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About Us

About us

BS Chemistry

University of Paris V

MS Geochemistry

University of Paris VII/IPGP

PHD Oceanography

University of Connecticut

Postdoc Environmental Health

Harvard School of Public Health

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Amina T. Schartup

Amina Schartup is an Associate Professor at the Scripps Institution of Oceanography (SIO). Before joining SIO in 2019, Amina was a Research Associate at the Harvard School of Public Health and the Harvard School of Engineering and Applied Sciences. Amina was also a 2017-2019 AAAS Science and Technology Policy Fellow at the NSF Office of Polar Program–Arctic Section, where she developed a federal guidance document on pursuing ethical research in the Arctic

Lab manager
Iris Kubler-Dudgeon

BS Mathematics, Applied Sciences 

University of California San Diego


Iris Kübler-Dudgeon is the Schartup lab manager. She completed a BS at UC San Diego majoring in Mathematics, Applied Science with the sciences of Chemistry and Oceanography. She grew up in Southern California, but spends part of each year on an island in the Gulf of Maine, where she has previously been a part of the Swans Island Long Term Research in Environmental Biology. Iris joined the Schartup Lab through the California Current Ecosystem Long Term Ecological Research Program REU. At UCSD Iris plays on the Dragon Coalition Women’s Ultimate Frisbee team.

Johannes West

BS in Geology
MS in Geosciences
PhD in Environmental Science

Stockholm University, Sweden

Johannes West is a biogeochemist studying element cycles with a focus on mercury in aquatic environments. He received a Ph.D. from Stockholm University, Sweden, in 2022, and joined the Schartup lab in 2023 as an SIO postdoctoral fellow. Johannes develops and applies methods using stable isotopes, atoms of the same element but with different masses, to study natural processes. Using this approach, he learns how mercury transforms between its inorganic and methylated forms, crucial for its toxicity and availability to living organisms. Johannes’s dissertation focused on dimethylmercury, a form of mercury that is challenging to work with since it is both gaseous and highly toxic. He currently uses the skills he acquired during his Ph.D. work to develop new experimental protocols and methods for measuring dimethylmercury. Outside of work, Johannes plays the accordion and enjoys sports such as running and climbing. ResearchGate Email

About us
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Hannah Adams

BS Chemistry

BA Environmental Studies

University of Southern California


MS Earth Science

Scripps Institution of Oceanography

Hannah Adams is a PhD Candidate that joined the lab in August 2020. Her research focuses on understanding the role that dimethylmercury plays in the marine mercury biogeochemical cycle. Prior to joining the Schartup Lab, Hannah was a Research Assistant at Texas A&M University in Jessica Fitzsimmons’ lab studying trace metals in Galveston Bay, Texas and in the Gulf of Mexico. Before that, she completed her undergraduate studies at the University of Southern California, graduating in 2019 with a B.S. in Chemistry and a B.A. in Environmental Studies. In her free time, Hannah likes to play kickball, read, travel, and scuba dive. Check out Hannah’s publications on Google Scholar

Cathryn Sephus

BS/MS Molecular and Cellular Biology

Minor in Astronomical Studies

University of Arizona


Cathryn Sephus is a PhD student in the Marine Chemistry and Geochemistry curricular group at the Scripps Institution of Oceanography. Her research interests center on microbial evolution and molecular adaptations used to survive heavy metal exposures in hypersaline environments. Her current work integrates chemistry with biology and bioinformatics to investigate how microbes can transform or utilize mercury and arsenic compounds to survive diverse hypersaline systems that serve as analogs to environments in Earth’s past and other planetary bodies. By studying the interactions between biology and metals in these environments, she aims to understand the limits and potentials of life on Earth and elsewhere in the universe.
Cathryn completed her master’s degree and bachelor’s degree (with honors) in Molecular and Cellular Biology at the University of Arizona in 2021 and 2019, respectively. There, her research centered on astrochemistry and astrobiology with an emphasis on understanding how chemical and planetary environments affect habitability and evolution.
In her free time, she loves to travel, read, paint, and make pottery.

Google Scholar

Erik Paulson

BS Biology

BA Chemistry

MS Chemistry

University of North Carolina Wilmington


Erik Paulson is a PhD student from North Carolina who is currently exploring the interactions of phytoplankton and mercury. As an undergraduate at UNC Wilmington, he did research in a variety of fields, including biochemistry, comparative physiology, and chemical education. There, he earned a B.S. in Biology, a B.A. in Chemistry, and a M.S. in Chemistry with a thesis in chemical education. His love for the ocean and interdisciplinary science inspired the trace metal research he’s pursuing at SIO. In his free time, Erik likes to surf and enjoy the outdoors.

Roland Ovbiebo

BTech Marine Science and Technology

The Federal University of Technology Akure, Nigeria


Roland Ovbiebo is a PhD student in the Marine Chemistry and Geochemistry curricular group. He’s originally from Nigeria where he got his bachelor’s degree in marine science and technology from the Federal University of Technology Akure. As part of his undergraduate final year project, he worked on the low-tide seasonal variations of physicochemical properties and heavy metal concentrations in the Benin River Estuary, Gulf of Guinea. He went further to Woods Hole Oceanographic Institution as a guest student to learn how to use Python programming language to analyze satellite data in studying physical and chemical processes in the ocean. Currently, he works on the biogeochemical cycling of mercury. He is building a numerical computer model to study the chemical, biological, and physical transformation process of mercury in the estuary, a region where fresh river water meets the salty ocean water. In his model, he considers how the mixing of river freshwater and ocean saltwater impacts the transformation of mercury in this dynamic environment to better estimate the amount of mercury exported to the ocean. In his free time, Roland loves watching football (not American), biking, swimming, and traveling.


Maya Chari, Summer intern (SURF program)

Ana Carrick-Gonzales, Intern (McNair program)

Iris Kübler-Dudgeon, Summer intern (CCE REU program)

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