Graduate student Glade Dlott receives award to study soil microbes at national lab

Glade Dlott
Glade Dlott (Photo by Laura Bogar)

In only a handful of soil, you hold thousands – or even tens of thousands – of different kinds of bacteria and fungi. These microbes break down waste, help nutrients cycle through ecosystems and serve as food sources for other microscopic soil dwellers, like protists, mites and nematodes.

Although we are certain that microbes in soil play these important roles, we don’t have many details about how, why, when and to what extent they perform their various functions. Wanting to know more, GLADE DLOTT, a graduate student in the Peay lab, is taking a closer look at soil microbe behavior and interactions. In support of this research, he has received a 2018 Office of Science Graduate Student Research award from the U.S. Department of Energy (DOE).

“Despite being the engine that drives soil fertility and supports terrestrial life, we know very little about soil microbes’ individual micro-habitats and ecological niches,” said Dlott, who is advised by KABIR PEAY, assistant professor of biology. “I really believe that this study might change the way both soil scientists and ecologists think about soil fungi and bacteria.”

Specifically, Dlott has gathered stream sediments from Stanford’s Jasper Ridge Biological Preserve to investigate the “fungal highway.” This is a water film that surrounds the web-like bodies of fungi, which previous lab studies have suggested as the main route by which bacteria move through soil. But this hasn’t been closely studied in soils taken from nature, which are more complex than their lab-based counterparts.

“Our study asks: how important is this ‘fungal highway’ in the lives and fitness of soil bacteria, and what soil conditions – physical structure, nutrient heterogeneity – make it more or less important?” Dlott said.

Through the DOE grant, Dlott will pack up his Jasper Ridge fungi and bacteria and head to the Pacific Northwest National Laboratory (PNNL) to continue his research with Kirsten Hofmockel, an expert in microscale spatial studies of soil microbes. Individual soil bacteria are around 1 to 2 micrometers in size and the advanced technologies at the lab will enable the researchers to see these organisms up close. They will introduce Dlott’s microbes into soil samples and observe how they are affected by different experimental conditions, such as changes in moisture and nutrient availability.

The intended final product of this research is a quantitative explanation of the importance of the fungal highway to soil bacteria and a better understanding of how physical and chemical factors control microbial interactions in soils. With a more precise concept of the relationship between large-scale processes and microbe functioning on the micro-scale, findings from this research could improve our ability to predict rates of nutrient cycling under different conditions – including those that may come to pass as a result of climate change.