Jaisi laboratory tracks chemicals in water, farmland throughout Mid-Atlantic

February 27, 2013 under CANR News

Deb Jaisi studies phosphorus in his labUniversity of Delaware researcher Deb Jaisi is using his newly established stable isotope facility in the Environmental Biogeochemistry Laboratory (EBL) to find the fingerprints of isotopes in chemical elements — specifically phosphorus — in order to track sources of nutrients in the environmentally-sensitive Chesapeake Bay, other bodies of water and farmland throughout the Mid-Atlantic.

Jaisi, assistant professor in the Department of Plant and Soil Sciences in the College of Agriculture and Natural Resources, explained that he and his research team are currently working on many projects in the EBL, including two that are funded through seed grants, one focusing on terrestrial phosphorus sources and the other on marine phosphorus sources in the Chesapeake. One of those grants is from the UD Research Foundation (UDRF) and is titled “Role of Non-terrestrial Phosphorus Sources in Eutrophication in the Chesapeake Bay.”

For the project, Jaisi and his team of graduate students and post-doctoral researchers are looking at different sources of phosphorus in the Chesapeake Bay over time. Working with Old Dominion University, the team has been provided sediment core samples taken from bay that spans several decades of sediment accumulation and is extracting the phosphorus from those sediments and measuring the isotopic composition of phosphate.

Jaisi explained that they do this in order to identify the sources of phosphorus and see how those specific sources have changed over time in the bay, which could be important information in seeking to understand their impact on the water quality in the bay.

Jaisi said that it is important to study phosphorus because it “is one of the most important nutrients for any living being. In most cases, this is a limiting nutrient and what that means is that it controls the growth or how much life you can have out of that nutrient.”

Jaisi continued, saying, “DNA and RNA are made of phosphorus backbone — so our bones are made of phosphorus, our teeth are made of phosphorus. You can name every part of the body and it has phosphorus, and the same is true for any other living being.”

While phosphorus is important to life, too much phosphorus — particularly in bodies of water — can cause serious ecological problems, leading to algae blooms and oxygen deficiency.

 

 

Jaisi’s group also has a U.S. Department of Agriculture (USDA) grant to compare the phosphorus plants take up to the phosphorus that is present in fertilizers, while also tracking any excess fertilizer that is used by growers to see where that fertilizer goes.

For farmers or homeowners applying phosphorus-rich fertilizer, Jaisi said it is not clear how much phosphorus from fertilizer is being taken up by plants. “We don’t explicitly understand how much phosphorus is needed or where the phosphorus ends up,” he said, adding that a phosphate oxygen isotope fingerprint tool can provide a more detailed picture. “We hope to provide a better resolution of phosphorus fate – that this phosphorus fraction leaked out of the soil and went to the ground or surface water, and this fraction is taken up by plants.”

The researchers are also looking at how rivers carry phosphorus and how far they can trace certain sources of phosphorus in a river. This research is being done in Maryland, and Jaisi explained that the group is looking at how phosphorus is leached out of soil and carried into creeks and rivers. “We are taking samples along a creek and in sediments to see how far the phosphorus can go. Does it retain somewhere in the river, or is it exported to the Chesapeake Bay?”

Isotope fingerprinting

To find the fingerprints of isotopes, Jaisi uses a machine known as a stable Isotope-Ratio Mass Spectrometer (IRMS).

Jaisi said that because “different sources may have different isotopic composition,” if he and his research team can figure out an element’s isotopic composition, they can identify how that element has impacted the environment.

“For example, if the phosphate is originating from a wastewater plant, that is one isotopic composition or one type of fingerprint. Then, compare that fingerprint to what comes out of the fertilizers, and to what comes out of soil erosion from the geological processes — that kind of phosphate has other isotopic compositions.”

The currently installed IRMS has three different components, each capable of measuring a specialized element. One is used for phosphate oxygen isotopes, one for carbon and nitrogen isotopes and one for water and carbonates. The three machines feed into the mass spectrometer via a synchronizing unit called ConFlow.

Jaisi said that such machines used to measure phosphate oxygen isotopes are not very common, with only a handful worldwide.

Although his group mainly focuses on phosphorus, the EBL and the equipment is available to other researchers at the University and outside, and can be used to measure for stable isotopes of nitrogen, carbon, sulfur and other light elements.

For more information on Jaisi’s lab, visit the website.

Article by Adam Thomas

Photos by Danielle Quigley

Video by Adam Thomas and Danielle Quigley

This article can also be viewed on UDaily.

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Deb Jaisi awarded UDRF project funding

June 13, 2012 under CANR News

The University of Delaware Research Foundation (UDRF), a private corporation chartered in 1955 to support UD research, has funded 11 new projects in science and engineering on the UD campus.

Each project is supported by a $35,000 grant — a combination of $25,000 from UDRF and $5,000 each from the provost and the researcher’s dean. The grants seed original, high-priority, “proof of concept” studies that are designed to lay the groundwork for future proposals to external agencies such as the National Institutes of Health, the National Science Foundation and others.

“Typically, only a small percentage of the competitive research proposals submitted to federal agencies are funded,” said Mark Barteau, senior vice provost for research and strategic initiatives. “UDRF provides early career University of Delaware researchers with a critical opportunity to test new ideas and collect data that may give them a competitive edge later on, as they develop external proposals.”

Deb Jaisi, assistant professor of plant and soil sciences, has received UDRF funds to study the Chesapeake Bay. The Chesapeake Bay suffers from varying degrees of eutrophication, a reduction in water quality due to excessive nutrients. Jaisi will analyze a key nutrient, phosphorus, in bay sediment cores and water samples to determine the changes of terrestrial phosphorus phases over time and their relationship to hypoxia, or oxygen depletion. Oxygen isotopes in phosphate will help identify the sources and biogeochemical cycling of phosphorus in sediment and the water column, yielding data useful to nutrient management programs.

To read about the other UDRF funded projects, visit UDaily.

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UD’s Jaisi wins ORAU Powe Award to track down nutrient pollutant in Chesapeake

May 9, 2012 under CANR News

Too much of a good thing can kill you, the saying goes.

Such is the case in the Chesapeake Bay, North America’s largest estuary, where an overabundance of nutrients fosters the formation of an oxygen-starved “dead zone” every summer. In its annual health report card last year, the bay earned only a D+.

Deb Jaisi, an assistant professor of plant and soil sciences at the University of Delaware, wants to seek out the sources of a key nutrient so excessive that it has become a pollutant in the Chesapeake Bay — phosphorus (P).

Jaisi wants to literally get to the bottom of this nutrient’s influx by analyzing the phosphorus present in a set of sediment cores extracted from the seafloor of the upper bay, middle bay and lower bay. The cores offer a glimpse into the geological and environmental record of approximately the past 75 years.

The Oak Ridge Associated Universities (ORAU), a consortium of 105 major Ph.D.-granting academic institutions, has high hopes for Jaisi’s research. Recently, Jaisi was one of 30 scientists selected nationwide to receive ORAU’s Ralph E. Powe Junior Faculty Enhancement Award. The award is intended to enrich the research and professional growth of young faculty and result in new funding opportunities.

Jaisi will receive $5,000 in seed funding from ORAU and $5,000 in matching funding from UD to launch his Chesapeake study.

According to Jaisi, phosphorus in the bay comes from three primary sources: the land, the ocean, and the buried sediments from where phosphorus is remobilized and reintroduced into the bay. However, current nutrient management efforts focus solely on reducing inputs from land.

“The contribution of these three major sources of phosphorus has varied since colonial times,” says Jaisi, who joined the UD faculty last year. “The prevailing notion that the increase in terrestrial phosphorus alone is the tipping point for the bay’s eutrophication is questionable.”

When his new state-of-the-art isotope lab is completed in UD’s College of Agriculture and Natural Resources this summer, Jaisi and his team of graduate students and postdoctoral researchers will begin using a prized new instrument called a thermo-chemical elemental analyzer (TC/EA) coupled to an isotope mass spectrometer (IRMS) to assess the presence and levels of the distinctively different forms, or isotopes, of phosphorus.

Each phosphorus source, from fertilizers used on land, to wastewater effluents, seafloor sediments, or the ocean, usually has a distinctive isotope composition or “signature” retained in the sediment cores. By comparing data from the same historical period in the sediment cores, Jaisi and his research group will be able to identify the relative contributions of different phosphorus sources over time.

“The strength of this work is that it applies the natural abundance of stable isotopes to ‘fingerprint’ the phosphorus sources for the first time in the Chesapeake Bay,” Jaisi notes. “We’ll be able to see how much phosphorus is derived from the land versus from the ocean. Over time, the analysis will reveal the real culprit in the Chesapeake Bay’s nutrient overenrichment.”

Jaisi says he hopes the work will expand knowledge of the estuary’s nutrient diet and provide information useful to resource managers in controlling phosphorus overloads. He envisions the eventual development of detailed nutrient maps of the bay, as well as the rivers that drain into it.

Originally from Nepal, home of Mount Everest, Jaisi began using isotopes to explore nutrient issues as a postdoctoral fellow at Yale University. He says the University of Delaware has provided a perfect fit for his research.

“This is an area where phosphorus is a big and hot issue,” he says. “Here, the bay and my laboratory are side by side.”

Article by Tracey Bryant

Photos by Kathy F. Atkinson

This article can also be viewed on UDaily

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Delaware EPSCoR announces 2012 seed grant recipients

March 7, 2012 under CANR News

The Delaware EPSCoR program has awarded seven seed grants to University of Delaware faculty whose projects address current environmental issues within the state.

EPSCoR, the Experimental Program to Stimulate Competitive Research, is a federal grant program of the National Science Foundation (NSF) that helps states develop their research capabilities so that they may compete for further federal funding.

Seed grants are typically in the $50,000 range and help researchers set the stage for applications to larger federal funding programs. Seed grant proposals are solicited annually during the fall semester. The selections were made by a committee of five senior faculty affiliated with the Delaware EPSCoR program and two external reviewers representing the Delaware Department of Natural Resources and Environmental Control (DNREC). This year’s funded projects are as follows:

Microbes that remove arsenic from rice

Rice is a staple in diets across the globe, but it is commonly contaminated by arsenic (As) in many developing nations. To solve this problem, University of Delaware scientists Harsh Bais and Janine Sherrier of the Department of Plant and Soil Sciences have proposed that the inoculation of rice with the bacterium EA106 will reduce arsenic accumulation within the edible portion of the plant, simultaneously improving quality and yield. Arsenic-contaminated rice represents a significant health risk to millions of people worldwide; in their research Bais and Sherrier plan to “systematically dissect the overall mechanism in As absorption and translocation in rice.” Their efforts will further probe the field of plant-microbial processes and how they may be used to agricultural advantage.

Impact of terrestrial phosphorus on eutrophication in the Chesapeake Bay

Principal investigator Deb Jaisi, assistant professor, and Donald Sparks, S. Hallock du Pont Chair of Soil and Environmental Chemistry, both of the Department of Plant and Soil Sciences, will investigate the concentrations of terrestrial and nonterrestrial phosphorus (P) input into the Chesapeake Bay over time. The prevailing notion is that the level of nonterrestrial P has remained constant since early civilization, and thus terrestrial P is the sole culprit in the eutrophication (increased concentrations of nutrients which result in algae blooms and fish kills) of the Chesapeake Bay. However, observed changes in the bottom water environment indicate that this is unlikely. Their study will influence future management strategies to limit nutrient pollution, with regulations possibly addressing both terrestrial and nonterrestrial P input. Sparks is director of the Delaware Environmental Institute.

Article by Jacob Crum

Photos by Ambre Alexander and Kathy F. Atkinson

For the complete article and list of seed grant recipients, view the full story on UDaily

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Deb Jaisi joins the CANR faculty

June 8, 2011 under CANR News

Deb Jaisi, assistant professor of environmental biogeochemistry, has joined the faculty at the University of Delaware’s College of Agriculture and Natural Resources.

Jaisi said that he decided to come to the University of Delaware because he was looking for a university that was well established but also tries to promote new ideas with new faculty where it feels like a fresh start. His particular area of research expertise also meshed well with what is currently going on in the state of Delaware and the surrounding area.

“My research is primarily in phosphorous geochemistry, and when I talked to Dr. Sparks during my interview I realized, ‘phosphorous is such a big issue here in DE’ with regards to the agricultural farms, Chesapeake and Delaware Bays.”

Jaisi also said that, “Sometimes a job interview becomes an important experience that invigorates your idea and instills more scientific curiosity on what you have done or are doing. That makes this particular job even more exciting. My science, which is isotope geochemistry, can really help to explore more and identify how and why the phosphorous has been released to the surface water and ground water. With that being said, the ‘applied’ aspect of my research aims to find out the culprit of phosphorus release in these areas.”

Another big reason that influenced Jaisi’s decision to come to UD was the fact that he wanted to collaborate with renowned professors, such as Donald Sparks, S. Hallock DuPont Professor of Plant and Soil Sciences, professor of chemistry and biochemistry and professor of civil and environmental engineering, and Tom Sims, deputy dean of the College of Agriculture and Natural Resources and the T.A. Baker Professor of Plant and Soil Sciences, and potentially with other professors in the area of plant-soil interactions. Said Jaisi, “To be at a college with Dr. Sparks, whose legacy I highly respect, is a rather great opportunity.”

Jaisi also said that Delaware is a great place to raise kids, “it’s very close to big cities, but it’s not suffocating like staying in big cities. It’s a very, very nice place.”

After growing up in Nepal and earning his undergraduate degree in geology from Tribhuvan University, Jaisi went on to Thailand where he received his Master’s degree in engineering from the Asian Institute of Technology, before traveling to Miami University in Ohio to receive his Ph.D. Jaisi also conducted his post-graduate work at Yale University.

Jaisi did not teach a course last semester and explained that his appointment is mostly for research. He does, however, plan to teach one course each year on his own and co-teach another course with a fellow faculty member.

As for the research side, Jaisi has plans to establish a stable isotopes laboratory, which he describes as a “very intensive process” that he expects will take up to about a year to complete, with the laboratory hopefully being set up by the end of 2011.

Article by Adam Thomas
Photo by Danielle Quigley

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