College of Agriculture & Natural Resources
Environmental Science & Technology

Microbial Ecology and Biogeochemistry Lab

The Microbial Ecology and Biogeochemistry Lab at UMD is dedicated to understanding how microbial community composition impacts biogeochemical processing and influences the resilience and resistance ecosystem functions. We apply molecular methods such as sequencing of DNA and RNA to examine microbial communities, and then pair those observations with measures of activity such as enzyme assays, stable isotope tracing, and in situ response. We apply these methods and ask questions in a number of ecosystems, including: agricultural soils, wetlands, and urban soils. We hope to shed light on the role of microbes in mediating key natural process and share our love of microbes with students at all levels of education and the general public.

Left to Right: Christine Marietta, Zachary Bernstein, Amr Keshta, Josh Gaimaro, Zachary Berry, Brian Aiken, Lindsay Wood, Dietrich Epp Schmidt, Gianna Robey, Martina Gonzalez Mateu, Dr. Andrew Baldwin, Eni Baballari, Dr. Chih Han Chang, Amy Kuritzky, and Dr. Stephanie Yarwood


Chih-Han Chang

I am a postdoctoral researcher working with Stephanie Yarwood from UMD and Katalin Szlavecz from JHU on using environmental DNA from NEON soil samples to understand the factors driving earthworm species richness at the regional and continental scales. Soil ecology emerged as one of my main research foci while I enjoyed years of studying the diversity, molecular phylogeny, and biogeography of earthworms. I earned my PhD from the Johns Hopkins University, focusing on interspecific competition among invasive earthworms, and the effects of these interactions on soil microbial communities and soil C dynamics. Currently, I am interested in understanding soil invertebrate biodiversity at different scales, the complex interactions of belowground and aboveground communities, and the effects of these interactions on ecosystem functions. In addition to the NEON soil eDNA project, I am also considerably involved in several projects focusing on the complex effects of land use history and earthworm community structures on soil stable isotope signatures, microbial communities, and C biogeochemistry. 

Graduate Students 

Christine Prasse 
I am a pre-doctoral candidate in Environmental Science and Technology’s Wetland Science Program, advised by Drs. Stephanie Yarwood and Andrew Baldwin. Wetland microbial ecology became my main focus of study as an undergraduate. I received my M.S. in 2010, researching microbial ecology in freshwater non-tidal wetlands. As a pre-doctoral candidate, I am refining my understanding of soil development and biogeochemistry in hopes of gaining insight into the complexity of microbiology and wetland function. I am specifically interested in the effects of wetland restoration on microbial community development and biogeochemical function, specifically microbial-mediated carbon and nitrogen cycles.  Currently I am exploring microbial community compositional and functional (i.e., nitrification, denitrification, methanogenesis, etc.) differences between restored and natural wetlands in urban and suburban setting. Additionally, I am exploring how restoration techniques, such as amendments of organic matter to sediments, affect wetland microbial-mediated function.

Dietrich Epp Schmidt

I was born in Boston, MA; however, I have lived in Maryland for the better part of forever. It is my home (yay Terps!). For a long time, I have been fascinated by the ways in which human behavior (including culture and economy) interact with the environment to eventually control ecosystem processes and outcomes. I became interested soils in particular by way of sustainable agriculture, and the long history of collapsed empires that are associated with various failures to properly manage or conserve soil resources. Through my exploration, I became convinced that human civilization is as much a feature of the ecological landscape as the oceans or forests; as such we must study our own behavior as a natural entity. Thus, for my MS, I jumped at the opportunity to join the Global Urban Soil Ecology Education Network, and evaluate the urban convergence hypothesis with respect to the effect of urbanization on microbial communities. I am looking forward to continuing at the University of Maryland for my PhD, and joining the Plant Health Project to evaluate the effects of Glyphosate on soil ecosystems.

Martina Gonzalez Mateu

My interest in soil microbiology started as an undergraduate at the University of Buenos Aires. In 2013 I came to Maryland as an exchange student and got an opportunity to work with Dr. Yarwood and learn about wetland microbial ecology. As a result of that experience I decided to come back to UMD to pursue a Ph.D. in the Environmental Science Department. My research interests are very broad but I’m mostly interested in different aspects of ecology and conservation biology. I’m currently focusing on wetland plant and microbial ecology, and the first part of my research is looking at the interactions between native and invasive lineages of Phragmites australis under different carbon and nitrogen conditions. And for the next part of my research, I would like to understand more about root endophytes associated with wetland plants and particularly fungal mutualists in Phragmites. 

Eni Baballari

While finishing my undergraduate degree at University of Maryland, I got the opportunity to work with Dr. Stephanie Yarwood and the members of her lab group as a research assistant. Being part of the very energetic Yarwood lab made me even more excited about continuing my education in Environmental Science. I will soon graduate from UMD with a bachelor’s degree in Environmental Science with a soil Soil and Watershed Science concentration, and I am proud to say that I will stay on at Maryland as a Graduate Research Assistant for Dr. Yarwood. I will be studying the benefits of Class A biosolids (produced from the DC wastewater treatment plant) in soil and plants when applied to land.

Lab Technicians

Zachary Berry

I have been working with Dr. Baldwin and Dr. Yarwood’s graduate students for approximately one year. I am particularly interested in wetlands and wetland plants for their restoration and water quality potential, as well as their possible remediation applications. I have been deciding on whether or not to look for work in the private sector doing field work in wetland delineation, or to pursue a graduate degree researching algae, another interest of mine. I am happy to be able to work with Dr. Baldwin and Dr. Yarwood and their graduate students, and thank them for the opportunity. It has been and continues to be a blast!

Josh Giamaro

I graduated from University of Maryland, College Park in 2015 with a B.S. in Environmental Science and Technology as well as a minor in Geographic Information Systems. Backpacking, hiking, species identification and cultivation are a few of my hobbies that lead me to where I am today. I developed an interest in the inherent patterns and connectivity of everything in the natural world. Early in college I started working in wetlands for a non-profit organization, South River Federation (SRF) where I conducted Amphibian Habitat Monitoring Studies in restored and unrestored wetlands to determine their species richness, created maps using geographic information systems, and designed, planted, and maintained storm water retrofit projects. In addition to working at SRF I worked at MOM’s Organic Market while going to school full-time. Shortly after I started working in Dr. Yarwoods lab cultivating dark septate endophytes with Martina, at the USDA-BARC preforming data analysis and operating their Pyrolysis GS-MS with Jeff Buyer and Christine, and in Dr. Baldwin’s lab studying shifts in carbon from many different habitats up to 50cm in depth with Amr Keshta.


Lindsey Wood

I am currently working towards my undergraduate degree in Microbiology at the University of Maryland. I am from the Eastern Shore of Maryland and grew up sailing on the Chesapeake Bay, which sparked my interest in the conservation of the Bay. I became interested in microbiology when learning about bioremediation in an organismal biology class and became intrigued by the roles of bacteria and other microbes in our world. In Dr. Yarwood’s lab, I am assisting on a project that aims to quantify the denitrification activity in restored wetlands on the Eastern Shore.

Zachary Bernstein

I am an undergraduate student here at the University of Maryland. I am majoring in Environmental Science and Policy, with a concentration in Biodiversity and Conservation Biology. I grew up in Chicago, but came to Maryland to experience the east coast for a few years. My work mainly focuses on nutrient storage in wetlands, and comparing nutrient storage in natural versus restored wetlands.  

Jessica King 

I am a freshman in the Environmental Science and Technology Program at the University of Maryland. I plan on pursuing some aspect of the environment throughout my college career, but I am unsure exactly what interests me the most. Everything about the environment interests me! Currently, I am working in the laboratories of Dr. Baldwin and Dr. Yarwood, and I hope to learn copiously from this experience. 

High School Interns
  • Gianna Robey
Lab Alumni
  • Glade Dlott—Glade received his master’s degree in 2015 and is currently a PhD student at Standford University
  • Holly Bowen—Holly received her master’s degree in 2016 and is currently employed by Cornell University Extension
  • Tamara Walsky—Tammy graduated from UMD in 2015 with her BS and is currently employed by John’s Hopkins University
  • Ashely Robey—Ashely completed a high school internship and is now an undergraduate at Anne Arundel Community College
  • Sara Elbeheiry—Sara received her BS and is now employed by USDA
  • Steph Jamis—Steph earned her BS and is a graduate student at Florida State University 
  • Matthew Klein—Matt earned his BS and is a graduate student at Oregon State University 
  • Gaelle Njonkou—Gaelle earned her BS and is a student in John’s Hopkins School of Pharmacy
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