Soil ecology is the study of the organisms that live below ground, interacting with plants, each other, and their environment. Bacteria, fungi, protozoa, and nematodes are all microscopic soil organisms that play important roles in decomposition and nutrient cycling. These organisms also are incredibly diverse, and a handful of soil can contain hundreds of different species. The use of molecular, microscopic, and stable isotope techniques allows soil ecologists to study the unseen life in the soil and understand the world beneath our feet. Dr. Treonis currently is studying nematode and microbial ecology in arid ecosystems (the Mojave Desert) and at regional field sites (granite rock outcrops of the Piedmont region).