Lectureship in Soil and Environmental Sciences


(JUNE 7, 2024 | Tower at STAR, Audion)


On June 7, 2024, we celebrated the career and legacy of Donald L. Sparks, Ph.D. Alumni, faculty, staff, students, and friends all gathered to honor the career of an incredible colleague, teacher, mentor, scientist, advisor and friend. Professor Sparks served as the Unidel S. Hallock du Pont Chair; Francis Alison Professor; professor of Plant and Soil Sciences, Chemistry and Biochemistry, and Civil and Environmental Engineering; and founding director of the Delaware Environmental Institute.

Speaker bios

Scott Fendorf is a soil scientist and biogeochemist who examines the chemical and biological processes involving contaminant and nutrient cycling. The outcomes of his studies inform groundwater contamination threats, food safety, and the role of soils in global carbon cycling and mitigating climate change. A highlight of his work on the fundamental biogeochemistry of arsenic coupled with field work from Bangladesh, Cambodia, and Vietnam to the Central Valley of California has led to an understanding of how arsenic and other contaminants enters groundwater, a process that is impacting aquifers across the globe. He has helped lead a bridging of groups focused on solving what is termed ‘the largest mass poisoning in history’. Most recently, Scott’s research is unearthing the unforeseen health risk of naturally occurring toxic metals in wildfire smoke and dust.  

Scott is the Huffington Family Professor in, and the founding chair of, the Earth System Science Department.  He is also a Senior Fellow in the Woods Institute for the Environment. Since the inception of the Doerr School of Sustainability (in September 2022), he has served as the Senior Associate Dean for Integrative Initiatives.  

Brian Farkas began his role as Dean of the University of Delaware College of Agriculture and Natural Resources in Spring 2024. A renowned food scientist, process engineer, teacher and researcher, Farkas brings to UD nearly three decades of professional experience across academic and corporate sectors. Most recently, and since March 2020, he served as chief science officer in McCormick & Company’s leadership team, leading the company’s global research and development organization, directing strategy and execution, and contributing to product and packaging development. Prior to McCormick, he was department head and professor for nearly seven years at Purdue University’s Department of Food Science. His responsibilities as head included setting the vision and direction for the department and managing operations for its programs. Farkas studied engineering at the University of California, Davis, where he obtained a Ph.D. and master’s degree. He received a bachelor’s of science degree in food science from the University of Delaware, minoring in microbiology. Upon completing his doctoral studies, Farkas moved to North Carolina State University. There for nearly 19 years, he served as professor and, later, associate department head of the university’s Department of Food, Bioprocessing and Nutrition Sciences. As the department’s distinguished undergraduate professor, and coordinator of its undergraduate food science program, he taught and conducted research on transport phenomena associated with food and beverage processing. This area studies the effect of heat, mass and momentum transfer on food safety and quality preservation, among other potential impacts. Farkas’ research publications have accumulated more than 2,200 citations in peer work. His areas of expertise include food process engineering and the thermodynamics of phase-change heat transfer associated with moving boundary problems.

Photos of UD President Dennis Assanis and Eleni Assanis outside their home in December of 2020.

Dennis Assanis is the 28th President of the University of Delaware. He was elected to the position by the UD Board of Trustees on Nov. 18, 2015. He took office June 6, 2016, and was formally inaugurated Dec. 7, 2016.

Dr. Assanis is a distinguished educator with a wide range of academic leadership experience and a worldwide reputation as a scholar and expert in both fundamental and applied studies of internal combustion engines and energy systems. In 2019, Dr. Assanis was named to the new National Commission on Innovation and Competitiveness Frontiers, an initiative of the nonprofit and nonpartisan Council on Competitiveness. 

Before coming to UD, Dr. Assanis served as provost and senior vice president for academic affairs at Stony Brook University and as vice president for Brookhaven National Laboratory Affairs. He previously taught and conducted research at the University of Michigan and the University of Illinois at Urbana-Champaign.

Born and raised in Athens, Greece, Dr. Assanis earned his Bachelor’s Degree in Marine Engineering from Newcastle University in England (1980). At the Massachusetts Institute of Technology, he earned three Master’s Degrees: Naval Architecture and Marine Engineering (1982), Mechanical Engineering (1982) and Management (1986). Also at MIT, he earned a Ph.D. in Power and Propulsion (1985). 

In 2023, Dr. Assanis was recognized by Newcastle University with its Alumni Impact Award. 

Dr. Assanis and his wife, Eleni, have two adult sons, Nicholas and Dimitris.


Erik Ervin

Dr. Erik Ervin is Chairperson of the Department of Plant and Soil Sciences and a Professor of Turfgrass and Horticultural Systems at the University of Delaware. He is an Emeritus Professor at Virginia Polytechnic Institute and State University. He is also a Fellow of the American Society of Agronomy. Dr. Ervin received his PhD from Colorado State University and a B.S. in Horticulture from Iowa State University.


Robin Morgan recently retired from the University of Delaware after serving for 38 years on the faculty of the Department of Animal and Food Sciences. Her research focus was on Marek's disease, and she enjoyed pursuing fundamental laboratory studies as well as working with the poultry industry to improve disease control. During her academic career, she advised many students and taught courses in molecular biology, genetics, and microbiology. Over the last two decades, she served in various administrative capacities, including two terms as Dean of the College of Agriculture and Natural Resources, Chair of the Department of Biological Sciences, and Provost of the University of Delaware. She continues to stay connected to UD as an Emeritus Professor, and enjoys working with Longwood Gardens, travelling, and spending time with family and friends in her retirement.

Yan Jin is the Edward F. and Elizabeth Goodman Rosenberg Professor of Soil Science at the Department of Plant & Soil Sciences and Francis Alison Professor at the University of Delaware (UD). She received her PhD in Environmental Toxicology from University of California, Riverside. Her research interests include measurement, modeling and interpretation of mass transport and transformation in soil and other environmental systems, with special focuses on colloidal (virus, nanoparticle) interactions with various interfaces and colloid transport in porous media, biophysical processes in the rhizosphere, the role of preferential flow in biogeochemical processes. She is the 2015 recipient of Don and Betty Kirkham Soil Physics Award, the first woman to receive the prestigious international award in her field and she is the inaugural recipient of UD’s College of Agriculture and Natural Resources Excellence in Research Award in 2018.  She was elected Fellow of Soil Science Society of America (SSSA) in 2008, served as Chair of the SSSA’s Soil Physics & Hydrology Division in 2019, and delivered the 2023 Nyle C. Brady Frontiers of Soil Science Lecture at the ASA, CSA, SSSA International Annual Meeting.

RSCH - EPSCoR Program - Amy Slocum - 07.20.23

Amy Slocum serves as the Director, Delaware Established Program to Stimulate Competitive Research (EPSCoR). She has over 26 years of grants management and administration experience. She received her doctorate degree in 2006 in Education, Policy, Leadership and Administration and a Master Degree in Public Administration in 2000 both from the University of Delaware. Amy has served as the pre and post award grants manager including sub-award monitoring, accounting, and reporting, and facilitating economic development initiatives with partners both within and outside the University of Delaware. In her role as the pre-post award administrator she has managed and facilitated more than 62 interdisciplinary federal projects (including Delaware EPSCoR programs) totaling $150 million that bridge science and society.  She has worked alongside Donald Sparks since 1999.

Carski is a Ph.D. from UD in 1986 and was Don Spark’s second Ph.D. student). He joined DuPont in 1986; retired in 2018, after 32 wonderfully fulfilling years with DuPont Crop Protection (also known as Corteva Agriscience). His various roles included Global Registration Strategic Portfolio Manager, Six Sigma R&D Project Manager, Global Registration Product Manager, Research Manager - Environmental Fate, and Principal Investigator – Environmental Fate.

Through ShoreRivers, Carski protects and restores MD’s Eastern Shore waterways. His roles include Governing Board, Ag Committee, Watershed Advisory Board, bacteria and SAV monitoring programs, and participant in various other programs. Janet and I live, boat, kayak, fish and hunt on the Eastern Shore, and want to contribute to restoring and maintaining the health of this special watershed. ShoreRivers offers the perfect opportunity to put our resources and experiences to work, ensuring sound science informs decision making, to improve the health of Eastern Shore rivers and creeks, and ultimately the Bay.

He serves on the University of Delaware External Advisory Boards for the College of Agriculture and Natural Resources and the Delaware Environmental Institute (DENIN). Also, he remains connected and supports UD via DENIN graduate student fellowship, ShoreRivers/DENIN student internship, named rooms in Harker Interdisciplinary Science and Engineering Lab and Worrilow Hall, and the Carillon Circle.

Michael Stapleton has been a Professor of Environmental Chemistry in the Department of Chemistry at Slippery Rock University of Pennsylvania (SRU) for twenty-eight years. During that time, he has served on several major university-wide committees as the coordinator of the Environmental Science Program and chair of the Department of Environmental Geosciences. His main area of research is the occurrence, monitoring, and treatment of Acid Mine Drainage (AMD) in the headwaters (72 sq km) of the Slippery Rock Watershed. 

Derek Peak is a Professor of Environmental Soil Chemistry in the University of Saskatchewan Department of Soil Science. His academic background includes a Ph.D. from the University of Delaware in Environmental Soil Chemistry and a B.Sc. in Environmental Management Systems from Louisiana State University. His research group uses a wide range of laboratory and molecular-scale techniques to probe chemical processes in soils from the nano to ecosystem scales. He has been an active synchrotron user for 20 years, primarily at the Canadian Light Source. His overall research program focuses on using advanced techniques to manage soil resources more effectively. Major research themes include understanding the fate and transport processes that control nutrient and contaminant availability in soils, sustainable agricultural development in developing countries, effectively remediating and rehabilitating soils contaminated because of natural resource extraction and developing new spectroscopic techniques for analysis of environmental samples. The Peak group has published 103 peer-reviewed papers and 6 book chapters. He has also trained 14 M.Sc. students, 5 Ph.D students, and 7 post doctoral researchers. His research quality has been recognized with several awards, including the USask Global Research Leadership Award, College of Agriculture and Bioresources Dean’s Award for Research Excellence, and twice received NSERC’s Discovery Accelerator Supplement (~top 2% NSERC applicants). Peak also serves on Environmental Science and Technology’s editorial advisory board, is an associate editor of SSSAJ, and is the chair-elect of Soil Chemistry division of SSSA.

Maarten Nachtegaal is currently Private Lecturer at ETH Zurich and Group Leader at the Paul Scherrer Institute (PSI), as Adjunct Professor in the Department of Chemistry and Applied Biosciences at ETH Zurich. Nachtegaal is an expert on beamline operando X-​ray measurements. His work combines inorganic chemistry and chemical physics, with a focus on further developing synchrotron techniques in order to investigate the structure of catalysts and improve catalytic processes. Nachtegaal is highly regarded in his field and is a dedicated and successful supervisor and mentor.

David McNear is a Professor in the University of Kentucky Department of Plant and Soil Sciences. He received a Ph.D. in Environmental Soil Chemistry from the University of Delaware. His research explores the biogeochemical processes occurring at the soil-water-plant interface (also known as the Rhizosphere) and how these processes influence the mobility and bioavailability of trace elements in natural systems.

Siebecker received his Ph.D. in Environmental Soil Chemistry. During his Ph.D. and postdoctoral studies, his research focused on the behavior of heavy metals and how they react with clay minerals in soils. He has worked with serpentine soils, agricultural soils, contaminated soils, as well as sediment cores from estuaries. His research interests include the behavior of potentially toxic elements as well as environmentally problematic plant nutrients in soils, particularly as impacted by climate change (e.g., flooding and drying cycles).

Ongoing research activities in his group include analysis of the fate and transport of arsenic in contaminated soils, the surface chemical reactions of potassium onto metal oxide minerals, and the cycling of phosphorus, zinc, and iron in soils impacted by waste from animal production facilities. Often his group measures the rates (kinetics) of soil chemical reactions (e.g., sorption/desorption/redox) and couples experiments in the laboratory with spectroscopic analysis via synchrotron radiation.

Audrey Gamble is an Associate Professor in the Department of Crop, Soil and Environmental Sciences at Auburn University. She received her PhD in Environmental Soil Chemistry from the University of Delaware in 2017. Dr. Gamble’s research program focuses on identifying conservation practices to improve soil quality and sustainability in crop production systems. This includes assessment of short-term soil health indicators to predict long-term improvements in soil health and sustainability. She currently serves as past-president of the American Society of Agronomy-Southern Branch and chair of the Southern Cover Crops Council.

Kate Szerlag’s journey into the realm of soil phosphorus research was deeply rooted in her upbringing on a dairy farm in central Massachusetts. As a non-traditional student, her pursuit of higher education began with an associate degree from Quinsigamond Community College in Massachusetts, followed by both a Bachelor's and Master's degree from the University of Massachusetts, Amherst. During her undergraduate years, Kate delved into soil phosphorus chemistry while working at the UMass Soil and Plant Tissue Testing Lab, laying the groundwork for her future endeavors. Her Master's thesis further honed her expertise in soil phosphorus chemistry.


Continuing her academic journey, Kate completed her Ph.D. in Plant and Soil Sciences at the University of Delaware under the guidance of Dr. Don Sparks, a period during which she discovered a new passion for synchrotron-based radiation techniques. This innovative approach allowed her to explore phosphorus speciation in high legacy phosphorus agricultural soils, marking a significant milestone in her research career.


Following the successful defense of her dissertation, Kate embarked on a new chapter as an Assistant Professor of Soil Science and Environmental Chemistry at Westfield State University in Massachusetts. However, in August 2023, she made a pivotal move to Texas A&M University, assuming the role of Assistant Professor of Soil and Water Chemistry. At Texas A&M, Kate continues to expand her research horizons while still maintaining her focus on soil phosphorus chemistry and speciation, leveraging the power of synchrotron-based radiation. Guided by her experiences in the Sparks Lab, Kate is hoping to carve out a promising and impactful career.

Belowground Dynamics of Recently Fixed Plant Carbon in a California Annual Grassland

In the 2023 edition of the Sparks Lectureship, Mary Firestone discussed plant roots and the organisms that surround them—a primary source for stabilized soil organic carbon (SOC). This characteristic of the terrestrial C cycle is critical to C storage, soil water holding capacity, nutrient provision, and the management of soil health. While grassland soils have a large capacity to store organic carbon (C), few field-based studies have quantified the movement of plant-fixed C into soil and its persistence belowground over multiple years. We tracked the fate of plant-fixed C in the field following a five-day 13CO2 labeling of a Northern California annual grassland, characterizing the soil C pools over a period of two years. Our results indicate that newly fixed C moved into soil within days and was associated with the soil mineral fraction within weeks. While most of the annual plant C input in these grasslands cycles rapidly (<2-year timescale), a sizeable proportion (about 23% of the 13C present at day 0) persisted in the soil for longer than 2 years. 

The recording can be found on the lectureship media channel.

Microplastics as Contaminants in the Environment: Impact on Plant-Water Relations and Cadmium Uptake

Microplastics are a major source of pollutants in soil and marine ecosystems. Microplastics in the aquatic environment have been widely studied, but microplastics in the terrestrial environment have been less studied, and essentially no information exists concerning the water relations of plants grown in soil with microplastics. This lecture will describe an experiment with microplastics in soil. The first objective of the experiment was to determine the growth, stomatal resistance, and evapotranspiration rate of wheat when grown in soil with microplastics. Because microplastics can be a vector for toxic trace-element uptake, the second objective of this experiment was to determine the uptake of cadmium (Cd) to see if they enhanced its uptake. The results showed that the microplastics reduced growth, increased stomatal resistance, and reduced evapotranspiration. They were a potent vector for the transport of Cd to wheat leaves.

This event took place on Thursday, April 14 at the Gore Recital Hall.

The recording can be found on the lectureship media channel.

Donald L. Sparks Distinguished Lectureship in Soil and Environmental Sciences

In 2019, Dr. Donald L. Sparks, a longstanding professor of soil and environmental chemistry in the Department of Plant and Soil Sciences at the University of Delaware, made a generous multi-year gift to create the Donald L. Sparks Distinguished Lectureship in Soil and Environmental Sciences. By creating this fund, Dr. Sparks' goal is to bring renowned thought leaders, from across multidisciplinary backgrounds, to the University of Delaware annually in order to share insight and research around the latest topics in soil and environmental sciences.