# People ![Hoffman steps](/sites/g/files/omnuum8991/files/johnstonlab/files/052318_eps_0060_0.jpg) ## Faculty [### David Johnston ](/people/david-johnston) Professor of Earth and Planetary Sciences & Co-Director of Graduate Studies He/Him/His Primary research interests: Isotope geochemistry and historical geobiology; re-animating ancient ecosystems and ocean chemistry using stable isotope systems, chemical speciation techniques, modern microbial experiments (for calibration) and... ![David Johnston](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/2025-08/Johnston_Dave_02-scaled-1-aspect-ratio-1-1-300x300.jpg?itok=GFSqkJqm) ## Staff [### Corinne Engber ](/people/corinne-engber) Research Group Administrator She/Her/Hers ![Corinne Engber](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/2025-08/Headshot_cengber.jpg?itok=mBY-x-wC) [### Julien Foriel ](/people/julien-foriel) [julien\_foriel@fas.harvard.edu](mailto:julien_foriel@fas.harvard.edu)Research Scientist He/Him/His I am an isotope geochemist, and like all isotope geochemists, I like to build and tinker with instruments, develop new analytical methods and new isotopic tools to understand elemental cycles on Earth. I am particularly interested in the... ![Julien Foriel](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/2025-08/Foriel_Julien_02-scaled-1-aspect-ratio-1-1-300x300.jpg?itok=kxKT27dh) ## Associated Researchers [### Daniel Crocker ](/people/esther-kennedy) Postdoctoral Fellow He/Him/His Dan is a stable isotope geochemist interested in the sources, transformations, and environmental cycling of organic matter in a variety of geochemical environments—from ancient meteorites to the modern Earth. He completed his Ph. D. at the... ![Daniel Crocker](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/2025-08/Crocker_Daniel_01-scaled-aspect-ratio-1-1-300x300.jpg?itok=Ndt5XgUJ) ## Graduate Students [### Amanda Calhoun ](/people/cerys-holstege) Ph.D Student She/Her/Hers Amanda received her B.A. in Chemistry and Earth Sciences from Dartmouth College in 2023. Her research has focused on understanding the relationship between archaeal lipid production and geochemical conditions in hydrothermal springs. At... ![acalhoun](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/acalhoun_1.jpg?itok=BIrjpehQ) [### Charlotte Minsky ](/people/charlotte-minsky) Graduate Student Charlotte is a graduate student in the Wordsworth Group. person ## Visiting Faculty [### Eve-Lyn Hinckley ](/people/eve-lyn-hinckley) Visiting Professor Eve-Lyn Hinckley’s research focuses on studying the elements that underlie all life on Earth, with an emphasis on how they are changed by human activities and how those changes feed back to affect human welfare. Dr. Hinckley earned her Ph.D. in Geological... ![A photo of Eve-Lyn Hinckley](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/2025-10/Eve_Hinckley2.JPG?itok=SwVmH3Oj) [### Mark Thiemens ](/people/mark-thiemens) Visiting Professor Thiemens' research involves mass independent isotope effects and their application to solar system origin, origin and evolution of life of earth, cosmochemistry (lunar, meteorites and Mars), climate change and measurements of oxygen and sulfur isotopes... person ## Visiting Scholars [### Peter Crockford ](/people/peter-crockford) Post-doctoral Fellow person [### Claire Hayhow ](/people/claire-hayhow) Visiting Scholar person [### Kevin Sutherland ](/people/kevin-sutherland) Post-doctoral Fellow person [### Anna Waldeck ](/people/anna-waldeck) Former Graduate Student Now a Post-Doctoral Fellow at Northwestern University She/Her/Hers Anna completed a BSc in Chemistry and in Geophysical Sciences at the University of Chicago in 2014. Since 2013 she has worked in a stable isotope ratio laboratory there, measuring oxygen isotope ratios in phosphates contained in small shelly... ![microscope.jpg.jpeg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/microscope.jpg.jpeg?itok=Q6Df-V7d) Open all sections Close all sections ### Gone, but not forgotten expand\_more ## Gone, But Not Forgotten... [### Alex Bradley ](/people/alex-bradley)Former Postdoctoral Fellow Now on the faculty at Washington University at St Louis. ![alex.jpg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/alex.jpg?itok=IRcTqwBc) [### Alex Morgan ](/people/alex-morgan)Former Thesis Student Alex is now at Cambridge University working on her master's degree. ![alex_morgan.jpg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/alex_morgan.jpg?itok=GXUarwRT) [### Alyssa Chan ](/people/alyssa-chan) Former Undergraduate Thesis Student Alyssa is a senior concentrating in Chemistry and Earth and Planetary Sciences, with a secondary field in the Comparative Study of Religion. She joined the Johnston group in Summer 2014. Her thesis research involves evaluation of organic molecules as... ![img_1391.jpeg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/img_1391.jpeg?itok=DaAlZyW0) [### Ana Gonzalez Valdes ](/people/ana-gonzalez-valdes) 5th Year Ph.D Student Ana Gonzalez Valdes received her B.A. in Earth Sciences from Columbia University in 2016. At Columbia and Caltech she worked to understand how microbes in unique environments cycle nutrients like phosphorus and sulfur. At Harvard Ana will be spanning the... ![gonzalezvaldesphoto.jpg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/gonzalezvaldesphoto.jpg.jpeg?itok=GJPAr5yi) [### Andy Masterson ](/people/andy-masterson) Former Ph.D student now works at the Northwestern University IRMS Lab ![img_0820.jpeg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/img_0820.jpeg?itok=-NEMca-M) [### Beck Saine ](/people/beck-saine) Former Undergraduate Research Assistant he/him/his or they/them/theirsBeck is a rising junior at Harvard College pursuing a joint concentration in Chemistry and EPS. He is starting as a research assistant in the Johnston Group in summer 2020 with plans to explore multiple topics within the... ![Beck Saine](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/screen_shot_2020-04-17_at_11.15.34_am.png?itok=y1fkHdTx) [### Ben Cowie ](/people/ben-cowie)Former Post-doctoral Fellow Ben is an isotope geochemist with diverse interests in the Earth sciences. In the Johnston Group, he is currently exploring questions surrounding the evolution of the atmosphere and biosphere over the most recent billion years of Earth history using a... ![ben_nose_hill.jpeg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/ben_nose_hill.jpeg?itok=UJ_d7YPy) [### Ben Gill ](/people/ben-gill)Former Post-doctoral Fellow Now on the faculty at Virginia Tech. ![gill_image.jpg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/gill_image.jpg?itok=RrAdpnc1) [### Cecilia Sanders ](/people/cecilia-sanders)Former Undergraduate Student person [### Chloe-Rose Colombero ](/people/chloe-rose-colombero) Former Undergraduate Research Assistant Chloé-Rose is a senior at Harvard College concentrating in Organismic and Evolutionary Biology with a secondary field in Earth and Planetary Sciences, focusing on marine sciences. She joined the Johnston group in the summer of 2020 to work on a... ![Chloe-Rose](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/screen_shot_2020-04-17_at_11.00.46_am.png?itok=vyMiuSth) [### Daianne Höfig ](/people/daianne-h%C3%B6fig) 1st Year Ph.D Student She/Her/Hers My name is Daianne, and I am originally from Brazil, where I obtained a BSc in Geology and an MSc in Geochemistry. During my studies at Texas A&M University, I transitioned from U-Pb zircon geochronology to organic geochemistry. Isotopes are... ![Daianne](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/daianne.jpg?itok=j-awbiTW) [### Ella Hughes ](/people/ella-hughes)3rd Year Ph.D. Student Ella is coming to Harvard from the UK, where she completed a BA degree in Natural Sciences and MSc degree in Earth Science at the University of Cambridge. Her Master’s research at Cambridge and Caltech focussed on the sulfur isotope composition of organic... ![Ella](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/ella_photo.jpeg?itok=h6jXiUjV) [### Emma Bertran ](/people/emma-bertran) Former gardute student The intimate interaction between microbial life and earth leaves specific chemical signatures that record information on microbial activity, and paleo-environmental conditions. As a geobiologist, my goal is to interpret these signatures and reconstruct an... ![Emma_photo](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/dsc_0086_1.jpg?itok=rWbxNui8) [### Erik Sperling ](/people/erik-sperling)Former NASA Postdoctoral Fellow Now on the faculty at Stanford University ![sperling_mollusc.jpg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/sperling_mollusc.jpg?itok=4TLMdPO8) [### Erin Beirne ](/people/erin-beirne)Former Johnston Lab Manager Now a Research Associate in marine environmental chemistry at Bigelow Laboratory for Ocean Sciences ![erin.jpg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/erin.jpg?itok=FMC8R4aR) [### Frasier Liljestrand ](/people/frasier-liljestrand) Former Graduate Student Frasier got his BS in Earth Science from Rice University in 2013. While he was at Rice, he did research in biogeochemistry focusing broadly on trying to quantify global carbon fluxes and budgets. Here in the Johnston group Frasier hopes to expand his... ![img_0216.jpeg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/img_0216.jpeg?itok=kaa240th) [### Haley Olson ](/people/haley-olson) 3rd Year Ph.D. Student She/Her/Hers Haley received a BA in Geology from Carleton College in 2017. Haley's research uses stable isotope geochemistry to constrain marine geochemical conditions throughout geologic time (thus far from the Archean to the Neogene). She is currently... ![Haley](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/haley.png?itok=IPJQ2gGF) [### Jordan Hemingway ](/people/jordan-hemingway) Assistant Professor/ETH Zurich He/Him/His I'm interested in connections between the geologic and biospheric carbon cycles. Specifically, my work aims to understand how processes occurring in river basins transfer carbon between these two cycles in order to regulate atmospheric CO2... ![Jordan Hemingway](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/jdh.jpg?itok=oGpQYLFE) [### Joseph Shaffer ](/people/joseph-shaffer)Former Undergraduate Thesis Student Joe was an undergraduate concentrating in earth and planetary science with a secondary in chemistry. His thesis is a paleoenvironment study of the Utica focusing on whether the geochemical trends observed are globally or locally forced and what that means... ![shaffer.jpeg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/shaffer.jpeg?itok=GXyKTnlq) [### Kalina Grabb ](/people/kalina-grabb) Undergraduate Thesis Student Karina was an undergraduate joint concentrator in Earth and Planetary Science and Environmental Engineering who has been working with the Johnston Group since her sophomore year. Her interests in biogeochemistry carries across sulfur, oxygen, and nitrogen... ![kalinagrabb.jpg](/sites/g/files/omnuum8991/files/styles/hwp_4_5__690x865/public/johnstonlab/files/kalinagrabb.jpg?itok=c_wp7eIs) ## Associated Research Groups - [The Wordsworth Group](https://eps.harvard.edu/research-group/wordsworth-group/) - [The Pearson Group](http://pearson.eps.harvard.edu/home) - [The Drabon Group](https://eps.harvard.edu/research-group/drabon-group/) - [The Sunderland Group](https://eps.harvard.edu/research-group/sunderland-group/) - [The Uno Group](https://eps.harvard.edu/research-group/uno-group/)