Hannah M. Adams, Ph.D.
Understanding mercury cycling in a changing ocean
NSF Postdoctoral Fellow · Scripps Institution of Oceanography, UC San Diego
I'm a biogeochemist interested in understanding how human activity reshapes natural cycling of trace metals, with a focus on mercury in coastal and open ocean environments. Mercury has been my primary focus, but I'm interested in discussing trace metal cycling, coastal biogeochemistry, microbial drivers of biogeochemical cycling, or the intersection between environmental chemistry, climate, and policy. My work combines analytical chemistry, microbial ecology, and modeling to resolve overlooked chemical species and identify what drives their transformation. I completed my Ph.D. in Earth Sciences at Scripps in 2025, where I continue this work today as an NSF Postdoctoral Fellow.
Trace metal biogeochemistry in a changing ocean
Marine mercury cycling contains major unresolved gaps, it speciates into forms that trace physical, chemical, and biological processes, carries a clear anthropogenic signal, and has direct consequences for human health through seafood exposure. My work draws on analytical chemistry, microbial ecology, and modeling to close those gaps, building a framework that extends to trace metal biogeochemistry more broadly. My research fits into several themes, detailed below.
Resolving overlooked chemical species and transformation pathways
Dimethylmercury (DMHg) is the most understudied species in the marine mercury cycle, leaving it poorly constrained in global mercury budgets. Through field sampling and mass budget modeling, my work in the California Current System identified DMHg as a major, previously underappreciated source of monomethylmercury, through upwelling and subsequent demethylation in surface waters.
Identifying microbial drivers of trace metal biogeochemistry
My current research is investigating microbial drivers of methylated mercury formation in surface waters within the California Current System, combining time series sampling, field sampling, multi-'omics, microbial community profiling, and isotopically labeled tracer incubation studies to evaluate rates and microbial mechanisms.
Modeling systems-level fluxes and predictive insights
Field measurements become mechanistically meaningful once they're placed in a systems-level model. I use mass-budget, machine learning, and predictive modeling approaches to trace mercury transformations, predict climate-driven changes, and evaluate microbial community dynamics across scales and marine systems.
Evaluating anthropogenic change against natural variability
Evaluating anthropogenic impacts against the backdrop of natural variability is essential for understanding whether environmental policies are effective and for anticipating how trace metal cycling will respond in a changing climate. My work under this theme spans the Scripps Pier time series, a time series of sediment heavy metal concentrations in Galveston Bay, Texas, and examining Hg sources within a Greenland glacial fjord system.
Core Projects
The Scripps Pier Mercury Speciation Time Series
A high-resolution record of Hg⁰, Hg(II), MMHg, and DMHg at Scripps Pier, paired with 16S/18S microbial community profiling, physical parameters, and multi-omics. Long-term monitoring at this site has revealed significant variability in Hg speciation, which is the basis for in-depth mechanistic work in this system.
California Current System field studies
Three studies built from oceanographic sampling aboard the R/V Roger Revelle and R/V Sally Ride (2023, 2024, and 2026), tracing how upwelling drives mercury speciation and biogeochemical cycling in one of the ocean's most productive systems. Major findings from this work include establishing DMHg as a major source of MMHg in surface waters, and showing that upwelling enhances mercury particle scavenging. Studying this system has included field-based sampling, mass budget modeling, and isotopically labeled incubation studies, with new projects including methods development and multi-omics sampling.
Looking ahead
I am interested in establishing new coastal time series, examining drivers of variability and methylation processes, and extending this comparative, interdisciplinary approach to other trace metal cycles and ocean basins.
Publications and presentations
Six peer-reviewed papers published or in press, plus a selection of conference presentations and invited talks.
Peer-reviewed publications
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Non-refereed & press
Presentations
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Education, appointments, and skills
Education, appointments, grants, field experience, and technical skills. A full CV is available on request.
Education
Selected grants & awards
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Appointments
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Field experience
Technical Skills
Professional memberships
Student-centered teaching and mentorship
My teaching starts by meeting people where they are, builds scientific thinking through scaffolding and active participation, and aims to equip people with scientific literacy and tools for engaging with the world around them.
Teaching experience
Mentorship
Mentees span Applied Math, Marine Biology, Environmental Engineering, and Geosciences, recruited through formal programs — the McNair Scholars Program and NSF GEOPAths — and informal lab recruitment. They've gone on to co-author peer-reviewed papers, present at international conferences, and continue on to graduate school.
Student Evaluations
Official UC San Diego Instructional Assistant evaluations from SIO 3: Life in the Oceans (Summer Session I, 2025) rated instruction 100% positive across all six evaluated categories — instructional methods, coordination with course components, communication, constructive feedback, a welcoming and supportive learning environment, and punctuality — for an average of 4.8 out of 5.
"Office hours, responded to emails, answered any questions I had."
"She was very informative and helpful!"
SIO 30: The Oceans — Guest Lecture, 2026
Guest Lecture Feedback
Feedback from students after a guest lecture and pier tour on Time Series and the Scripps Pier (17 students total).
“The teacher explained the material clearly, was helpful when students had questions, and created a positive learning environment.”
“I like her outgoing teaching style, and she is very passionate.”
“I enjoyed how Dr. Adams wrapped up our lecture with the pier tour and time series activity, because it basically ties in everything that we were learning on Tuesday about time series and actually seeing the equipment in person, and the pier was pretty cool.”
“Everything was explained clearly and there were no points of confusion. All the different pieces of information were put together very well and everything felt cohesive and not like pieces put together with no care.”
“One thing I liked about Dr. Adams' lecture was how organized and well structured she came to our class. She was on point with what her goals and objectives for the class were and I feel she met each and every one of them. I also liked how she took the time to consider if anyone had any questions instead of moving on to her next topic.”
“I loved the fact that content covered in the lecture slides were accompanied by their own associated examples. As a visual learner, I like being able to see diagrams and graphics exemplifying the topic, so breaking these concepts of temporal and spatial environmental sampling into each of their own graphs was really helpful.”
“The slides were very nice and made it easy to follow the spoken lecture and the slides at the same time. It was also organized very well.”
Broadening participation in the ocean sciences
Inside and outside the lab, I am committed to lowering barriers and strengthening belonging in environmental sciences. Below are selected initiatives that I have participated in.
Group Leader & Instructor, 2026
Coastal Ocean Environment Summer School in Nigeria and Ghana (COESSING)
Taught biogeochemistry of the water column to graduate students and faculty in Nigeria, adapting instruction to a wide range of prior technical training and access to resources.
Coordinator, 2021–2025
Scripps Community Outreach for Public Education
Directed operations of a free K–12 and community STEM outreach program, personally leading tours for students, families, and policymakers, and training 100+ volunteers to lead tours themselves.
Co-Founder, 2020–2023
Queer@Scripps
Grew an informal gathering into a formally recognized student organization building community and support networks for LGBTQ+ scientists at Scripps Institution of Oceanography.
Mentor, 2022
Scripps Institution of Oceanography Applicant Support Knowledgebase
Mentored two prospective students from underrepresented backgrounds through the PhD application process. Both went on to pursue graduate education within University of California programs.