How Microbes Feed the Soil: Tracing Carbon from Dead Microbial Biomass

Soils are living superorganisms that harbor the planet’s largest and most diverse microbial communities. These microbes drive the transformation and turnover of organic matter, regulating the balance between carbon storage and release. A major component of soil organic matter (SOM) is microbial necromass, the remains of dead cells, whose consumption and recycling by microbes provide a source of carbon and nutrients. Necromass is increasingly recognized as one of the most persistent components of SOM, contributing to soil structure, fertility, and overall soil health. However, it is not yet clear how the structure of microbial food webs might influence necromass susceptibility to degradation, and, in turn, its contribution to long-term carbon and nutrient storage.

This project aims to explore which soil microbes use necromass as a resource and how it is metabolized by different microbial groups. By tracking the movement of carbon from 13C-labeled necromass into active microbes, we can identify which microbial groups are most involved in its transformation and the metabolic pathways they employ. To achieve this, we will combine metagenomics with stable isotope probing metaproteomics, linking active microbial taxa with their metabolic functions.

The student's role will be to assist with laboratory experiments, including soil microbial DNA extraction, DNA quality and quantification analyses, and sequencing library preparation. The student will also contribute to data organization, preliminary bioinformatics analyses, and literature analysis related to microbial ecophysiology and soil carbon cycling.

Essay prompt

Why are you interested in participating in this opportunity, and how do you see it contributing to your academic or professional goals?