Submitted by Mary K. FIRESTONE on
Bacteria and fungi are the two most dominant groups of microorganisms that drive many essential biogeochemical cycles on the planet. However, mechanistic understanding of the interactions among them, and the outcomes of these interactions in the context of soil nutrient cycling are far from clear. Our broader goal is to contribute to the fundamental understanding of the ubiquitous interactions between bacterial and fungal communities in soil, and how bacterial-fungal interactions (BFI) determine the availability and fate of carbon across complex soil niches (rhizosphere, detritusphere, hyphosphere).
To track BFIs and their roles in soil carbon cycling in California’s Mediterranean annual grassland, we have set up a field experiment at HREC, Hopland, CA to study how the availability of different C sources (including rhizodeposits, or carbon leaked out from plant roots; hyphodeposits, carbon leaked out from fungal hyphae; and root litter) alters BFIs under both ambient precipitation and drought conditions.
We will conduct several field labeling events in the spring of 2024. Plants in the field experimental plots will be supplied with 13CO2 for durations of days to incorporate 13C into their biomass and root exudates, which are the primary C source to support belowground food web. We will then sample and study the bacterial and fungal communities that are enriched in 13C and actively participated in the consumption, transport, and modification of plant-derived carbon.
The field labeling needs well-designed and built infrastructure to be successful. These include solar power system, gas lines, electric lines, and labeling chambers. During the Fall 2023 semester, we will be doing all kinds of prep work to build these pieces for the coming spring. The student may be offered to stay on this project and help with spring 2024 labeling and sampling upon agreement between the student and supervisor.
Help with building the infrastructure for the field labeling. Actual work may include wiring and setting up electric and gas lines, drilling/tapping holes on plastic materials and other common hardware work.
The student will be trained on tasks so no prior experience is required.
The student is welcome to involve in other relevant roles (soil coring, gas flux measurement, etc.) in the project if interested in learning.
Responsible and able to follow safety procedures.
Willing to perform hands-on hardware work.
Since part of the work will be conducted at our field site in Hopland, CA, schedule with a full day open for working on this project is highly preferred.