging directions while promoting a supportive and collegial atmosphere,” said Grosell. “I am grateful to have Lela in my group and continue to learn from her.”

The GoMRI community embraces bright and dedicated students like Lela Schlenker 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 RECOVER website to learn more about their work.

************

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).