Much like criminal forensic scientists use fingerprints to identify guilty parties at crime scenes, the University of Delaware's Deb Jaisi utilizes isotopic fingerprinting technology to locate the sources of phosphorus compounds and studies the degraded products they leave behind in soil and water.
Jaisi, an assistant professor in the Department of Plant and Soil Sciences in UD's College of Agriculture and Natural Resources (CANR), recently received a highly prestigious National Science Foundation Faculty Early Career Development Award, and said that he will use the five-year, $570,000 grant to further his source tracking research, looking specifically at the sources and fate of phytate, the most common organic phosphorus in soils.
In addition, an educational component of the research will contribute to the development of an Environmental Forensics and Society course at UD, enhance curricula at Delaware Technical Community College and develop an environmental forensics summer camp as part of the 4-H Positive Youth Development and mentoring organization summer activities.
Of the award and Jaisi's research interests overall, CANR Dean Mark Rieger said, "In just five short years at UD, Dr. Jaisi has become a national authority in isotope tracking methodologies, and he applies them to one of the most important issues at the ag-environment nexus: the sources and fates of phosphorus in the environment. This award is not only recognition of his prior impact on the field, but a testament to his future potential as a leader in soil biogeochemistry."
Janine Sherrier, chair of the Department of Plant and Soil Sciences, said that "Dr. Jaisi's research provides a new dimension and a complementary approach to our department's research program on phosphorous cycling in the environment."
Natural versus human contribution
Surface water eutrophication and bottom water dead zones in the Chesapeake Bay have been an issue for decades.
When it comes to phosphorous sources and biogeochemical processes that contribute to the water quality in the Chesapeake, Jaisi said that the quantitative identity and original sources of phosphorous are still not fully understood.
"A molecular level understanding of the sources and processes that impact water quality is something I am interested pursuing in my career," he said.
This research will look at the phytates, which are phosphorus reserves in grains and are the most common forms of organic phosphorous in the environment.
"Monogastric animals like a pig or a chicken cannot digest phytate in their grain-based diet, so it's going to end up in manure. The application of manure in agriculture soil causes a portion of it to leach out of the soil and eventually finds its way to open waters," said Jaisi.
The other major form of phytate in the environment comes from plant leaves. While plants have an unusually small amount of phytate, the large numbers of leaves that fall off in early fall make this source of phytate abundant, as well.
"Using isotope fingerprints of phytate, we can identify whether phytate is derived from a plant, which is a natural process, versus manure, which is related to anthropogenic activity," Jaisi said. "Distinct seasonality of both processes allows us to provide precise information not only on the source but the exact residence time of phytate and its products in the environment. Understanding the role of the particular source of phytate on water quality is the primary information needed to devise appropriate water quality management."
The question of anthropogenic phosphorous loading versus natural phosphorous loading in the Chesapeake is one that Jaisi said gets asked a lot and that his research is central to answering.
"The question is not natural versus agriculture-driven, as both contribute, but how much does one source contribute with regard to the water quality," Jaisi said. "I am extremely lucky to work with a dynamic group of postdoctoral associates, graduate and undergraduate students on my team who are as committed to these problems as I am. Together we are dedicated to making a meaningful impact on science and society."
In addition to looking for the source of the phytate, Jaisi seeks to understand how one form of phytate transforms to the other form called "stereoisomers."
Specifically, Jaisi is interested in understanding if it is a biologically coded reaction or a chemical transformation. Since some of the stereoisomers are more stable than others, addressing the first question will unravel whether there is a yet unknown microbial process to synthesize them for yet unknown reasons.
In regard to the impact on water quality, Jaisi will also investigate the residence times of different products of phytate and stereoisomers in soil and water, which will help address the longstanding scientific question concerning phytate accumulation versus degradation and its environmental impacts.
Jaisi's research will split into controlled experiments in his laboratory and a field study in East Creek, a body of water that flows into the Chesapeake Bay in Crisfield, Maryland.
The resulting data and information on phytate pathways and processes could be useful to collective efforts by a series of federal, state, and local agencies involved in improving water quality including the Chesapeake Bay Program, such as the U.S. Geological Survey and the U.S. Environmental Protection Agency, which collectively develop Chesapeake Bay restoration plans.
One of the key elements of the NSF Career program is to enrich educational experiences and inspire students in science, technology, engineering and mathematics (STEM) fields.
The research will lead to the development of an Environmental Forensics and Society course at UD and enhance curricula at Delaware Technical Community College.
Lakshmi Cyr, instructional director and department chairperson of the biology and chemistry department at Delaware Tech, said that the collaboration between the two institutions, "provides enhanced training for DTCC program graduates, promotes student engagement, and eases students' transition to four year institutions. DTCC interns had very positive experiences working with Dr. Jaisi. They demonstrated improved laboratory skills and a greater understanding of the research process, which led to post-graduation success in their chosen careers or continued education path."
In addition, Jaisi is looking forward to the environmental forensics summer camp through the Delaware 4H program, in which approximately 200 students will take part, as he is passionate about environmental forensics in different dimensions from research to the course development and to the summer programs.
"A series of contaminants impacts human and environmental health and it could be a pesticide or another toxin or a heavy element. The unique way we approach the forensic question is we use source fingerprints to identify where did they come from and where do they end up? It is important we raise the public concern about environmental quality and our habitat. Thus, we're going to make them aware of how important it is to protect the environment where we live," said Jaisi.