Hannah M. Adams
Portrait of Hannah Adams at Scripps Pier, La Jolla, California

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.

hmadams@ucsd.edu Google Scholar LinkedIn ORCID

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.

01

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.

Adams et al. 2024 Cui et al. 2024
02

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.

NSF OCE-PRF 2025–2027
03

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.

Adams et al. 2025 Lindeman et al. 2024 Adams et al. 2024
04

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.

Adams et al. 2025 Lindeman et al. 2024 Mulcan Lopez et al. 2021 Mulcan Lopez et al. 2021

Core Projects

The Scripps Pier Mercury Speciation Time Series

Dec 2020started
2x weeklysampling cadence
5+ yrscontinuous record
3Hg speciation measurements

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.

Adams et al. 2025, Comms Earth & Env.

California Current System field studies

3oceanographic studies
46days at sea
2publications

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.

Adams et al. 2024, ES&T Cui et al. 2024, ES&T

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

2025
Coastal inorganic mercury time series reveals interannual and seasonal variability driven by regional climate factors
Communications Earth & Environment · Adams, H.M., Wu, P., Kübler-Dudgeon, I., Lamborg, C., Bowman, J., Schartup, A.T. doi →
2024
Upwelling enhances mercury particle scavenging in the California Current System
Environmental Science & Technology · Cui, X., Adams, H.M., Stukel, M.R., Song, Y., Schartup, A.T., Lamborg, C.H. doi →
2024
Dimethylmercury as a source of monomethylmercury in a highly productive upwelling system Editors' Choice
Environmental Science & Technology · Adams, H.M., Cui, X., Lamborg, C.H., Schartup, A.T. doi →
2024
Low mercury concentrations in a Greenland glacial fjord attributed to oceanic sources
Communications Earth & Environment · Lindeman, M.R., Straneo, F., Adams, H.M., Nelson, M.J.S., Schartup, A.T. doi →
Show earlier publications (2)
2021
A time-series of heavy metal geochemistry in sediments of Galveston Bay estuary, Texas, 2017–2019
Science of the Total Environment · Mulcan Lopez, A., Fitzsimmons, J.N., Adams, H.M., Dellapenna, T.M., Brandon, A.D. doi →
2021
Lead geochemistry of sediments in Galveston Bay estuary, Texas
Environmental Advances · Mulcan Lopez, A., Brandon, A.D., Ramos, F.C., Fitzsimmons, J.N., Dellapenna, T.M., Adams, H.M. doi →

Non-refereed & press

2025
It takes patience to measure change
Adams, H.M., Schartup, A.T. · Nature Behind the Paper read →
2024
Study illuminates previously unknown ocean mercury pathway
Fox, A. · Scripps Institution of Oceanography news read →

Presentations

2026
Rethinking mercury cycling in the surface ocean: insights from a 5-year time series at Scripps Pier in La Jolla, CA Invited Talk
University of Southern California, Department of Earth Sciences Seminar
2026
Bloom-driven microbial succession shapes methylmercury dynamics in coastal surface waters
Adams, H.M., Hale, R., Bowman, J., Schartup, A.T. · International Society for Microbial Ecology (ISME20), New Zealand
2024
A time series of mercury speciation at Scripps Pier, La Jolla, CA: insights on methylmercury production and cycling in the surface ocean
Adams, H.M., West, J.W., Kübler-Dudgeon, I., Lamborg, C., Bowman, J., Schartup, A.T. · International Conference on Mercury as a Global Pollutant, South Africa
2023
A time-series of mercury speciation at Scripps Pier, La Jolla, CA
Adams, H.M., Kübler-Dudgeon, I., Bowman, J., Lamborg, C., Schartup, A.T. · Gordon Research Conference & Seminar, New Hampshire; Goldschmidt Conference, Lyon, France
2023
Insights from upwelling in the California Current System on mercury biogeochemistry: implications for monomethylmercury supply
Adams, H.M., Cui, X., Lamborg, C., Schartup, A.T. · Goldschmidt Conference, Lyon, France
2022
Mercury speciation in the Southern California Current Ecosystem
Adams, H.M., Cui, X., Lamborg, C., Schartup, A.T. · International Conference on Mercury as a Global Pollutant & Ocean Sciences Meeting (Virtual)
Show earlier presentations (2)
2020
Multi-element dissolved trace metal distributions in surface waters of the Texas-Louisiana Shelf: a synthesis from three cruises 2017–2019 showing the influence of rivers, hurricanes, sediments, and biology
Adams, H.M., Jensen, L.T., Farran, B., Lanning, N.T., Fitzsimmons, J.N. · Ocean Sciences Meeting, San Diego, CA
2019
Natural and toxic heavy metals in sediments from Galveston Bay, Texas following Hurricane Harvey
Adams, H.M., Fitzsimmons, J.N. · Aquatic Sciences Meeting, Puerto Rico

Education, appointments, and skills

Education, appointments, grants, field experience, and technical skills. A full CV is available on request.

Education

2025
Ph.D., Earth Sciences — UC San Diego, Scripps Institution of Oceanography
2022
M.S., Earth Sciences — UC San Diego, Scripps Institution of Oceanography
2019
B.S., Chemistry — University of Southern California
2019
B.A., Environmental Studies — University of Southern California

Selected grants & awards

2025
NSF Postdoctoral Fellowship, OCE-PRF — $341,396
2024
ACS Editors' Choice Award
2023
NSF INTERN Award
2020 & '22
NSF GRFP Honorable Mention
Show full list
2026
ISME Travel Grant
2023
UCSD GPSA Travel Award (Goldschmidt 2023)
2023
Scripps Travel Award (Gordon Research Conference)
2020
Scripps Fellowship, UC San Diego
2019
USC Discovery Scholars Research Award
2017–19
USC undergraduate research & travel fellowships (WiSE, Provost's, conference grants)
2015
USC Presidential Scholarship

Appointments

2025–
Postdoctoral Research Fellow, Scripps Institution of Oceanography — NSF OCE-PRF
2020–25
Graduate Student Researcher, Scripps Institution of Oceanography
2019–20
Assistant Research Scientist, Texas A&M Oceanography
Show full list
2023
Summer Research Apprentice, Ocean Science Analytics, San Diego, CA
2018
Undergraduate Research Scientist, Texas A&M Oceanography — NSF Research Experience for Undergraduates
2017–19
Undergraduate Research Scientist, USC Department of Earth Sciences — Provost's Undergraduate Research Fellowship

Field experience

Seven expeditions since 2017 across the California Current, Gulf of Mexico, Southern Ocean, and Peru — including 36 days aboard R/V Roger Revelle and 27 days aboard BIO Hesperides as part of the Spanish Antarctic Campaign.

Technical Skills

Analytical instrumentation
Gas chromatography–cold vapor atomic fluorescence spectroscopy (Tekran 2500, 2700) Cold vapor atomic fluorescence spectroscopy (Tekran 2600) Atomic absorption spectroscopy (Nippon EMP Gold+, Nippon DMA) Inductively coupled plasma mass spectrometry (Agilent 8900 QQQ, Thermo Element XR) Species-specific isotope dilution Liquid chromatography mass spectrometry Competitive ligand exchange–anodic stripping voltammetry
Sampling & methods
Trace-metal clean samplingMercury speciation analysis Stable isotope tracer incubationsMicrobial culturingDNA/RNA extraction
Data & modeling
Mass budget & flux modelingTime series & regression modeling Machine learning for microbial community analysisMulti-omics integration RMATLAB

Professional memberships

International Society for Microbial Ecology
Association for the Sciences of Limnology and Oceanography

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.

Student Evaluations

4.8/5average rating
100%positive, all metrics
55students enrolled

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!"

Teaching experience

2026
Group Leader & Instructor, Biogeochemistry of the Water Column — The Coastal Ocean Environment Summer School in Nigeria and Ghana (COESSING) (15 students)
2026
Advanced & Foundations of College Teaching Certifications — UC San Diego
2025
Teaching Assistant, SIO3: Life in the Oceans (55 students)
2017–19
Academic Tutor, USC Student-Athlete Academic Services (25 students)

Mentorship

3graduate students
7undergraduates

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.

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)

15students

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.

Working with COESSING participants, Calabar, Nigeria, 2026 Presenting to COESSING participants, Nigeria

Coordinator, 2021–2025

Scripps Community Outreach for Public Education

50+pier tours led
1,000+participants reached

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

100+members

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

2students mentored

Mentored two prospective students from underrepresented backgrounds through the PhD application process. Both went on to pursue graduate education within University of California programs.