Jen Schweitzer

UTK ecology and evolutionary biology

"Just take a walk through a forest and it’s easy to see that the soil underneath a pine tree looks different from soil under an oak, but we don’t know very much about how individuals within a species alter their soils," says JDRD team leader Jen Schweitzer.

She and LDRD project team leader Christopher Schadt want to know more about this difference, most especially how plants change the soils and the microbial community feeding off roots and their secretions, or exudates, oozing into the soil and vice versa.

In recent years, many scientists have turned to genetics to expand what they know about living organisms, Schweitzer among them.

For their part, Schweitzer’s team hopes to discover how much control plant genotypes have on the microbial communities responsible for degrading leaf litter and roots, a process which influences carbon (C) storage and nitrogen (N) and phosphorous (P) fertility of the soil.

This project addresses three important questions in microbial and ecosystem ecology, Schweitzer says.

How do varying plant traits, especially those of the roots, affect microbial community structure?

If the microbial communities vary, do ecosystem processes—in this case carbon storage and nitrogen turnover—vary as well?

Do changes in one mineral cycle (carbon) have similar effects in another (nitrogen and phosphorous)?

Schweitzer’s team will test their ideas on specific genotypes of switchgrass, which have a wide range of root architectures and patterns of exudation, to examine the sustainability of switchgrass crops.

JDRD Project: Plant-soil feedbacks impact carbon, nitrogen, and phosphorus cycling: impacts of biofuel crops?;
LDRD Project: Carbon drivers of the microbe-switchgrass rhizosphere interface, Christopher Warren Schadt.

"Genetic based feedback between plants and soil processes is especially important in biofuel species because large areas of cropland are already

being converted to biofuel crops and little is yet understood about their long-term effects on the soil," Schweitzer says.

The project supports two undergraduate students, teaching them the rudiments of ecosystem ecological research. In 2009, Schweitzer and her ORNL colleagues plan to use the data from this research in proposals to the National Science Foundation and Department of Energy.