From Whales to Microbiology

“There are more microbes in a gram of soil than there are stars in the sky,” says Dr. Yarwood.

May 30, 2013

Growing up in Oregon, Dr. Stephanie Yarwood dreamed of studying whales. Currently, an assistant professor of environmental microbiology in the Department of Environmental Science and Technology (ENST), she still has not forgotten about whales, but when asked about her shift of interest, she replies: “microbes are way more powerful!”


This is Dr. Yarwood’s first year of teaching environmental microbiology at the University of Maryland, but her hands are already full with various microbial projects. Microorganisms carry out many important functions of our lives. They fix nitrogen needed for plant growth, they weather minerals during soil formation, and they are important tools in green technologies like biofuels. Her research focuses on soil microbial communities, exploring how the presence or absence of some microorganisms affects the functioning of ecosystems and soil development. “There are more microbes in a gram of soil than there are stars in the sky,” says Dr. Yarwood. Even though we realize their importance, we know very little about them. “Only one percent of microbes can be grown in the lab,” notes Dr. Yarwood. “New tools are allowing scientists to study these organisms in ways we didn’t think were possible 20 years ago.” Today more than ever, microbial ecologists rely on molecules like DNA to give us clues about the identity and function of microbes under scrutiny.


Dr. Yarwood especially enjoys the interdisciplinary opportunities within ENST. “In order to understand how soil microbes play a role in soil formation, we need to understand the physical, chemical, and biological relationships.” She is currently collaborating with Oregon State University to test the ability of microbial communities to maintain important functions, such as the decomposition of plant material after disturbance and learning how microorganisms colonize subsurface soil horizons. She also started a project with scientists at the ARS Sustainable Agricultural Systems Lab to study how changes in agricultural management might affect microbes and the processes they carry out. Moreover, she is investigating how microbial populations and soil nutrient cycling recovers during land reclamation of surface mining sites, in collaboration with Virginia Tech. “I really like to collaborate across scientific disciplines, to answer questions that I couldn’t answer by only studying microbiology,” Dr. Yarwood concludes.