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.


Experimental watershed provides new insights, rich educational experience

June 25, 2012 under CANR News

Six years and about 4,000 water samples later, an outdoor experimental watershed laboratory established by University of Delaware faculty members Shreeram Inamdar and Delphis Levia at Fair Hill, Md., is now producing valuable data and novel insights into how water and chemicals move through the forest canopy, soils and watersheds, and how future climate change may impact or alter such responses.

Inamdar, associate professor in the Department of Plant and Soil Sciences, has investigated the role of soils, streams, and watersheds in leaching water and nutrients, while Levia, professor in the Department of Geography, has studied the interactions of atmosphere and the forest canopy in leaching water and nutrients. Together, they have provided a complete picture of watershed hydrology and biogeochemistry.

The two were awarded a National Science Foundation (NSF) grant in 2008 to study the mechanisms behind the leaching and exports of carbon and nitrogen from watersheds and how these chemicals evolve as they change in space — traveling through the forest canopy, soils, and stream drainage network — and as they change in time through the different seasons.

Both carbon and nitrogen are important elements of natural ecosystems but in excess can cause problems. Excess dissolved organic carbon in runoff and drinking water supplies can result in the production of cancer-causing byproducts when the water is chlorinated for disinfection. Elevated nitrogen concentrations, such as nitrate, ammonium and the organic forms, can result in degradation of water quality and the production of algal blooms in stream, ponds, and lakes and large water bodies like the Chesapeake Bay, making them unfit for swimming, fishing and other recreational activities.

Network data collection

To characterize the movement of water and chemicals in the watershed, Inamdar and Levia implemented an intensive network of multiple, state-of-the-art, automated instruments, sensors and sampling devices that record rainfall and weather data, streamflow runoff, groundwater elevations, soil moisture and water quality. These sensors have been recording data at a frequency of 5 to 30 minutes for the past six years.

Automated water samplers trigger whenever needed, even in the middle of the night, in response to rain events or extremely large events such as hurricanes Irene in 2011 and Nicole in 2010. Such intensive, high-frequency data, combined with laboratory analyses, have provided invaluable insights into watershed functioning and response.

For example, 30-minute groundwater level and stream runoff data has captured the daily fluctuations of water in summer in response to the evaporation from trees and soils, peaking during mid-day and reaching a minimum just before dawn.

Similarly, water samples collected during Hurricane Nicole, which occurred after an extended dry summer period, revealed very unusual patterns in carbon concentrations and quality in stream runoff, trends that were not seen during regular storms.

“What we found was a larger amount of bioavailable carbon coming out during extreme storms,” said Inamdar. “When I say bioavailable, that means the carbon can be easily consumed by aquatic organisms, so the more bioavailable carbon or nitrogen in your streams or water bodies, the greater the chances for algal growth.”

Inamdar went on to explain that the big storms, especially the ones that come after droughts, “flush out a lot of this material into the creeks and rivers which could eventually end up in the Chesapeake Bay or larger water bodies and cause potential problems.”

Climate change scenarios suggest that storms will become more intense with dry intervening periods similar to the conditions associated with the Hurricane Nicole event, and thus studying such extreme events provides a critical window into the future.

Sampling for multiple years has provided insights into how water chemistry changes with seasons. These measurements have allowed for the researchers to investigate how unique seasonal events – such as autumn leaf fall or spring emergence — alter water quality in the stream. These episodic events are also referred to as “hot moments” for their short time span, but disproportionate impact on water and ecological processes.

With regard to autumn leaf fall, Inamdar said, “When leaves fall into the stream, they are providing a carbon source, so the moment they fall into the stream, the bacteria kick in and start consuming the nitrogen. So the stream’s inorganic nitrogen drops as the autumn leaf fall occurs.”

Inamdar cautioned that if climate change were to occur and alter the seasons, it could disrupt these processes. “With the autumn leaf fall and the spring leaf emergence, climate change is going to change the dynamics of how these ecological process effect the carbon and nitrogen cycling in watershed systems.”

The researchers also look at where the carbon and nitrogen comes from, as well as the individual flow paths they take on their way to the stream. “What we are seeing is a lot of the carbon is coming from the forest floor, where the leaves have accumulated and are decaying and decomposing,” said Inamdar, noting that they are seeing a lot of the carbon and nitrogen being transported by surface flow paths.

The group not only looked at the amounts of carbon being put into watersheds, they also studied the carbon quality being put into the watersheds. “Is the carbon easily degradable? Is it bioavailable? We are making that level of distinction as well,” said Inamdar, noting that fresh leaves are extremely degradable while a substance like the tree bark and stems in the forest floor take a longer time to degrade.

Teaching resource

For many undergraduate and graduate students, the outdoor watershed laboratory has served as an extremely valuable learning experience. A total of 12 graduate and undergraduate students have used the Fair Hill watershed site for their research. Six different courses from departments across the University have also used the watershed site for hands-on field visits to study the characteristics and functions of watersheds, soils, streams, and the forest canopy.

European and U.S. scientists and NSF program officers visited the Fair Hill site in November 2011 as a part of the International Critical Zone Observatory meeting, and Inamdar and Levia have also been successful in using the site as a recruitment tool for new students.

The study site is used for outreach activities with the Fair Hill Nature Center, a non-profit entity located near the study site, responsible for educating about 8,000 kindergarten through eighth grade students annually about responsible environmental stewardship. Levia has shared his knowledge of the meteorological station with the general public through the Nature Center and led field trips to highlight how water and soils can be studied in a natural setting.

The Fair Hill watershed site is now helping spawn new ideas and research partnerships. For example, Inamdar intends to study how invasive plants may be invading mid-Atlantic forested landscapes and how they may be altering the soil and water chemistry of these important ecosystems, while Levia plans to seek additional funding to establish a flux tower in the forest to study atmospheric-canopy gas exchange.

Article by Adam Thomas


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


Nov. 10: UD, state to host issues forum about Chesapeake Bay

November 3, 2010 under CANR News, Events

The Chesapeake Bay is a national focal point for water quality issues. New environmental regulations will require Delaware and the other five bay states — Maryland, Virginia, West Virginia, Pennsylvania, and New York — and the District of Columbia to significantly reduce pollution entering the bay and its tributaries.

These rigorous federal and state program aims to restore the bay’s water quality by 2025.

Because the two main pollutants that are under consideration are nitrogen and phosphorous, agricultural entities in Delaware and the other bay states have a vital role in this process.

On Wednesday, Nov. 10, Alpha Gamma Rho fraternity, the Delaware Department of Agriculture and the University of Delaware College of Agriculture and Natural Resources will host an agricultural issues forum to address agricultural and environmental concerns surrounding the health of the Chesapeake Bay as it relates to water quality.

“The Intersection of Agriculture, the Environment and the Chesapeake Bay” will be held in the Trabant University Center Multipurpose Room A from 7-9 p.m.

“The goal of this event is to bring awareness to one of the major environmental issues in our area,” says Craig Parker, president of Alpha Gamma Rho. “We hope that UD students, faculty, and other community members will join us to learn about the issues from everyone involved.”

The program will be moderated by Ed Kee, secretary of the Delaware Department of Agriculture, who is also a CANR alumnus and former UD employee.

Kee will be joined by science and regulatory advisors Rick Batiuk, science adviser for the Chesapeake Bay Program, and Kathy Bunting-Howarth, director of the Division of Water at the Delaware Department of Natural Resources and Environmental Control.

Industry and government panelists for the evening include:

* Steve Schwalb, vice president, Environmental Sustainability, Perdue Farms;
* Shawn Garvin, regional administrator for Region III, U.S. Environmental Protection Agency (EPA);
* Dave Baker, farmer and member of Delaware Nutrient Management Commission; and
* Jim Borel, executive vice president, DuPont.

The forum will conclude with networking and free UDairy Creamery ice cream.

For more information call (302) 831-1355 or send email to [kvo@udel.edu].