Janelle Arnold ’23

Headshot of Janelle Arnold

Chemical and Biological Engineering

Project Title

Investigating Trace-Gas Uptake in Chilean High Andes Soil Microbe Communities

Presentation Link

View Janelle's Presentation

Certificate(s): Environmental Studies

I analyzed metagenomic data recovered from soil samples collected from a hot spring in Chile’s Atacama Desert. The microbial communities in this region are unique in that they survive under extreme conditions and with few nutrients. My goal was to investigate the biodiversity of these microbial soil communities and to identify high-affinity trace-gas oxidizers. Previously, the Onstott Lab identified from these soil samples hydrogen and carbon monoxide gas uptake that appeared to be biological and more active in areas farther from the hot spring. I investigated the uptake of hydrogen by using the group 1h hydrogenase enzyme in nickel-iron alloy as a biomarker to identify organisms with hydrogen-scavenging metabolisms. Using Hidden Markov models, I was able to train a program to identify these hydrogenases within genome sequences. Similar to the previous data, I identified more high-affinity hydrogen oxidizers farther from the hot spring. This supports the idea that microbial communities in low-nutrient environments are more likely to rely on trace-gas scavenging for their survival. This internship gave me more insight into the field of geobiololgy and bioinformatics, while equipping me with the knowledge to analyze more genomic data in the future.

Internship Year


Project Category

Climate and Environmental Science


Geomicrobiology Group, Department of Geosciences, Princeton University


Tullis Onstott, Professor of Geosciences; Zachary Garvin, Ph.D. candidate, Geosciences