PhD Studies

Every relationship between a mentor and mentee is unique and meaningful. Here, Professor Jan Amend and his PhD student Heidi Aronson share thoughts about their experiences.

Jan Amend, Professor of Earth Sciences and Biological Sciences:

As a graduate student and postdoc, I was mentored by several extraordinary scientists. All of them helped me grow as a scientist, and I’m sure that I subconsciously picked up mentoring skills along the way. My PhD advisor’s mentoring style worked for me as a student, but I could not and would not want to adopt it as my approach to working with students. The same applies to my post-doc advisors.

Heidi Aronson, PhD Candidate in Marine Biology and Biological Oceanography:

We knew that the search for sulfur comproportionators would be a high-risk, high-reward project, but Jan encouraged me to take on the challenge. Jan gave me the independence to pursue my thesis project in whichever directions I was interested. Although his somewhat “hands-off” approach was initially daunting, it allowed me to really take ownership of my work and ensure that I had accounted for all of the risks and potential outcomes with each step of the project.

Jan Amend:

Heidi’s project, at least half of it, started 20 years before she ever came to USC, when I was doing field work on Vulcano, Aeolian Islands, Italy. A new nitrogen metabolism, later termed anammox, had been proposed and then verified to be carried out by microorganisms. In anammox, microbes combine oxidized and reduced forms of N to produce an intermediate form – the chemical term for this type of reaction is comproportionation. I thought that if this could happen with nitrogen, why not with sulfur? On Vulcano, you can smell the sulfide (reduced form of S) and since it is a marine environment, there is plenty of sulfate around (oxidized form of S); there are also precipitates of elemental sulfur (the intermediate form). I thought there was a project in this somewhere, proposing a new metabolism and then hunting for the organisms that could live off this predicted new energy source.

I pitched this idea to Heidi and she ran with it. The germ of the idea was mine, but this absolutely became Heidi’s project.

Heidi Aronson:

Because this was an interdisciplinary project that would involve thermodynamic calculations, field research, geochemistry, microbial cultivation, isotopic analyses, and analytical chemistry, it was necessary for me to build a network of collaborators and mentors. Jan encouraged me to include collaborators from Penn State, New Mexico Tech, Stanford University, Caltech, the French National Centre for Scientific Research and USC. Each of my collaborators brought something different to the table and was crucial to the success of my thesis project.

We ultimately decided to being our search in sulfidic caves at Frasassi, Italy, in collaboration with Dr. Jenn Macalady at Penn State University. After a successful field expedition at Frasassi, I made Jenn my co-advisor for my thesis. Jenn provided a different style of mentorship – because Frasassi has been her research site for almost two decades, she was able to engage in detailed conversations about sample sites, sample collection techniques, lab analyses, and specific microbes that are known to inhabit the caves. While still providing me with direction and advice, Jenn gave me the freedom to decide which analyses to perform and which steps to take next.

Jan Amend:

Because grad school can be frustrating and challenging and lonely, it is important in my view that the students LOVE their projects. When things don’t go well, the love for the project will get them over the hurdles – and there are many. That’s why I don’t assign projects; the student has to feel real ownership of the project. I certainly suggest ideas and iterate with a student on project development, but it is the student’s project – they will be first author on publications!

Heidi Aronson:

The freedom that Jan gave me in my research allowed me to be creative and explore several different projects. I gained lots of experience writing grant proposals and personally raised over $200,000 to fund most of my PhD research. This independence was crucial to my development as a scientist and later informed how I approached mentoring my own students. I aimed to give my mentees a sense of ownership of their research and allowed them to pursue the questions that interested them, while still guiding them through any that they encountered.