Professor and Principal Investigator

sepulvada holding a fish

Dr. Maria S. Sepúlveda

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Dr. Maria Sepúlveda’s main area of research is ecotoxicology. Over the last two decades, she has conducted extensive research evaluating the sublethal effects of a wide-range of environmental contaminants on the physiology of numerous terrestrial and aquatic species. She earned a Doctorate in Veterinary Medicine degree from Universidad de Chile, Santiago, Chile; her MS from University of Florida, Gainesville, Florida (Wildlife Ecology); and her PhD from the same University (Veterinary Sciences/Toxicology). Dr. Sepúlveda’s research focuses on understanding the sublethal effects of legacy and emerging pollutants to fish and wildlife. Her laboratory uses a diverse number of animal models and techniques to advance the field of aquatic toxicology.

Research Assistant Faculty and Principal Investigator

Hoskins holding a fish

Tyler Hoskins

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Ty obtained his B.S. in Biology from Butler University in Indianapolis and his Ph.D. in Ecology, Evolution, and Environmental Biology from Miami University, in Oxford OH. He is studying accumulation and effects of per- and polyfluorinated alkyl substances (PFAS) on aquatic and estuarine wildlife. Current projects include establishment of PFAS toxicity reference values for amphibians, effects of PFAS on brain accumulation and neurotransmission, assessment of biosolid-derived PFAS in farm pond ecosystems, evaluation of PFAS toxicity to blood midges with emphasis on developing QSAR models for hemoglobin binding, and in vitro metabolism of precursor PFAS in aquatic vertebrates and invertebrates.


Laboratory Managers

Jennifer holding a redear turtle.

Jennifer McAdams

Jennifer manages the Aquatic Sciences laboratories in the Purdue Forestry building. Her current research focus in the Sepulveda lab is the structural effect of PFAS on human hemoglobin molecules. She previously worked as a lab manager in a behavioral neuroscience lab studying vagal PNS innervation and the therapeutic effects of vagus nerve stimulation.

Shelby holding hellbender next to a tank.

Shelby Royal

Shelby is the lab manager at the Wildlife Ecology Research Facility (WERF). She graduated with her bachelor’s and master’s in wildlife science from Purdue University. Shelby oversees the ecotoxicology research conducted at WERF; as well as hellbender conservation research. She assists with experimental design, undergraduate and graduate mentoring, and teaching undergraduate habitat management and techniques.

Nathan by large plant standing in outside garden.

Nathan Mak

Nathan received his B.S. in Biological Sciences and Entomology from Cornell University in 2022. His work focuses on the effects of stream water temperature and industrial effluent on fish stress and molecular responses.

Graduate Students

Colleen in the beach.

Colleen Geib

Colleen obtained her B.S. in Environmental Health, a M.S. in Public Health, and is an Registered Nurse. As a nurse and seasoned public health professional, she is curiously driven to learn about environmental exposures and study the impact of toxicants in our environment resulting in increased rates of disease or pathologies in both aquatic life and humans. Colleen was accepted into Purdue’s competitive Ecological Sciences and Engineering (ESE) interdisciplinary graduate program. She is thrilled to join the Sepulveda-Hoskins lab, shift gears, and begin her PhD journey to study PFAS bioaccumulation and trophic transfer in farm ponds with a focus on human health implications.

Undergraduate Students

Sophia's headshot

Sophia Horn

Sophia is a junior majoring in Biology at Purdue’s College of Science. She leads a genetic sexing project with the purpose of adding sex as a covariate to our ecotoxicology projects involving the species Xenopus Laevis.

Emma Engel

Emma is a senior majoring in Aquatic Sciences with a concentration in Marine and Freshwater Biology. She also has minors in Wildlife Science and Environmental Policy & Politics. She has been a member of the genetic sexing team in the past and aided in PFAS research on amphibians including the establishment of toxicity reference values. She currently works on maintenance of mesocosms as part of the biosolids project and assists in husbandry and exposure of the midge colony.

Hallie Jackson

Hallie is a junior majoring in Ecology with minors in Chemistry and Wildlife Sciences. Hallie is working on a project examining gene expression in fathead minnows exposed to an oil refinery effluent. She is also helping on a project that is genetically sexing Xenopus laevis to examine the importance of sex on toxicity responses.

Jenna Shoonmaker

Jenna is a junior at Purdue University majoring in biochemistry and minoring in wildlife science, bioinformatics, and Spanish. She started in the Sepulveda lab in the spring of 2023 but took the fall semester off to study abroad in Ireland. In the future, Jenna plans to earn a PhD in ecotoxicology and continue her research.

Olivia Zaragoza

Olivia is a junior majoring in Natural Resources and Environmental Science with a focus on marine biology and sustainability. She is currently helping with a project on midges and the effects of Per- and polyfluoroalkyl substances (PFAS) exposure to discover more about aquatic ecotoxicology.