Dan Johnson, PhD

About Me

I am a geochemist currently beginning work as a Postdoctoral Research Associate in the lab of Mark Torres at Rice University. My PhD thesis at Caltech was advised by Jess Adkins and completed in October 2020. In my thesis research, I focused on the using sulfur isotopes to understand processes in the modern and ancient marine sulfur cycle. More broadly, I am interested in reconstructing past Earth surface processes and chemical fluxes using the geochemical study of sedimentary materials. Our understanding of how these processes have operated in the past informs our predictions of how the processes may respond to future changes to the Earth system (especially anthropogenic global warming).


I am driven by a desire to understand how Earth's surface processes have varied through time and, in turn, how variations in these processes have affected life and climate. To do this, I use the geochemical analysis of sedimentary materials combined with mathematical modeling. This combination of measurements and modeling help me answer two basic questions about any period in Earth's past: "What happened?" and "How did it happen?". My PhD thesis focused on these questions in the context of sulfur isotopes in sedimentary materials. As of November 2020, I will be switching gears to study the controls on nutrient input and organic matter preservation in natural sediments.

Read more about my past and present research here.


My first journal article was recently (Sept. 2020) published in the journal Earth & Planetary Science Letters and can be found here. My PhD thesis will also be available to the public soon. 

Curriculum Vitae

You can learn more about my professional background by downloading my Curriculum Vitae (last updated October 5th, 2020).


I am passionate about increasing diversity and inclusion, mental health awareness, and public outreach within the geosciences. I also enjoy learning about and implementing new pedagogical strategies shown to increase educational equity and effectively engage students in the classroom. You can learn more about some of the work I've done and cool resources I've come across here.

Fun Stuff

I have many hobbies outside of my research work. I enjoy playing music, long distance running, camping, hiking, and reading literature. See this page for some fun photos and more.

Contact Me

Due to the ongoing COVID-19 pandemic, I am most accessible by email and social media. Please see the footer banner for links to my email, my LinkedIn page, and my Twitter page. Looking forward to hearing from you!