A Camera That Sees in the Soil

(Photo – Oumeng Zhang / Biorender)

Beneath grasses, trees, flowers, and moss, just below our feet, there lies a complex ecosystem called the rhizosphere.

By Katie Neith

Composed of the soil, fungi, nutrients, and more that surround plant roots, this layer plays an essential role in the well-being of the planet and the growth of the crops needed to feed its inhabitants.

“The health of the soil underpins the survival of the overall terrestrial biosphere,” says Changhuei Yang, Caltech’s Thomas G. Myers Professor of Electrical Engineering, Bioengineering, and Medical Engineering and a Heritage Medical Research Institute Investigator.

Studies of the rhizosphere rely on soil and root samples taken from the ground, which upsets environmental conditions and gives an incomplete picture of the dynamics at play. Instead of digging up the dirt, Yang and members of his lab plan to build a camera they can bury in the soil to monitor the rhizosphere in its natural state. They plan to use this imaging system to capture interactions between organisms, root systems, and networks of fungi.

The project was inspired by a conversation between Yang and Dianne Newman, the Gordon M. Binder/Amgen Professor of Biology and Geobiology.  Newman and members of her lab are working on ways to monitor changes in phosphorus—a fundamental nutrient for all living things—in soil. Their goal is to develop specific bacteria that can improve the absorption of phosphorus in crops.

Zhang, whose biophotonics lab has mostly focused on building cameras for medical imaging, has begun collaborating with her group and bringing his optical expertise to bear.  “I am building a fluorescence scanning system to identify the different kinds of proteins that bacteria express when they need more phosphorus,” he says. “I’m trying to use optical methods to detect these very subtle changes.”

Cameras and microscopes typically operate on tables that are extremely stable, allowing for proper alignment. Building an optical system that can operate underground must deal with wiggling creatures, and soil that is easily moved around by rain, wind, and earthquakes. Fortunately, the team can use computational methods to transform a fuzzy picture into a clearer one.

Yang notes, “Since we can expect forest fires to occur more frequently and with greater intensity in California, it is important we study forest rhizospheric systems and better understand what we can do to make them more resilient and able to bounce back more quickly after a fire.”

Read the full article at Caltech News.