Trees can help cities better prepare for severe weather events

November 21, 2012 under CANR News, Cooperative Extension

In the aftermath of Hurricane Sandy, many cities are taking a look at how they can better prepare for severe weather events. A low-tech – but effective – solution is to plant trees, says Sue Barton, ornamental horticultural specialist for the University of Delaware.

“A single mature tree can intercept several thousands of gallons of stormwater. Plant more trees in the right places and you can mitigate the impact of storm events,” says Barton.

She points to the research of David Nowak, a forester at the U.S. Department of Agriculture’s Northern Research Station in Syracuse, N.Y., who has analyzed the role that “urban forests” play in controlling runoff and flooding, reducing the costs of stormwater management facilities, and decreasing water pollution.

An “urban forest” doesn’t necessarily mean a tree-filled area the size of Central Park. Instead, researchers like Nowak look at the overall tree coverage in a community. The average urban tree canopy in the U.S. is 23 percent. But the tree canopy in the New Castle County metro area is estimated to be just 19 percent, and the city of Wilmington’s tree canopy is 16 percent.

“Philadelphia and Wilmington have experienced water overflow situations after decent-sized rains, not just storm events like Hurricane Sandy,” says Barton, a Cooperative Extension specialist and associate professor in the Department of Plant and Soil Sciences. “The stormwater management systems in these cities were engineered many years ago and they can’t handle the water flow after a big rain – which means raw sewage and other organic material bypasses the treatment plants and go directly into streams.”

Fixing antiquated stormwater systems isn’t cheap. “One of Nowak’s greatest contributions may be his research into the economic benefits of trees,” says Barton. “He came up with a way to put a dollar cost on how much trees can save a community. He looks at the cost of trees and tree maintenance relative to the costs of updating aging stormwater systems.”

In Wilmington, the Delaware Center for Horticulture (DCH) has been a driving force behind stormwater mitigation efforts that include planting trees and shrubs, establishing rain gardens and installing underground holding tanks. All three of these elements were included in a stormwater project at the Trolley Square Acme that was completed in June 2011.

The 9,000-square-foot project filters, slows and absorbs rain that falls on the roof of the Acme and its 1.42 acre parking lot. Comprised of 19 shade trees, more than 2,800 shrubs and smaller perennial plants, a rain garden, and underground holding tanks, the project captures an estimated 70 percent of the site’s annual rainfall, providing relief to the city’s combined stormwater and sewer system.

Gary Schwetz is a senior project analyst at DCH and was instrumental in the development and execution of the Acme project. His advice to those who want to use trees to intercept stormwater: “Think big.”

Schwetz doesn’t mean you need to plan a big project – like the 2,819 or so living things planted at the Acme — but that you need to include big trees.

“Large trees are better at absorbing rainwater and mitigating air pollution,” says Schwetz.  “A 20-foot tree will have eight times the environmental benefits of a 10-foot tree.”

Of course, it can be tough to grow a big tree in the narrow space between a city sidewalk and the street, or in a city backyard. It can even be tough for big trees to do well in public spaces like Rodney Square, which little by little has seen its grassy area reduced and covered by pavers and other impervious surfaces.

Schwetz and fellow DCH staffers worked on an innovative landscape project that will help big trees flourish at Rodney Square. Other partners were the city of Wilmington and the Delaware Department of Transportation.

What makes the project different, says Schwetz, is the use of a new structural cell technology as the planting medium. These milk-crate-like structural cells can support sidewalks and hold a high volume of good quality soil, creating conditions in which large trees should be able to thrive.

Rodney Square isn’t the only place the city of Wilmington has been planting trees lately. Some 250 trees were planted by the city in the last year and a half. And, one year ago, the city hired Mandy Tolino has its first-ever urban forest administrator.

“Trees and the green infrastructure improve water quality by helping slow water down during a storm, as well as by reducing erosion,” notes Tolino.

Recently, she has been involved in a pilot tree trench installation at Brown Burton Winchester Park, at 23rd and Locust streets. On the surface, this tree trench looks like an ordinary row of trees. But underground, the trench is lined with a permeable fabric and filled with gravel. During a rainstorm, water flows through a storm drain to the trench, where it’s stored in the empty spaces between the stones before slowly infiltrating into the soil below.

There will be a public dedication of the Rodney Square landscape project on Nov. 27 at noon. For more information, call the Delaware Center for Horticulture at 658-6262.

Article by Margo McDonough

Photo by Danielle Quigley

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Department of Plant and Soil Sciences adds Seyfferth to Staff

November 19, 2012 under CANR News

Angelia Seyfferth has joined the faculty in the Department of Plant and Soil Sciences in the University of Delaware’s College of Agriculture and Natural Resources (CANR).

Seyfferth previously conducted postdoctoral research at Stanford University under the Department of Environmental Earth System Science. She has a bachelor’s degree in environmental science from Towson University, and received a doctoral degree in soil and water sciences from the University of California, Riverside.

In addition to being an assistant professor in CANR, Seyfferth is also affiliated with the Delaware Environmental Institute (DENIN), which she says she looks forward to as it will open the door for interdisciplinary research opportunities, especially with regards to environmental issues.

“UD has started a strong focus on environmental issues with the creation of DENIN and the Critical Zone Observatory and it just seems like a really exciting time to be here, to be affiliated with the environmental movement that’s happening on campus,” said Seyfferth.

One of the areas that Seyfferth’s research focuses on is arsenic levels in rice, and she said that interdisciplinary collaboration can help inform this research. “I think you can learn a lot about a particular topic if you’re narrowly focused on it but to solve some of these big issues, you need to think trans-disciplinary. So if you think about the arsenic in rice issue, you have to understand what’s happening in terms of the soil chemistry but also the plant physiology and if you were just closed to one or the other, you may not understand how they interact.”

There is also a social aspect for communities–especially those in South and Southeast Asia–when it comes to rice that Seyfferth said can only be solved through interdisciplinary collaboration.

“Typically natural scientists and social scientists have little interaction.  One of the great things about DENIN is that natural scientists have the opportunity to interact with people on the social side,” said Seyfferth. She explained that in Cambodia, the word for “to eat” is the same as the word for “rice” and having outsiders come in and simply tell the residents to change their practices won’t work without understanding the social science aspect.

“So again, just like not any one scientific discovery is going to fix the problem, it’s not just one field, it’s going to be several different people coming together with different experience and expertise to solve some of these complex environmental issues,” said Seyfferth.

Seyfferth said that her research “focuses on understanding the processes that dictate contaminant and nutrient cycling in the rhizosphere and lead to uptake of contaminants by food crops.” Another part of her research is “looking at ways to minimize the amount of contaminants that are taken up by food crops.”

One such contaminant is arsenic.

As far as arsenic in rice, Seyfferth explained that rice is very susceptible to arsenic because of the way in which it is grown. Most soils contain arsenic, but when arsenic is present in soils that are aerated, the arsenic is bound to the solid soil particles and doesn’t move.

Rice, however, is mostly grown in flooded conditions.

“If a plant is going to take up arsenic, the arsenic needs to be in the soil solution,” said Seyfferth. “The process of flooding a soil sets up a whole different suite of biogeochemical conditions which allow the arsenic to be released from the solid and move into solution where the plant can take it up. So rice tends to accumulate more arsenic than other cereals because it’s mostly grown under flooded conditions.”

When it comes to the risk that arsenic in rice poses to Americans, Seyfferth said that the arsenic toxicity has to do with a variety of factors, among them is the concentration of arsenic in whatever a person may be ingesting, and the amount of tainted food and water ingested.

This is one of the reasons that Americans are at less of a risk than citizens of South and Southeast Asia. For one thing, the water quality standards are safer in the U.S. than they are in, for example, Bangladesh and Cambodia. Also, Americans do not depend on rice in their daily diet as much as those in Southeast Asia, where they eat rice 3 times a day, everyday.

That doesn’t mean that Americans should not be concerned, however. “I think it’s important to be concerned, to be aware of any chemical that you’re being exposed to,” said Seyfferth. “But the amount of rice that we tend to eat, typically in the U.S. is much lower. If we have it a couple times a week, it’s probably not going to have a huge impact.”

Seyfferth also notes that brown rice, while more nutritious than white rice, is also higher in arsenic concentration. “The act of polishing the rice to make it white removes the micronutrients that are located on the outer layer of the grain,” said Seyfferth. “So if you polish it, you’ve removed much of the arsenic but you’ve also removed many of the micronutrients that we actually need.”

Article by Adam Thomas

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CANR Summer Institute starts scholars on road to success

August 23, 2012 under CANR News

As the University of Delaware’s College of Agriculture and Natural Resources Summer Institute comes to a close, this year’s participants, Bianca Riddick and Walker Jones, are heading home having completed research projects and gotten a feel for the UD campus.

“I think it’s going to be bittersweet,” said Riddick. “I’m going to miss it when I’m ready to go home. It’s grown on me.”

The 10-week Summer Institute is designed for underrepresented populations of undergraduate students who have an interest in pursuing graduate degrees in the agricultural and natural resource sciences. It is intended to provide these students with an opportunity to learn about the varied and exciting opportunities available in graduate education at the college.

Bianca Riddick

Riddick, who will be a junior at Norfolk (Va.) State University as a pre-med student majoring in biology with a minor in chemistry, said that her time at the Summer Institute was instructive as she conducted research for the first time on a subject out of her normal area of study: rice.

“I never thought I’d be working with rice,” said Riddick. “I really don’t care too much for rice, but some people depend on rice so it’s good to contribute to the research of this disease.”

The disease in question is known as “rice blast” and Riddick studied the interaction between the rice blast fungus and a bacterium that has the potential to be a bio-control agent for the disease. Specifically, Riddick looked at a handful of fungal genes in rice blast to see how they react — if they turn on or off — to the bacterium in order to get a better idea of how the disease-causing agent is defending itself against the bio-control agent.

The reason behind looking for a bio-control solution to the rice blast problem is that it has the potential to be more cost efficient and environmentally friendly than applying pesticides.

Riddick is studying in the laboratory of Nicole Donofrio, who said that she has been amazed at how quickly Riddick picks things up, especially since this is her first time conducting research.

Donofrio, assistant professor in the Department of Plant and Soil Sciences, said of Riddick, “she is one of those people who just gets it. A lot of people, when they first start research, and this was the case with me too when I was an undergrad, have a pretty shallow learning curve. I had to make a lot of mistakes and Bianca is a rare student because she retains all of this information we’re throwing at her on the first try.”

Donofrio said that she has been so impressed with Riddick this year that she is going to ask her to come back next summer.

Riddick said that she has really enjoyed her time at the Summer Institute, calling it “a really good experience. It has everything laid out for you, you just have to come here and give your time. And I think that it’s a really good eye-opener.”

She also said that she has enjoyed the UDairy Creamery, with her favorite flavor being Cookies and Cream.

Walker Jones

Like Riddick, Jones also had to conduct research in an area outside of his wheelhouse.

As a senior at Virginia State University, Jones studies agricultural business and economics, but he spent the summer with Kent Messer helping him conduct a study on how beachgoers at Cape Henlopen and Rehoboth Beach would behave if there were offshore energy production providing renewable or lower energy costs but also affecting the aesthetics of the beach.

While conducting a study on the beach may sound like a summer job that is every undergraduate’s dream, Messer explained that Jones’ job was tougher than it sounds.

“This is actually really hard work. Going to the beach sounds really fun until you spend six days standing on the beach being told, ‘No, we will not participate in your study.’ And it’s 95 degrees, and you’re sweating and your relief is that you get to go hang out inside of a tent,” said Messer, associate professor in the Department of Applied Economics and Statistics.

Messer said that Jones was integral in getting the study conducted, as he conversed directly with state officials from the Delaware Department of Natural Resources and Environmental Control, getting the permission for the group to set up their tent at Cape Henlopen. Messer credited Jones with securing a “great spot” for the research project and said that it was a huge help to be able to give Jones such a high level of responsibility.

The research project involved having a computer simulation show participants images of wind turbines and oil drilling platforms as options for offshore energy. The participants were able to move the turbines or platforms closer or farther away from the beach, with the idea being that the closer the objects got, especially the wind turbines, the energy costs would be lower but the aesthetics of the beach would be affected.

Jones said that the group found that more people were open to the idea of having wind turbines present and closer to the shore, rather than oil platforms. “The (Gulf of Mexico) oil spill tragedy is still ringing true with some people and they don’t want that to happen again so when they see the picture of an oil platform they’d say, ‘No, I don’t like it,’” said Jones.

Jones said that he has enjoyed his time at UD, especially the fact that there are so many researchers on campus conducting a wide range of research in different departments.

He also said that he “really enjoyed how cooperative things went here, and how easily approachable the administration is around here.”

Tom Sims, CANR deputy dean and the T.A. Baker Professor of Plant and Soil Science, said that the Summer Institute was launched four years ago to “provide outstanding students such as Walker and Bianca with the opportunity to work with faculty mentors and learn more about graduate education in the agricultural and natural resource sciences.”

Sims continued that many of the 16 Summer Institute participants have “since entered graduate or professional schools both at UD and other top graduate programs. I’m sure that Walker’s exposure to the exciting new field of experimental economics and Bianca’s experiences in plant molecular biology have better prepared them for similar opportunities — we wish them well and look forward to continuing to work with similar dedicated students in the future.”

Article by Adam Thomas

Photos by Danielle Quigley and courtesy Kent Messer

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Tunisian Fulbright Scholar studying beneficial bacteria for legumes

May 29, 2012 under CANR News

At first glance, it wouldn’t seem like Delaware and the Sahara Desert have a lot in common. However, on closer inspection, the mid-Atlantic state and the arid regions of southern Tunisia in Africa are more similar than they first appear.

That is one reason why Mokhtar Rejili, a professor from the University of Gabes in Tunisia, is excited to be at the University of Delaware on a Fulbright Scholarship working with UD’s Janine Sherrier on the study of legumes native to his home country.

Of the similarities between the two seemingly disparate locations, Sherrier, a professor in the Department of Plant and Soil Sciences in UD’s College of Agriculture and Natural Resources, explained that Delaware has sandy soil and shoreline salt stress. “Our sandy soils dry out very rapidly and our crop plants can be subject to salt stress. There are also common stresses experienced by plants grown in the two locations, albeit to different levels of severity,” she said.

The scientists are collaborating on research to identify beneficial bacteria to help the plants grow more successfully under conditions of drought and salt stress. Rejili specifically studies legumes that grow in conditions of extreme drought and severe salt stress, and his Tunisian team identifies bacteria that interact with the plant roots growing on the outskirts of the Sahara.

Sherrier is recognized internationally as a scientific expert on bacterial interactions with legumes, and together, the two scientists are working on a research project that will help farmers in Tunisia and Delaware.

The scientists are conducting research that focuses specifically on the type of beneficial bacteria that associate with legume roots and provide nitrogen to the plant. Nitrogen is an essential nutrient for plant growth, and it is often provided to the plant by the application of chemical fertilizers or manure. This is costly for growers and contributes to environmental pollution.

The beneficial bacteria studied by the team can convert a small amount of the nitrogen that is naturally abundant in the Earth’s atmosphere into a form that can meet the nutritional needs of the plant. This reduces the cost of crop production for the grower and also protects the environment from damage caused by fertilizer runoff from agricultural fields.

“The plants form close relationships with the beneficial microbes. They develop a new organ on their roots for the bacteria to reside and provide the right environment and all the energy required for the bacteria to convert atmospheric nitrogen into fertilizer,” Sherrier said. “At a practical level, that means plants growing in soils without sufficient nitrogen can still have productive growth.”

Benefits to health and the environment

Rejili explained that this is especially important for extremely hot and dry areas, like southern Tunisia, where a chemical fertilizer would be of little help to the plants. Such fertilizers are often too expensive to even consider using and, worse, can be detrimental to human health.

“The fertilization of crops is limited to only the well-developed countries,” said Rejili, noting the high costs involved in producing fertilizer, only a small fraction of which is used by the plant. The remainder goes deep into the soil, where “it will contaminate the soil and the water, or it will evaporate into the atmosphere, leading to pollution,” he said, adding this poses “a big question to our health.”

Sherrier said that fertilizer use doesn’t pose a health risk just in Tunisia, it does so in America as well.

“The overuse of fertilizer impacts human health,” said Sherrier, explaining that a recent Environmental Protection Agency (EPA) survey of well water quality in Delaware’s southern counties showed that more than 50 percent of the wells had nitrogen contamination above the levels recommended for drinking water and required remediation.

Sherrier said that while Rejili is interested in helping out his home country, he is also concerned about improving crop production and health for Delawareans.

“People from Delaware love their lima beans, but the beneficial bacteria are not present at very high levels in our soils. Our growers add fertilizer to ensure a good yield. That’s expensive for them, and it’s not good for our environment,” said Sherrier, adding that Rejili has taken on a leadership role on one of her projects to identify beneficial bacteria from Delaware soils that could be added to the soil early in the growth season instead of chemical fertilizer.

Sherrier also explained that the damage to the environment is not just in the fertilizer application, it’s also in the way fertilizer is made. “There’s a huge energy cost associated with making fertilizer,” said Sherrier, explaining that the process requires high pressure and high temperatures, and uses 4 percent of the world’s natural gas supply annually.

“When you burn that natural gas, it releases carbon dioxide into the atmosphere,” she said, adding that there are additional environmental costs in transporting the fertilizer.

Inexpensive option

Besides the environmental and health considerations of cutting down on fertilizer use, the beneficial bacteria could also be an inexpensive option for growers, something that is of particular importance in developing countries.

“We would like to provide whatever help we can to allow the people of Tunisia to support their own food production,” Sherrier said. “Food security is a huge concern for any country. This inexpensive approach to food production protects their environment and helps provide the people with a basic level of security that every human being deserves.”

Providing an inexpensive and reliable food source for developing countries is not the only benefit of this research, however. Being able to grow legumes in areas that have harsh landscapes, like southern Tunisia, will enable the growth of forage crops in areas prone to desertification. This will allow livestock to graze in the area, and will help stabilize a sandy landscape that is prone to degradation from unforgiving winds.

“If you have a few plants that can survive in that area, they can protect soils and prevent the region from converting into desert. This will help preserve the land for food or forage production,” explained Sherrier.

Beneficial bacteria

Sherrier worked closely with the U.S. Department of Agriculture (USDA) and the Delaware Department of Natural Resources and Environmental Control (DNREC) to arrange for the team to study Tunisian plants in her Delaware laboratory. For some of the species, it is the first time that these legumes will be studied outside of Tunisia.

Rejili is evaluating the diversity of bacteria associated with these plants and performing experiments to determine which ones provide the most benefits. In a laboratory setting, the team is inoculating plants with individual strains of beneficial bacteria and evaluating the plant’s performance.

“The bacteria infect the plant root,” Sherrier said, “and when you talk about an infection, most people think, ‘Oh, no! You need to spray something to get rid of that.’ However, in undisturbed natural environments, the bacteria normally infect the plants, boosting their immune systems and helping the plants acquire essential nutrients. This is very similar to the benefits people gain from the bacteria which naturally reside in our digestive tract.”

Said Rejili of the plant interacting with the bacteria, “We can say they are beneficial interactions. So the plants give carbohydrates to bacteria and bacteria gives nitrogen to the plants. So there is an exchange.”

The two hope that when Rejili’s 10-month stay concludes, they can continue their collaboration. “This is a great starting point, and it’s really what the Fulbright progam is all about,” said Sherrier. “It’s helping to build bridges scientifically and culturally.”

Article by Adam Thomas

Photo by Danielle Quigley

This article can also be viewed on UDaily

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UD, DBI use advanced technology in genomic sequencing

May 22, 2012 under CANR News, Cooperative Extension

The Delaware Biotechnology Institute (DBI) at the University of Delaware has been equipped with a state-of-the-art Pacific Biosciences RS DNA sequencing machine to help researchers obtain genetic information, making UD one of the few universities in the country equipped with the advanced device. In fact, at the time of its installation, UD was the 25th site in the world to house such a machine.

The machine came to UD and DBI thanks to a $744,538 National Science Foundation (NSF) award and is stationed in the UD Sequencing and Genotyping Center, which is run by Bruce Kingham and provides genomic technology services for University research groups as well as outside investigators.

UD is in a unique spot with the machine because, as K. Eric Wommack, professor of environmental microbiology in the Department of Plant and Soil Sciences, explained, “Most of the places that have the Pacific Biosciences machine are large sequencing centers that sequence the human genome through massive amounts of sequencing, or they’re government labs. I believe we are one of the few research Universities without a medical school that has one of these instruments.”

Because of this, the sequencing machine will be used in unique ways, branching out into areas such as environmental and agricultural studies, with Wommack being one of the first UD professors to use the machine for research purposes.

Wommack was awarded a $200,000 NSF EAGER Collaborative Research grant focusing on exploratory application of single-molecule real time (SMRT) DNA sequencing in microbial ecology research.

The grant will focus on three areas of research. The first is in the area of single cell genomics, in which Wommack and his collaborator at the Bigelow Marine Laboratory in Maine will pull a single bacterial cell out of an environmental sample and sequence its genome.

The second has to do with characterizing the composition of a microbial community using a single gene, with the Pacific Biosciences machine enabling Wommack to look at changes in the sequence of a single gene in order to infer information about the species of microbes making up the microbial community as a whole.

The third application is what he calls “shotgun meta-genomics of viral communities,” which is the heart of his research. Explaining further, Wommack said, “The reason it is called ‘shotgun’ is that we literally are randomly sampling sequences from viruses in the environment.”

Piecing together genetic puzzles

Wommack said a problem with obtaining genetic sequence information is that the process takes a long time when in fact it needs to be as fast and accurate as weather predictions. “What if we could only measure temperature once a week? We really wouldn’t know a lot about how the climate and how weather works,” he said. “But of course, we can measure temperature in incredibly small scales of time. That’s where we need to get in the use of genetic data and environmental science and the Pacific Biosciences instrument gets us a little bit closer to that.”

The machines currently utilized at the center — while they each serve their own function — are slower than the new model, which Wommack said, “Allows you to run a lot of samples quickly.” They also provide shorter snippets of genetic sequence.

The current high-throughput DNA sequencers read anywhere from an average of 50 base pairs — that is, DNA “letters” — to 400 base pairs, while the Pacific Biosciences instrument can read anywhere from 1,000-12,000 base pairs.

Kingham said of the longer sequences, “Many times when you’re studying genomics, the length of the DNA sequence is everything, so the longer the DNA sequence read for each sample, the better.”

With the shorter sequences, Wommack explained, researchers have to take the little snippets and match them together, like piecing together a jigsaw puzzle. He compared putting together data on the old machines to solving a 1 million-piece puzzle, while putting together data on the new machine is like solving a 100-piece puzzle.

Kingham explained that another big advantage of the Pacific Biosciences machine is that researchers are able to monitor a single DNA molecule as it’s being replicated, as opposed to the other machines in the lab that rely on making copies of the DNA before it can be analyzed. “If you make a copy of something and then you make a copy of that copy, and then you make a copy of the copy of the copy, ultimately what you end up with is likely going to look somewhat different than what you started with,” said Kingham.  “The same thing can happen when you copy DNA.”

Kingham also said that he encouraged “anybody that’s involved in life sciences research to consider using that Pacific Biosciences sequencer because it’s so new, there’s so little known about how it can be utilized, and through the ability to analyze a single molecule of DNA, it has the possibility to change the face of genomics research.”

Without distinguished faculty at UD involved in genomics research, Kingham said, it may not have been possible to have obtained the machine. “This is a good representation of the prestige of genomics research at the University of Delaware,” he said. “Many of the scientists are internationally renowned in genomics research. Blake Meyers, Pam Green, Eric Wommack, Carl Schmidt, and others — these faculty members are internationally renowned in their respective fields of study.”

Kingham went on to say that the machine is “absolutely the cutting edge of DNA sequencing technologies, and UD is really fortunate to have it.”

About the UD Sequencing and Genotyping Center

The UD Sequencing and Genotyping Center is equipped with three DNA sequencing instruments — the Pacific Biosciences instrument, an Applied Biosystems Sanger sequencer, and the Illumina HiSeq 2000 genome sequencer.

While Kingham said he is thrilled about the new Pacific Biosciences machine, he is also quick to point out that each of the sequencers has its own relevant application area.

The Sanger machine, explained Kingham, “has been around for 40 years, and will probably be around for another 40 years. The advantage to that technology is it produces very high quality data. The disadvantage to it is that it can be very expensive to generate that data.”

The Illumina instrument, Kingham said, generates a large amount of data very inexpensively, but he added that the data might not be of as high a quality as that produced by the Sanger machine.

As for the Pacific Biosciences sequencer, the long length of the sequencing read, coupled with the ability to analyze a single molecule of DNA, cannot be matched by the other instruments.

For more information on the UD Sequencing and Genotyping Center visit the website.

Article by Adam Thomas

Photo by Danielle Quigley

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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

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Professors, students travel to UFLA; interns selected for collaborative work

April 24, 2012 under CANR News

Three professors and two graduate students from the University of Delaware spent spring break in Brazil, visiting the University Federal de Lavras (UFLA) campus, strengthening the academic and cultural bonds between the two universities and taking in the sites and sounds of the South American nation.

In addition, four UD College of Agriculture and Natural Resources (CANR) undergraduate students have been selected for an opportunity to develop international teaching modules in conjunction with professors and students at UFLA and UD, and to visit this University in 2013.

About the UFLA trip

During the spring break trip, the UD delegation spent its time meeting with faculty from UFLA, touring the facilities, teaching classes and taking trips to remote locations ranging from waterfalls to biodiesel factories. They were escorted by Eduardo Alves and Antonia dos Reis Figueira, both professors of plant pathology at UFLA.

Greg Shriver, assistant professor in CANR’s Department of Entomology and Wildlife Ecology, said he found it to be a very informative trip and found that much of the research being conducted by entomologists at UFLA is similar to research under way at UD.

Talking with Jùlio Louzada, the head of UFLA’s applied ecology department, Shriver said, “They actually have a forest fragmentation study going on in and around Lavras, which is a lot like the study we have going on in and around Newark.”

Shriver and Zach Ladin, a CANR doctoral student, were able to visit part of the Cerrado, a vast tropical savannah ecoregion near the UFLA campus where the study is taking place, and said that the two universities hope to collaborate on their studies regarding dung beetles.

Nicole Donofrio, assistant professor in the Department of Plant and Soil Sciences, said she was impressed by the campus, noting that “the academic buildings are gorgeous and equipped with an impressive array of new research equipment,” and added that the trip was crucial in providing strong connections between the two universities for the coming years.

“One of the goals was to make more connections and try to find additional links for people to have ‘sandwich students’ here in the next two years,” Donofrio said. Sandwich students refers to a program established between the universities in which UFLA doctoral students spend one year studying at UD that is “sandwiched” between their studies at UFLA.

Donofrio and Emily Alff, a CANR master’s student, taught a class on fungal transformation for the UFLA students. Alff said that being on the UFLA campus was a tremendous experience. “All the research they do is so applied,” she said. “It really makes you think about the bigger picture of research as a whole.” She added that the food and climate were perfect, saying, “Brazil is just a gorgeous country.”

Tom Powers, assistant professor of philosophy in the College of Arts and Sciences (CAS) and director of UD’s Center for Science, Ethics and Public Policy, said he was impressed by a UFLA practice in which they try to “leave nothing behind.”

Powers joined Donofrio and Alff on a visit to UFLA’s model biodiesel and bioethanol plant, located on the campus. “They use the water from the roof and the parking lot to run a lot of the processes,” he said, adding, “They use everything from, or have the potential to use everything from, fish guts to waste from sugar cane and castor beans. So, in terms of using all of these materials for the production of biofuels, it’s really astounding. And then what they don’t make into biodiesel they make into soap and everything else. They’re really trying to find some use for every byproduct in the production process.”

About the Brazil internships

Four CANR student interns have been chosen for an opportunity to conduct research and teach courses at UFLA.

The four interns who have been chosen for the project are:

  • Sarah Thorne, a junior;
  • Sara Laskowski, a junior;
  • Jacqueline Hoban, a freshman; and
  • Melanie Allen, a junior.

The internship will run from April 2012 through June 2013, with the interns supervised by UD faculty teams.

Hoban said she is looking forward to getting to travel to Brazil, and “excited about getting to work with a lot of interesting people and learning about a wide variety of research topics.” Hoban said that the internship “appealed to me not only because of the exciting travel opportunity, but also because it seemed like a really interesting way to apply the material that I have been studying in class.  The project gives me a different perspective on the subjects that I am interested in learning about. It also opens my mind to the educational aspect of my fields of study.”

Hoban added, “Everyone on the team seems like they have a lot of passion for their research and I cannot wait to work with them.”

The project is led by a faculty team from CANR and CAS and is intended to help build longstanding academic programs and research partnerships with UFLA that will enhance the international nature of curricula in areas of common interest, such as food security, bioenergy animal agriculture and biodiversity.

The project will also aim to stimulate creative thinking in the students who participate about how to develop innovative solutions to complex global agricultural and environmental problems.

There will be a curriculum enhancement portion of the internship, where students will assist faculty on both a part time and eventually a full time basis, and an experiential learning aspect, where the students will travel to Brazil for up to four weeks with UD faculty.

The interns will be responsible for developing a minimum of two teaching modules per course, and the modules will consist of PowerPoint presentations or other innovative learning methods that provide detailed information on the course topics developed by the interns and their faculty advisers.

This new research and teaching project is supported by the U.S. Department of Agriculture’s International Science and Education Program.

Article by Adam Thomas

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Prestigious travel grants allow UD students to attend plant biology conference

March 30, 2012 under CANR News

Harsh Bais, assistant professor in the University of Delaware Department of Plant and Soil Sciences, has chosen his research team well. Two members of his group, postdoctoral researcher Venkatachalam Lakshmanan and graduate student Emily Alff, have received travel grants from the American Society of Plant Biologists (ASPB), which will enable them to attend the society’s annual meeting this summer in Austin, Texas.

According to Bais, the number of ASPB travel grants is limited to 20 for postdocs and 30 for graduate students worldwide.

Alff received the ASPB travel grant for her project that explores the role of rhizobacteria in rice growth promotion and defense against the fungus Magnaporthe oryzae, commonly known as rice blast.

Her research examines the natural relationships between rice plants and the microbial communities that inhabit the rhizosphere, the area surrounding their root systems. Secretions from the root system are rich in nutrients, which sustain microbial communities that can be detrimental or beneficial to the plant.

Rice blast can cause devastating crop losses, but Alff’s research has demonstrated that certain bacteria can significantly decrease the effects of rice blast and improve plant growth. The goal of the project is to provide a basis for inoculating seeds with beneficial microbes, which is cost-effective for farmers and more environmentally sound than fungicides.

Lakshmanan’s research was also selected for oral presentation in a “mini-symposium” on plant-microbe interactions as part of the conference. He studies microbe-associated molecular patterns, or MAMPs, which are responsible for triggering a plant’s immune response if it is attacked by a pathogen. This signaling process is well understood in response to foliar pathogens; however, the role of MAMPs in response to the belowground microbial community is largely unknown.

Lakshmanan’s project indicates that certain beneficial rhizobacteria are able to block MAMPs signaling and subdue an immune response from the plant, allowing them to colonize the plant’s root system. The bacteria are beneficial because they subsequently activate the plant’s immune response if it is attacked by another pathogen. Lakshmanan’s research is expected to expand the current understanding of intra-plant signaling and its relationship with microbial communities.

Awards for current research in the field, which affects many of today’s top issues, will be presented at the Plant Biology conference. Alff is eager to see how it will play out.

“It is extremely important to me to see the impact that plant biology research is making towards the vital issues of food security and safety, climate change, bioenergy, and medicine,” she said.

Lakshmanan sees the plant biology symposium as “a unique opportunity to network and receive feedback from peers.” At the conference, Alff and Lakshmanan will present and discuss their research with plant biology faculty, postdocs and students from around the country.

Alff says, “This meeting will help in my transition from a graduate student to a professional scientist. Receiving feedback from the plant biology community will help in preparation for my thesis defense and eventual job interviews.”

The research conducted by Alff and Lakshmanan in Bais’ lab is supported by grants from the National Science Foundation and the Delaware EPSCoR program.

Article by Jacob Crum

Photo of Emily Alff by Kathy F. Atkinson

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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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UD’s Wommack part of $25 million USDA food supply safety study

February 21, 2012 under CANR News

K. Eric Wommack, professor of environmental microbiology in the Department of Plant and Soil Sciences at the University of Delaware, is part of a five-year, $25 million U.S. Department of Agriculture (USDA) study aimed at preventing potentially fatal illnesses linked to Shiga toxin-producing E. coli bacteria (STEC) in the nation’s food supply.

STEC poses a serious threat to the food supply, resulting in more than 265,000 infections in the United States each year.

The coast-to-coast study includes a team of 48 investigators from multiple universities and government agencies, with the University of Nebraska and Kansas State University as the lead institutions.

Wommack became involved with the project after serving on a USDA grant review panel with Jim Keen, the lead project director from the University of Nebraska, who had been studying STEC for a number of years and was putting together the project proposal.  “It was really just good fortune on my part to be lucky enough to be involved with the group,” said Wommack, adding that he has not previously worked with STEC but can potentially bring a new angle to the research through his experience in microbial ecology.

As a microbial ecologist, Wommack said he is “interested in all the microbes that make up communities of microbes.” He equated this to an environmental ecologist, only instead of looking at “all the plant species within the make-up of the forest or the grassland, I look at all the microbes that comprise a microbial community.”

For this study, Wommack will examine the microbial communities that form around STEC to see if there is a pattern that scientists can pinpoint. This would allow the researchers to trace non-toxic levels of STEC by determining the kinds of microbial communities where it is most likely to occur.

“It is difficult to detect STEC when it is at the non-poisonous levels, but it is still there and so my work may show that there are other microbes that just happen to occur alongside STEC but are a whole lot easier to find. It is not like (STEC) is the only bacteria in a cow, so we are interested in looking at the larger communities that surround the pathogenic organisms.”

Wommack also will try to understand the ecology of STEC on a fundamental level.  “Although it is an organism that is an awful pathogen and kills people,” Wommack explained, “it is also a microbe that is out there and it has to live in whatever environment it is found in, and so most everything we know about STEC is when it is making people sick. We don’t really know much about it other than that — meaning its place in the ecology of microbial communities.”

Wommack said he is excited to get started on this research project, anticipating that he may begin work as soon as March. “It is hard to argue against knowing more,” he said. “Knowing and understanding more about the biology and the ecology of the organism will ultimately help us to control its incidence in the food supply.”

About Prof. Wommack

K. Eric Wommack is a professor in UD’s Department of Plant and Soil Sciences in the College of Agriculture and Natural Resources.

He also has appointments in the Department of Biological Sciences in the College of Arts and Sciences and in the marine biology and biochemistry program in the College of Earth, Ocean, and Environment. His laboratory is based in the Delaware Biotechnology Institute.

Wommack received a doctorate in marine estuarine environmental sciences from the University of Maryland, a master’s degree in physiology from the University of St. Andrews in Scotland and a bachelor’s degree in economics from Emory University in Atlanta.

He is a member of the American Society for Microbiology, the American Society of Limnology and Oceanography and the International Society for Microbial Ecology.

Article by Adam Thomas

Photo by Evan Krape

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