As cities and suburbs have sprawled across the United States, they have not only provided new housing and developments but also given rise to what researchers are calling the American residential macrosystem, a new biome encompassing urban, suburban and extra-urban lands with biological, geophysical and social components that interact with one another.

Using six cities from across the United States, the University of Delaware’s Tara Trammell is part of a team of researchers from multiple universities looking at factors that contribute to stability and change in the American residential macrosystem as well as the future ecological implications at the ecosystem, city, regional and continental scales.

The research is funded by the National Science Foundation (NSF) Macrosystems Biology Program and builds off prior work that was funded by NSF in 2012. The research includes study sites in Boston, Baltimore, Miami, Minneapolis-St. Paul, Phoenix and Los Angeles.

Trammell, the John Bartram Assistant Professor of Urban Forestry in the Department of Plant and Soil Sciences in UD’s College of Agriculture and Natural Resources, conducted her part of the project in Los Angeles in 2012 and will once again return to the city.

She said the original project looked at the ecological homogenization of America by researching residential lawns across those six cities, which are in different ecological biomes and climates, to see how similar the residential ecosystems were becoming based on people’s preferences and behaviors.

The research hypothesis was that the residential ecosystems and landscapes across the continent are more similar than the native ecosystems that they replaced, which can lead to altered ecosystem structure and function.

“The original project was a collaboration between social scientists looking at the social drivers of the American residential macrosystem and ecologists studying the ecological impacts of yard management. We found evidence for ecological homogenization in plant communities, soils, and nutrient pools, yet at the same time yard management may or may not be the same,” said Trammell.

This project will examine what factors, such as social drivers, are contributing to the stabilization or to changes of the residential ecosystems.

“There is an interaction between biophysical drivers and social drivers together effecting the homogenization. We’re trying to understand what factors are contributing to changes in residential systems and what factors contribute to stabilizing them,” said Trammell.

Some of these stabilizing factors include commercial drivers and perceived social norms or values, while agents for change include planting more wildlife supporting plants, using less fertilizer or utilizing xeriscaping — low water landscaping that is nearly devoid of plants.

Social factors that contribute to the changes or stabilization in the system include how much time people put into their lawns which can be dictated by life stage and socioeconomics.

“It’s not just the amount of resources you can put into the yard but your time. When I was in LA conducting homeowner interviews, several people who recently retired had plans for their yard. They were finally going to have time for landscaping versus the people who may have been working full-time with families,” said Trammell.

In addition to life stage and economic considerations, there are top down regulations that need to be taken into account as well. In Los Angeles, for example, with water use and water availability issues, regulations come into play that change people’s behavior.

The research will look at the ecological implications for these potential changes and stabilizations, focusing on how management influences hydrology, nutrient cycling and biodiversity.

“People are instituting hydrologic efficient aspects in their lawns, such as rain gardens or xeriscaping in the arid climates. How are these changes in yard management effecting ecological function? We’re looking to see if nutrient use efficiency, water use efficiency and wildlife supporting management behaviors in your yard effect biodiversity at different trophic levels and nutrient retention or runoff,” said Trammell.

The first project measured plant communities, soils and microclimate, while this time around the researchers are going to include higher trophic levels and water and energy balance.

“We’re adding insect and bird biodiversity to the study to see if yards with greater plant biodiversity support higher trophic levels,” said Trammell.

Article by Adam Thomas

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On first glance, Yakushima Island in Japan and Dorchester County, Maryland, wouldn’t appear to have a lot in common, but a closer ecological look reveals one stark similarity: both are home to populations of sika deer.

A new paper by the University of Delaware’s Jake Bowman and David Kalb of the Virginia Department of Game and Inland Fisheries looks at the history behind the rise of sika deer populations in Dorchester County over the past 100 years.

The paper was published in the journal Biological Invasions and also examines impacts sika deer have had on the native white-tailed deer populations in an attempt to provide information that could lead to better management of the species.

Bowman, chair of the Department of Entomology and Wildlife Ecology in UD’s College of Agriculture and Natural Resources, said that the paper was part of a bigger project looking at whether there was a competitive exclusion between white-tailed deer and sika deer.

“There’s large sections of Dorchester County that have almost no white-tails but very high sika deer numbers, and it seems like the sika deer are spreading, so the question becomes, are they going to outcompete white-tails, which is our native deer,” said Bowman.

Sika history

Sika deer first came to the United States in 1916 and the initial population of four or five individuals has grown to an estimated 12,000 today.

Bowman said that there has been some genetic work that suggests the sika deer originated on Yakushima Island in Japan though the deer that eventually made their way to the United States did so after a brief stopover in the United Kingdom. The deer were brought to the UK by the eleventh Duke of Bedford.

The sika deer were introduced to Maryland in the early 1900s when Clement Henry released five or six deer on James Island.

While the deer originated in Japan, they are now more populous in Maryland.

“There’s more sika deer here than on Yakushima Island and they’re a protected species in Japan so they can’t be harvested at all,” said Bowman.

The sika deer eventually escaped James Island and the population grew over time.

“They were expanding their population at a time when there were very little white-tails in that area. It was during the time when there was over-exploitation of white-tails and their numbers were really low. One theory is that the sika deer established themselves before the white-tail populations rebounded and prevented them from re-occupying some areas,” said Bowman.

In addition to possibly competing with other herbivores and pushing white-tailed deer out of their natural habitats, sika deer can also cause crop damage.

“There are complaints in Dorchester County about crop damage from them but the bigger concern from my perspective is ecologically. They’re not supposed to be here and if they are competing with white-tails, that’s a problem,” said Bowman. “What I saw when we did some population estimation work several years back before this project, the white-tail numbers were high in some areas and so were the sika deer numbers. So you compounded crop damage. You almost doubled the amount of deer on the landscape.”

The differences between white-tailed deer and sika deer are mostly digestive, as sika are more grazers — able to eat a wider array of food than the white-tailed deer, who have a narrower range of things they can eat, which Bowman said makes them ripe for competition.

This ability to eat a wider array of foods is apparent in the sika deer’s range of habitats. In Maryland, they are primarily found in wetland areas, while on Yakushima Island, they are found in the mountains.

“I think it could be because they can exploit some of those salt water plants that the white-tails can’t eat. That might be why they’re using those habitats more, whereas white-tails only use those habitats for bedding areas, they don’t use them for foraging. The sika may have expanded into some of those and that might be why they have such a stronghold in the area,” said Bowman.

The population in Maryland is the only free range population of sika deer in the United States that people are allowed to hunt and because of this, Bowman said that the Maryland Department of Natural Resources wants to maintain the populations of the deer but limit their spread.

“This is a perfect example of a biological invasion where we’re not going to get rid of the species because of people — there’s an industry out there that protects them and doesn’t want them to go away, and you see it in a lot of species. Catfish in the [Chesapeake] bay, for instance. They’re not supposed to be there but there’s a fishing industry for them now so we’re not going to try to get rid of them. We’re just going to try to reduce their numbers,” said Bowman.

In addition to the help from Maryland Department of Natural Resources, Bowman said that they would not be able to do their research without the help and support from the private land owners.

Article by Adam Thomas

Video by Jeff Chase

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University of Delaware undergraduate student Blair Schneider spent time in Brazil earlier this year getting samples from chickens to help with research looking to see if there is something genetically that allows the Brazilian birds to better deal with heat stress than American broiler chickens.

The research is being led at UD by Carl Schmidt, professor and genome scientist in the Department of Animal and Food Sciences in the College of Agriculture and Natural Resources, and is part of a five-year, $4.7 million National Institute of Food and Agriculture (NIFA) climate change grant for a project titled “Adapting Chicken Production to Climate Change Through Breeding,” which includes Iowa State University and North Carolina State University, as well.

With the researchers having previously sampled birds in Tanzania, Uganda, Kenya and Rwanda, Schneider, a senior majoring in biological sciences in the College of Arts and Sciences, said that the group wanted to look at South American chickens along the same equatorial line to see if there were any similarities with their African counterparts.

“We took blood samples and we’re going to get the genome sequenced to see what genes overlap between the African birds and the South American birds. We would hypothesize these [overlapping genes] are due to heat and heat stress or heat acclimation,” said Schneider.

If the researchers can identify those overlapping genes, they might be able to potentially breed beneficial genes into the modern broiler line in the face of heat waves.

To collect their samples, the researchers were guided by Matheus Reis, a postdoc at Sao Paulo State University (UNESP) in Jaboticabal, Brazil, who also spent a year at UD. Reis helped the researchers collect samples and connected them with a local farmer named Mário Irineu Salviato.

The farm at which Salviato worked had 150 different breeds of chicken and the researchers took 200 blood samples from a variety of different breeds, such as ones known as Brazilian Musicians because of how much they sing.

In addition to collecting the samples, Schneider said that she enjoyed being able to experience the Brazilian culture.

“Even at the times when I wasn’t collecting, I felt like I was learning so much. We visited UNESP, as well, and I was able to give a presentation there and then some of the students there gave presentations, and so it was a nice sharing of projects and scientific discussion,” said Schneider.

Schneider said that she enjoys doing genetics work because she likes to understand how things work down to their most basic level.

“My mind is down to the gene level. That’s why I wanted to study genetics but when I entered this lab, Dr. Schmidt made me go through the entire process of collecting the samples as well as analyzing the data and so I have an immense appreciation for the entire process,” said Schneider. “Anyone could just take a tissue from a sample and extract it but you get a new appreciation collecting it yourself.”

Now a senior, Schneider is getting ready to go to graduate school and said that she is interested in the genetics behind the differentiation of stem cells.

“But I’m willing to change. I’m flexible. If I can find an interest in something, it’s very easy for me to become passionate about it,” said Schneider.

Article by Adam Thomas

Illustrations by Jeff Chase

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To best understand landscapes and how different ecosystems interact with one another, sometimes it’s necessary to take a bird’s-eye view.

It was with that in mind that the University of Delaware’s Jeff Buler took students from his landscape ecology class up in a hot air balloon, so they could appreciate the inner workings of a landscape from the slow-moving confines of a hot air balloon basket.

“The purpose of the balloon trip was to give these students who are in the landscape ecology class a real-life landscape perspective. I thought the best way to provide that is to go up in a hot air balloon,” said Buler, associate professor in the Department of Entomology and Wildlife Ecology.

While there are other ways for the students to see a landscape from an aerial view — such as from a plane or via an aerial photograph or satellite imagery — Buler said that the finer details can be lost.

“When we were a mile up, you would look down and you could distinguish forest patches from agricultural fields. We could even see the Delaware Bay and the Susquehanna River and the skyline of Philadelphia from that height, so we got a really broad perspective,” said Buler. “As we came down to just maybe 100 feet above the ground, you get this sort of zooming in on the landscape as you descend, which reveals more and more detail as you come down.”

Among the interesting features the class was able to see were fields that had been plowed by tractors and those had been plowed by horses.

“Most of the farms were Amish farms that we’d fly over. We flew so low that we could actually tell they had been plowed by horses because you’d see the hoof marks in the fields, which of course you couldn’t see if you were higher up,” said Buler.

One of the things Buler wanted the students to get out of the trip was to be able to identify different landscape features, such as patches and edges and corridors, terms they talk about in class to characterize the landscape.

This being Buler’s second time taking a class up in a hot air balloon (a previous trip was made in the spring of 2014) he said that it was interesting to see how the landscape the class viewed this time differed from the landscape seen on the previous trip.

“It was a much more agricultural landscape than the other, which was more mixed and showed more of a gradient from rural to urban,” said Buler.

In the highly developed agricultural landscape, the students were able to see the connectivity of the environment, getting a nice view of natural features such as streams and riparian corridors along those streams that play an integral role in water quality within a watershed.

“Something that we talked a lot about in the course was how the water quality at one location is affected by inputs of pollution and other processes that are happening further upstream,” said Buler. “In this landscape, we were able to see streams that had nice intact riparian forest buffers but also other places where the farmers had cleared right up to the edge of the stream. It was a nice contrast to the last trip in that the students could better see how the stream networks were connected and where there were breaks in the riparian buffers that could be places where pollution could infiltrate.”

Buler said that going up in the hot air balloon reinforces lessons that the undergraduate and graduate students learn in his class, specifically about how diverse landscapes throughout space and time are of the upmost importance.

The class is also focused on managing habitat for wildlife, which has traditionally been done on a parcel by parcel basis, such as a piece of public land that is managed to create habitat for the species without consideration of how the larger landscape might affect what’s going on in that area.

“The class is designed to get students to think more broadly and recognize that the broader landscape is important. It’s important to think about how energy flows through the landscape, and to realize, especially from a wildlife perspective, that it is important to maintain connectivity among habitat patches,” said Buler. “You might be able to produce a very nice suitable habitat but you simply might not have the wildlife species there that you’re interested in because they can’t get there. There might be some barrier that prevents them from physically moving to that location. As we fragment landscapes more and more, it’s becoming a lot harder for wildlife to disperse through the landscape to be able to find suitable habitat.”

Article by Adam Thomas

Photos by Evan Krape

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The University of Delaware’s K. Eric Wommack, deputy dean in the College of Agriculture and Natural Resources, will lead a research team from four universities that has received a $6 million grant to probe how viruses impact microbes critical to our lives, from producing oxygen to growing food.

Also, UD’s Kelvin Lee, Gore Professor of Chemical and Biomolecular Engineering, is a co-investigator on a $6.1 million research project, led by Clemson University, aimed at lowering drug manufacturing costs.

The two four-year projects were announced by the National Science Foundation’s Established Program to Stimulate Competitive Research (EPSCoR) on Wednesday, Aug. 2. They are among eight projects across the United State, totaling $41.7 million, that aim to build U.S. research capacity in understanding the relationship in organisms between their genes and their physical characteristics. Uncovering this genotype-to-phenotype relationship holds potential for improved crop yields, better prediction of human disease risk and new drug therapies.

“Over the past several decades, scientists and engineers have made massive strides in decoding, amassing and storing genomic data,” said Denise Barnes, NSF EPSCoR head. “But understanding how genomics influence phenotype remains one of the more profound challenges in science. These awards lay the groundwork for closing some of the biggest gaps in biological knowledge and developing interdisciplinary teams needed to address the challenges.”

“The University of Delaware’s deep involvement in two EPSCoR grants underscores the world-class leadership and bold ideas of our faculty, as well as the powerful role of interdisciplinary collaboration for society’s behalf,” said Charlie Riordan, vice president of research, scholarship and innovation. “We congratulate Eric and Kelvin and look forward to the new technologies their teams will advance.”

A nano-lab for observing viruses and cells

In water and soil to the human gut, you’ll find single-celled microbes — and viruses right alongside them. A virus will infect a microbe, hijack its machinery and begin replicating, eventually killing the host. But how these processes work within complex microbial communities is still largely a mystery.

The multi-university collaboration that UD’s Wommack is leading will develop new technology to enable scientists to examine — in a droplet of water smaller than mist — how a single virus and a single microbial cell interact.

“Imagine doing a classic microbiology experiment with test tubes and culture plates. Our research would take all of those test tubes and cultures and reduce them down to a tiny droplet 100 times smaller than the diameter of a human hair,” says Wommack, who is an expert in environmental microbiology.

Operating under the principle that oil and water don’t mix, the interdisciplinary team will create devices the size of a microscope slide, equipped with tiny incubation chambers filled with oil, to isolate individual droplets of water injected with a syringe. Molds for these microfluidic devices will be fabricated in UD’s state-of-the-art Nanofabrication Facility for collaborators David Dunigan and Jim Van Etten at the University of Nebraska-Lincoln, Grieg Steward and Kyle Edwards at the University of Hawaii-Manoa, and Marcia Marston and Koty Sharp at Roger Williams University in Rhode Island.

“A big aim of our project is to democratize the microfluidics technology we develop so that the average lab can run these experiments,” Jason Gleghorn, assistant professor of biomedical engineering at UD, says. “It’s about making new tools and resources available to the broader scientific community.”

The research team also will create the Viral Informatics Resource for Genome Organization (VIRGO).

“We have troves of genomic data on viruses,” Wommack says. “What’s limiting our work is that we don’t know the connections between the genes and what the viruses do biologically. How quickly do viruses infect a host? How long do they take to reproduce? What happens to the infected cell? Once we have that information in VIRGO, we can look at a viral community and make inferences about how unknown viral populations will behave.”

A focus on environmental microbes

Collaborators in Nebraska, Hawaii and Rhode Island will focus on viruses that infect phytoplankton — microscopic organisms that live in the salty ocean to freshwater lakes and conduct photosynthesis.

Phytoplankton serve as big links in food chains and produce more than half the oxygen on Earth. They, along with other microbes, process as much as 70 percent of the carbon going through ecosystems, according to Wommack.

Meanwhile, researchers at UD will focus on viruses that attack microbes important to the nitrogen cycle.

They have a collection of symbiotic bacteria, called Bradyrhizobia, that provide nitrogen to soybean — fueling plant growth without extra fertilizers. Soybean feeds some 2 billion people globally, and more of it will be needed to feed a world population expected to hit 9 billion by 2050.

“We can’t simply fertilize our way to greater agricultural productivity,” Wommack says. “But if we can find a way to improve the plant’s innate nutrition system through research we’re doing now, we may be able to get a plant to do what it already does, a lot better.”

Wommack also has teamed up with Rob Ferrell, science teacher in the Appoquinimink School District, to translate the research into life science and earth science curriculum activities for middle school students.

Other UD members of the project include Barbra Ferrell, research associate; Jeffry Fuhrmann, professor of plant and soil sciences; Jason Gleghorn, assistant professor of biomedical engineering; Shawn Polson, associate professor of computer and information sciences; and Jaysheel Bhavsar, bioinformatics programmer.

Clemson collaboration to boost biopharmaceutical manufacturing

The EPSCoR project at Clemson University seeks better ways to engineer Chinese hamster ovary cells, which are used to manufacture more than half of biopharmaceuticals. Joining co-investigator Kelvin Lee on the project will be Cathy Wu, Edward G. Jefferson Chair of Bioinformatics and Computational Biology at UD.

Products from these cells are used in drugs to treat Crohn’s disease, severe anemia, breast cancer and multiple sclerosis, and represent more than $70 billion in sales each year, according to a Clemson news release.

Lee, who directs the National Institute for Innovation in Manufacturing Biopharmaceuticals (NIIMBL), said the EPSCoR project would help address challenges in making these medicines more widely available.

NIIMBL, announced in December 2016 at UD and launched in March 2017, was established with a $70 million grant from the National Institute of Standards and Technology in the U.S. Department of Commerce and with support from more than 150 collaborators.

Article by Tracey Bryant

Photos by Kathy Atkinson and Wenbo Fan

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To help plants better fend off insect pests, researchers are considering arming them with stones.

The University of Delaware’s Ivan Hiltpold and researchers from the Hawkesbury Institute for the Environment at Western Sydney University in Australia are examining the addition of silicon to the soil in which plants are grown to help strengthen plants against potential predators.

The research was published recently in the journal Soil Biology and Biochemistry and was funded by Sugar Research Australia. Adam Frew, currently a postdoctoral research fellow at the Charles Sturt University in Australia, is the lead author on the paper.

Hiltpold, assistant professor of entomology and wildlife ecology in UD’s College of Agriculture and Natural Resources, said the basis of the project was to assess the impact of arbuscular mycorrhizal fungi on a plant’s nutritional quality and also on root pests, using sugar cane and root-feeding insects, primarily cane grubs—the voracious larvae of the cane beetle.

“This research demonstrated a cascading effect,” said Hiltpold. “We have silicon and other plant nutrients in the soil, we have the fungi that is interacting with the plant and metabolites, and all that plant chemistry has an impact on insect development.”

Silicon is the world’s second most abundant element after oxygen in the Earth’s crust, but because it is in a stone or mineral form, it is not readily available for use by plants.

By amending the soil with silica, a form of silicon that plants can easily take up, the researchers helped the plants build up tiny particles called phytoliths, or “plant stones,” to defend against herbivorous insects and possibly rodents.

“The plant builds up these sorts of stones in its tissues, which will reduce the digestibility of the plant material because digesting stones is not very easy,” said Hiltpold. “Also, these stones wear the mouth parts of insects and possibly rodents. If your teeth are not really cutting any more, then you cannot eat as much as you could. All of that added together will reduce the impact of herbivory on the plant.”

In experiments with two sugarcane varieties grown in a greenhouse, root-feeding insects, primarily the cane grub, fed on the plants. The immune function of the insects was assessed by measuring their immune response to entomopathogenic nematodes—small organisms that kill insects in the soil—while insect growth and root consumption were assessed in a feeding trial.

The researchers found that high levels of silicon concentrations decreased insect growth and root consumption, the latter by 71 percent.

Because the silicon doesn’t affect grazing livestock, Hiltpold said that it also will not affect humans when, for example, a person consumes boiled carrots or sweet corn.

Hiltpold said they chose the cane grub for their study because it is a major pest in Australia.

“Sugar cane is a big industry in Australia, and these larvae are really causing a lot of damage to it. These grubs can be pretty big—their diameter can be as big as my thumb,” Hiltpold said. “As soil pests, they are really hard to control because they are hard to reach with insecticides and they are hard to monitor. We don’t really know where they are before we see the damage on the plant, and then usually it’s too late. Having options to control them is always good.”

The option of using silicon to naturally strengthen the plant’s defenses against the cane grub would be both environmentally friendly and economically attractive to growers, as they would not have to spray as much to protect their crops.

“The idea of amending crops with silicon in general is that, OK, we have this element that is naturally present. The only thing is that it’s not bio-available so it cannot be taken up by the plant as is, but if we add a little bit of bioavailable silicon to the field, then it boosts the plant’s biomass,” said Hiltpold. “The plant productivity is increased and also the plant defenses are increased because the silicon accumulates in the tissue above and below ground and helps the plants to cope with insect as well as mammal herbivory.”

Hiltpold said this research could be applicable to other types of plants besides sugarcane.

He also said that in addition to the plants’ interaction with the silicon, the fungi had a surprising impact on the insects.

“We don’t exactly know if it’s via the plant or directly from the exposure to the fungi, but the insect immune system was triggered when the plants were treated with the fungi,” said Hiltpold. “That could be useful in an integrated management view because triggering an immune system if there is no invader, no pathogen exposure, might have a cost on the growth or performance of the insect, so that will eventually have a beneficial impact on the plant because the insect is doing less well and doing less damage. I think that was an interesting finding that was never demonstrated before.”

Article by Adam Thomas

Illustration by Jeff Chase

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When it comes to advancing nutrient management planning for croplands across the United States, it is important to evaluate phosphorus indices to ensure accurate phosphorus loss risk assessment.

Until recently, however, most of these phosphorus index assessments have focused on the risks of phosphorus losses in surface runoff while inadequately taking into account the critical role of subsurface phosphorus losses.

This is particularly important in areas such as the Atlantic Coastal Plain, where subsurface flow is the predominant pathway of phosphorus transport from artificially drained agroecosystems — cropland that uses artificial drainage to lower water tables.

A new paper published in the Journal of Environmental Quality by researchers from the University of Delaware and other contributing institutions explores methods to evaluate the subsurface phosphorus risk routines of five phosphorus indices from Delaware, Maryland, Virginia and North Carolina using available water quality and soil datasets.

The research was funded in part by a United States Department of Agriculture (USDA) Natural Resources Conservation Service Conservation Innovation Grant.

Amy Shober, associate professor in the Department of Plant and Soil Sciences and a Cooperative Extension specialist, is the lead author on the paper, which represents some of the work done by Kathryn Turner, who worked in Shober’s lab and graduated from UD in 2016.

Co-authors include Scott Andres, hydrogeologist and senior scientist with the Delaware Geological Survey, Anthony Buda, U.S. Department of Agriculture, Thomas Sims, a retired UD faculty member and former deputy dean of the College of Agriculture and Natural Resources, Nicole Fiorellino, Chesapeake College, and Joshua McGrath, University of Kentucky.

Atlantic Coastal Plain

Shober said that some cropland on the Atlantic Coastal Plain must be artificially drained to lower the water table in order to avoid having water within the root zone of plants or standing water in their fields, which would disrupt farmers’ ability to use equipment and plant successful crops.

Shober said that today’s farmers are dealing with what is known as “legacy phosphorus,” phosphorus that is left over from past manure applications and that continues to contribute to water quality issues.

Using phosphorus indices, farmers and land managers can identify areas in the landscape where phosphorus sources overlap with the ways in which water moves phosphorus through the soils.

There have been a lot of studies evaluating the risk of phosphorus transport, such as erosion and surface runoff, because these losses are easily seen. Fewer studies have been conducted on the contributions of subsurface phosphorus to drainage waters, which are harder to track because they occur below ground and there are fewer tools to study these losses.

“You can collect runoff at the end of the field and know what came over that land surface,” said Shober. “It’s harder to identify where water moving through the ditch network originated. Water draining from the fields occurs underground, and the discharges from multiple fields mix as water moves through the ditch network. Not to mention that rainfall that is directly deposited to the ditch — and even overland flow — can also contribute to ditch flow.”

Soil data

To better study the subsurface phosphorus sources and transport, the researchers started looking at soil data to determine if the previously existing phosphorus index models were able to accurately predict subsurface phosphorus sources and transport. They found that the pre-existing hydrologic models to evaluate subsurface phosphorus were inadequate when it came to evaluating flat, artificially drained areas like those found in the Mid-Atlantic Coastal Plain.

For flat landscapes, the hydrologic models didn’t work because they need slope and are based on topography. Because the Mid-Atlantic Coastal Plain doesn’t have a lot of surface runoff but instead has a lot of subsurface runoff, the models were calculating for problems for which the model was not designed.

“There aren’t a lot of studies, especially in our region where it’s flat and there is a lot of ditch drainage, so we can’t calibrate and verify our phosphorus indices for subsurface phosphorus losses,” said Shober. “We started looking to see if we could use soil data to determine if we were going in the right direction. If we were really seeing high phosphorus risk in places where this index is identifying high subsurface losses.”

Shober said that the researchers were able to conduct this study using previously collected soils, which can be stored for long periods of time and still contain measurable phosphorus.

Subsurface phosphorus index

Using a library of soil cores that the authors had collected at different depths from all over the Delmarva Peninsula and using data collected by Sims and Andres, the researchers calculated the risk for subsurface phosphorus loss using five phosphorus indices. They looked at the phosphorus index scores without taking into account any manure application, only concerning themselves with contributions of the legacy phosphorus.

“For our index, we eliminated the things that we weren’t interested in looking at so we ultimately got a score that we consider was just for this subsurface risk,” said Shober. “We wanted to say, ‘OK, what is the inherent risk of subsurface losses of phosphorus that was in the soil?’”

Once they got those numbers, they looked at the water-extractable phosphorus at the depth of the seasonal high water table and correlated the data to see the relationship.

To find the water-extractable phosphorus, the researchers took a small amount soil and a little bit of de-ionized water and shook them for an hour and measured how much phosphorus came out of the soil.

“If the phosphorus index subsurface score was low and the water-extractable phosphorus in the soil at the depth of the water table was low, we would expect a low risk of subsurface phosphorus losses. So, ultimately, we wanted to see scores increasing either linearly or exponentially as soil water extractable phosphorus increased – the higher the risk score, the higher the water-extractable phosphorus level should be,” said Shober.

The calculation using water extractable phosphorus concentrations at depths corresponding with the seasonal high water table could serve as a realistic proxy for subsurface losses in ditch drainage and as a valuable metric that offers interim insight into the directionality of subsurface phosphorus risk scores when water quality data are inaccessible.

This will all help to improve monitoring and modeling of subsurface phosphorus losses and enhance the rigor of phosphorus index appraisals, Shober said, adding, “We’re hoping that this is something that people can do to move forward with our understanding of subsurface phosphorus loss. In the end, we ended up making some small tweaks to both the Maryland phosphorus management tool (PMT) and the North Carolina phosphorus loss assessment tool (PLAT) that made them score more appropriately against our soils dataset.”

Article by Adam Thomas

Photos courtesy of Amy Shober

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Researchers at the University of Delaware are looking into what causes that gut feeling in livestock animals such as cows and chickens.

Ryan Arsenault, assistant professor in the Department of Animal and Food Sciences in UD’s College of Agriculture and Natural Resources (CANR), arrived at UD in 2015 and since that time, he has worked to set up a lab looking specifically at the gut health of production livestock animals.

Members of Arsenault’s lab—specifically Bridget Aylward, a doctoral level student in CANR, and Casey Johnson, a Master’s level student in CANR—have presented their findings at international conferences such as the European Symposium on Poultry Nutrition in Spain as well as Keystone conferences in Banff, Canada and Dublin, Ireland.

Nexus of Everything

Arsenault said that gut health is a big topic in agriculture as many researchers are looking for alternatives to antibiotics which are almost all focused on the gut.

“We can’t use antibiotics like we used to in food animals. Antibiotics have been used in animal agriculture to keep animals disease free and grow larger. In Europe it’s totally gone, has been for years and years, and it’s getting pulled more and more from the American market so things like probiotics, pre-biotics, post-biotics, feed additives and feed enzymes, everyone’s looking at those as this silver bullet to solve the antibiotic alternative issue,” said Arsenault.

Many of his research projects are funded by industry and look at mode of action and mechanisms for antibiotic alternatives such as yeast cell wall extracts, feed enzymes and feed modifiers.

The trend towards no-antibiotics basically boils down to two main points: the concerns regarding antibiotic resistance that bacteria develop and the negative perception consumers have with regards to the use of antibiotics in animals.

Arsenault said that the gut is important to understand because it’s the center of animal production.

“You need an efficient gut because that’s where all the nutrients are absorbed. You’re not going to have a growing animal without a functioning healthy gut and it’s also the site of entry for a lot of disease causing pathogens,” said Arsenault. “It’s linked to pretty much every other system. For example, the second most innervated organ in the body besides the brain is the gut.”

There is also a huge immune component as more than 50 percent of the immune system is found in the gut.

“The gut is sort of this nexus of everything,” said Arsenault. “It’s basically your gut microbiota—the resident commensal bacteria in your gut—are a big part of being healthy. If you have the ‘good’ bacteria in your gut, you’re more likely to be resistant to infections, your gut’s functioning more efficiently, you can maintain a healthier weight. Diseases like Crohn’s Disease or Ulcerative colitis are, people think, predominantly microbiota related.”

The acquisition of a microbiome as a young chick, baby calf or a baby human has consequences for an entire life span because of how it helps develop an appropriate immune system and an appropriate immune response.

For instance, a lot of allergies and auto immune diseases are linked to how one acquires a microbiome in infancy.

Arsenault said that his lab is interested in looking into how chickens or cows acquire a healthy or unhealthy microbiome and what signals this is providing to the host animal, which feeds into the probiotics question of what the animals should be fed in order to give them a healthy microbiota so their immune system is optimum and they’re absorbing the optimum nutrients.

Focusing on the gut is a trend in human health as well, as probiotics have taken off in popularity and the work being done in Arsenault’s lab ties into the One Health concept, the idea that the health of people is connected to the health of animals and the environment. The most common type of zoonotic disease—diseases that can be passed from animals to humans—are classified as zoonotic gastrointestinal diseases, this includes Salmonella, E.coli and Campylobacter.

International presentations

For their presentations, Johnson and Aylward both focused on issues related to the gut.

Johnson looked at feed additives as alternatives to antibiotics and how they respond with necrotic enteritis, or inflammatory dead gut disease, in chickens which is a huge problem facing the Delmarva poultry industry due to antibiotic feed restrictions.

“We were looking at their products which is crude yeast cell wall extracts which trigger immune receptors and we were looking at the purified forms of these yeasts cell wall extracts and at the differences and the efficacies of these as antibiotic alternatives. The more purified products seemed to have a better response,” said Johnson.

Because yeast is a fungus and not a bacteria, they initiate and bind to different receptors in the gut and do different things to the immune system than bacteria.

Arsenault explained that there’s been a lot of work in poultry on yeast feed additives as immune modulators because “They’re not really stimulating the immune system, they’re not dampening the immune system, they’re kind of priming or modulating it.”

Aylward’s poster presentation in Banff looked at pattern recognition receptors, which are receptors in the immune system that recognize a specific universal microbe motif such as a set of nucleic acids in a form only found in bacteria, with regards to chicken macrophage cell lines.

A macrophage is a large cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection.

The macrophages were treated with butyrate—considered a post-biotic—and forskolin—a plant extract that people use as a weight loss supplement.

Aylward worked on the kinome array analysis of how signaling in the cells changed after administration of these different feed additives.

Her presentation in Dublin looked at eight random dairy cows that were free of pathogens to establish the baseline normal immune cell signaling in the gut of those cows.

Departmental focus

In addition to his research on gut health, Arsenault is also on the organizing board of the annual Symposium on Gut Health in Production of Food Animals, an international conference on all aspects of gut health for all food animal species. He has been invited to speak on the topic of gut health in Brazil, Spain, Canada and the U.S. and co-edited an e-book on gut health research.

The Department of Animal and Food Sciences also has Amy Biddle, assistant professor of animal and food sciences, who co-teaches a gut microbiome microbial and host perspectives class with Arsenault.

Biddle’s work includes the Equine Gut Microbiome project in which her lab is tackling many of the fundamental questions behind the role of bacteria in the horse gut in health and disease.

Robert Dyer, associate professor in ANFS, and Tanya Gressley, associate professor and dairy nutritionist in ANFS, are also looking carefully at the gut health of animals.

Article by Adam Thomas

With over 105,000 acres of small grain crops planted in Delaware in 2016, at a value of $24 million, it is vital to keep the industry up to date on the latest developments in disease resistance.

One disease of particular interest is Fusarium head blight (FHB), considered the most damaging pathogen of small grains worldwide that reduces yields of wheat and barley and also contaminates grain with the carcinogenic mycotoxin known as deoxynivelenol (DON).

To help area growers, the University of Delaware’s Cooperative Extension Field Crop Pathology team has joined with a group from the University of Maryland to look at varieties of small grains with moderate resistance to FHB and DON.

Using a misted nursery, a nursery with plants that get mist irrigated every night by a sprinkler system, located at the University of Maryland’s Beltsville facility, the group assessed 57 wheat varieties for FHB and DON in 2017, collecting data and sharing that data on-line, as handouts at meetings and as mailers to growers in Delaware and Maryland.

From UD’s prospective, the study was led by Nathan Kleczewski, extension field crops plant pathologist, who said that mist irrigating the different varieties every night allows the disease to develop more consistently, enabling the researchers to provide more consistent and reliable measures of FHB and DON resistance.

“You might have two varieties,” said Kleczewski.  “Variety one might flower on Monday and variety two might flower on Friday. Now, if you get heavy rains on Monday and it is dry for the next several days or weeks, you may come back later and think, ‘Variety two is resistant to FHB.’ In reality, the environment was not conducive for disease, that’s why symptoms were not present on variety two.”

The researchers are evaluating commercial varieties and some varieties that haven’t been released yet to see which ones have the best resistance to head blight and DON.

“What we’re able to do is provide the growers with a nice, unbiased evaluation of the different varieties for head blight,” said Kleczewski, who noted that different companies sometimes use different standards when they rate their varieties for diseases.

“We compare everything across the board and we line up the varieties where they are relative to one another, not just within the company,” said Kleczewski.

The idea of the misted nursery research is to try and promote the utilization of newer varieties of wheat that have more resistance to FHB with the end result being that growers in the region will suffer fewer losses to head blight and DON.

“In the end, grain prices might go up because there will be less mycotoxin contamination, maybe we can minimize the amount of pesticides that are going on the plants and improve the profitability of the growers, the millers and everybody in the whole chain,” said Kleczewski.

Head Blight

Kleczewski said that FHB is a fungal disease that grows mostly on corn residue. Around Delaware and in the Chesapeake Bay area, there is a lot of no-till agriculture, which means that crops are planted onto residue and not tilled or buried material.

Wheat is usually planted after corn resulting in left over corn residue on fields which can be used as a food source for FHB. The pathogen overwinters on corn and in the spring, when the wheat starts to flower, spores are produced on the corn and can infect the heads of wheat during wet rainy periods.

“When the pathogen infects the head, it can cause yield loss because it chokes off the water and nutrient movement to the grain so that the grains aren’t as big, they don’t fill up with sugars as nicely, and they lose quality,” said Kleczewski.

The fungus can also produce a toxin, such as DON, and that toxin can deceive growers into thinking that their crop is good because it doesn’t appear to have head blight but it could be susceptible to accumulation of the toxins.

“We screen not just for visual symptoms but also for the mycotoxin. If our grain buyers here in Delaware buy a lot of wheat with a lot of mycotoxin, they can’t sell it to the people in Pennsylvania where they need to sell it so what they end up doing is bringing in grain from areas like Brazil or Canada and that costs them money,” said Kleczewski. “When they have to do that, it also lowers the price of wheat for our growers and so we want to try and minimize the amount of mycotoxin in our grain to really help everybody out in the long run.”

UD worked with Jason Wight, assistant research scientist at the University of Maryland, and the Variety Trials team at the University of Maryland on the project.

The Maryland team plants, maintains and harvests the plots. Kleczewski’s group inoculates the site with corn infested with the FHB pathogen, rates the varieties, and evaluates FHB and DON data.

For information on the researcher’s findings, visit Kleczewski’s website and Scabsmart. The data can also be found on the small grain variety trials website run out of the University of Maryland.

Article by Adam Thomas

Deb Jaisi, associate professor in the Department of Plant and Soil Sciences at the University of Delaware, has received a research fellowship through a new National Science Foundation (NSF) initiative that focuses on developing the next generation of U.S. researchers.

The award from NSF’s Established Program to Stimulate Competitive Research (EPSCoR) allows awardees to make extended collaborative visits to laboratories and scientific centers, establish partnerships with researchers with complementary expertise, learn new techniques, have access to sophisticated equipment and shift their research focus in new directions.

The two-year, $261,000 award will enable Jaisi and his graduate student to spend six months each year working with scientists at the California Institute of Technology to use a suite of sophisticated instrumentation to determine the specific forms and concentrations of phosphorus in soil and water.

Delaware is one of 24 states, the Commonwealth of Puerto Rico, the U.S. Virgin Islands and Guam that are eligible to compete for EPSCoR funding.

Unlike other types of NSF EPSCoR grants, which focus on supporting research centers and partnerships among institutions, the Research Infrastructure Improvement (RII) Track-4 fellowships focus on giving early-career researchers the foundation for collaborations that span their entire careers. NSF announced the 30 RII Track-4 grant recipients on Wednesday, Sept. 20.

“These awards provide early-career researchers with tremendous opportunities and result in EPSCoR institutions gaining faculty members and investigators with cutting-edge research experience, who can help build the vibrant science and engineering laboratories and programs of the future,” said NSF acting EPSCoR head Uma Venkateswaran.

The Delaware EPSCoR program helped recruit Jaisi to UD in 2012, providing start-up funding for his laboratory.

“Deb is one of the really outstanding hires we’ve made through the Delaware EPSCoR program,” said Don Sparks, the S. Hallock du Pont Chair of Soil and Environmental Chemistry and project director for Delaware’s current statewide EPSCoR project. “He’s set up a world-class laboratory and developed innovative techniques for tracing the movement of phosphorus through the environment, establishing quite a reputation for himself in a relatively short period of time.”

Phosphorus and the environment

In January this year Jaisi received an NSF CAREER Award for outstanding early-career scientists that will address the environmental fate of phytate, the most common yet elusive form of organic phosphorus.

Phosphorus, the focus of Jaisi’s research, is a key nutrient for all living organisms but also typically scarce in natural environments. As a component of fertilizers, phosphorus may promote crop growth, but excess phosphorus may build up in soil and be washed into waterways where it stimulates overgrowth of algae and degrades water quality.

“The problem of phosphorus pollution has been very persistent in waterways such as the Chesapeake Bay, despite all of our efforts so far to limit the sources and clean it up,” Jaisi said. “My research team is devoted to gaining a deeper understanding of phosphorus sources and biogeochemical processes to make more progress in improving water quality in the Chesapeake and elsewhere.”

The movement of phosphorus through soil, water and sediment is not straightforward, however, and Jaisi has dedicated his research to understanding the various sources and forms phosphorus may take and their interactions with living and nonliving components of the environment. He has developed new techniques for tracing the sources, transport and transformation of phosphorus using phosphate oxygen isotopes. (Phosphate is a molecule made up of one atom of phosphorus and four atoms of oxygen.)

Isotopes — forms of the same chemical element with different atomic masses — occur in different proportions depending on their source. Phosphate derived from synthetic or manure-based fertilizers, for example, will carry different oxygen isotopic signatures than phosphate derived from decaying autumn leaves that have fallen into a stream.

Determining the source, timing, and relative quantities of various phosphorus inputs into waterways, particularly regarding whether they pose immediate risks to water quality, will potentially have a major impact on watershed management decisions.

Jaisi says that working with the expert colleagues and sophisticated tools available at Caltech will enable him to advance his research to a new level. His host at Caltech will be John Eiler, a leading expert on the isotope geochemistry of light elements. The fellowship offered the perfect opportunity to work together for an extended period of time.

Jaisi is looking forward to using the advanced analytical tools at Caltech, especially the nano secondary ion mass spectrometer (nanoSIMS) and laser ablation isotope mass spectrometer (LA-IRMS), one of only a handful of such facilities in the U.S., to develop new methods of analyzing stable isotopes of phosphate in complex soil matrices. Developing methods and expertise on this equipment will be a key step toward future funding proposals to bring SIMS and LA-IRMS capability to Delaware.

“This fellowship has really been an exciting development and will support my dream of developing advanced and innovative analytical methods in my research,” he said. “In fact, methodological limitations are essentially the roadblocks of phosphorus research. This high-risk, high-return type of research aims to develop two independent isotope systematics that together will significantly improve the resolution of sources and processes involving phosphorus in the environment, and thus may provoke the need for reinterpreting published literature.”

Article by Beth Chajes

Photo by Evan Krape

This article can also be viewed on UDaily.

The University of Delaware’s Janine Sherrier is a co-leader of a multi-institutional team that recently received a four-year, $5,972,497 grant from the National Science Foundation to conduct research on the functional genomics of beneficial legume microbe interactions.

These funds were awarded to the team after their recent completion of a highly-successful research program supported by a previous $6,733,426 award from the National Science Foundation.

Sherrier, professor in the Department of Plant and Soil Sciences in UD’s College of Agriculture and Natural Resources, professor of biological sciences and research team leader at the Delaware Biotechnology Institute, is a co-principal Investigator on the project.  Other team leaders include lead scientist Michael Udvardi, Chief Scientific Officer at the Noble Research Institute; Maria Harrison, the William H. Crocker Professor at the Boyce Thompson Institute at Cornell University; Rebecca Dickstein, professor in the Department of Biological Sciences at the University of North Texas; and Catalina Pislariu, a new professor at Texas Woman’s University.

Sherrier said that in this study, the researchers are “focusing on genetic components of the plant which regulate interactions between a legume forage crop and beneficial bacterial and fungal soil microbes. Just as humans require microbes to help us absorb nutrients from our food and maintain a robust immune system, plants also perform best when they interact with beneficial microbes. These microbes can provide plants with protection against pathogens and pests, increase plant reliance during stressful environmental conditions, and aide the absorption of essential nutrients from soil,” said Sherrier.

In recent decades, plant breeders have made advances in the production of crop plants with important traits such as increased yield or enhanced disease protection, but Sherrier said, “The practical application of beneficial microbes has not been well studied and this research area offers the promise of the development of new tools to increase crop yields and to lower economic and environmental costs associated with crop production.”

The research project focused on a legume crop because of its current use as a forage crop and its similarity to other important legume crops such as alfalfa, soybean, lima beans, and peanut. Legumes are also known to interact with a beneficial microbe which reduces the requirement to augment fields with nitrogen fertilizers, one area of Sherrier’s research expertise. In this unique interaction, when the bacteria and plant associate successfully, the bacteria are able to convert gaseous nitrogen from the Earth’s atmosphere into a form that is bioavailable for the plant.

“Nitrogen is often the most limiting macronutrient in crop production, and the industrial production of nitrogen fertilizer requires high pressures and high temperatures, conditions which consume large levels of fossil fuels. As demands for fossil fuels continue to increase, the cost of industrially-produced nitrogen fertilizer is passed on to crop producers and food consumers. If growers have an option to use the microbially-supplied nitrogen to support successful crop growth, they could save money and help reduce the carbon footprint of food production,” said Sherrier.

This beneficial interaction to acquire nitrogen is especially relevant to crop production on the coastal soils of Delaware, the rest of the Eastern shore of the U.S., and in California. Agricultural fields in coastal soils like those found in Delaware contain a high percentage of sand, relatively low levels organic content and are susceptible to droughts and floods. Unfortunately, these conditions are not optimal for the long-term survival of beneficial microbes in the soil, and these regional soils do not contain enough of the beneficial bacteria to help crops reach their full yield potentials.

“Growers are facing increasing pressures to increase crop yields, while reducing impacts of crop production on the environment. This research is important because it will provide additional tools to growers to support healthy crop growth. Individuals may not choose to use microbes in every application, but growers will have a greater selection of resources to respond to the challenging conditions they encounter during each growing season,” said Sherrier.

Therefore, in addition to the laboratory research in this project, Sherrier is working with UD’s Cooperative Extension specialists to demonstrate how growers can add beneficial microbes to the soil at the time of planting. In addition, the group researchers are enthusiastic about the training they will provide for students, post-docs and the general public about the importance of microbes and soil health for crop production.“Since our team has been entrusted with federal funds to support our research, we are committed to sharing the results of the research to benefit the public,” said Sherrier.

Importantly, Debra Coffey, an educational researcher with the Center for Research in Education and Social Policy, will lead assessments of the program’s entire outreach and training efforts to measure the impact of their work and help the team continue to improve the impact of their diverse outreach program.

At UD, specifically, Sherrier’s team will collaborate with UD’s 4-H program to lead an educational 4-H camp called Marvelous Microbes camp which teams microbiology and encourages students from diverse backgrounds to pursue careers in sciences. The group will conduct training sessions for adults at farmer’s markets and farm stands, and they also developed programming for students of all ages in Alabama, Texas, and New York.

Postdoctoral researchers, graduate and undergraduate students participating in the program from all of the research institutions will take part in a rigorous training program. The senior team leaders will also provide training for members of the global scientific research community during annual workshops to demonstrate how the U.S.-generated resources can be used to benefit additional scientific research programs.

Article by Adam Thomas

Photo by Evan Krape

This article can also be viewed on UDaily.

The world’s coastal ecosystems — areas such as tidal marshes and mangrove forests — have the potential to store and sequester large amounts of carbon, collectively known as blue carbon.

Because of their importance to the global carbon cycle, former President Barack Obama in 2014 made research on understanding carbon dynamics in these coastal ecosystems a priority.

Despite their role as potential sinks – or storehouses – of carbon, it is still unclear how different biophysical processes influence carbon dynamics in these ecosystems.

Using funds from his recently awarded National Science Foundation Faculty Early Career Development Award, the University of Delaware’s Rodrigo Vargas will establish an outdoor laboratory at the St. Jones Reserve, which is a component of the Delaware National Estuarine Research Reserve (DNERR) and part of the National Estuarine Research Reserves (NERR). His research efforts will contribute to a better understanding of vertical and lateral carbon fluxes — the amount of carbon exchanged between the land and the atmosphere, and the amount of carbon exchanged between the land and the coastal ocean — in tidal coastal wetlands.

Through the prestigious NSF Career Award, Vargas, associate professor in the Department of Plant and Soil Sciences in UD’s College of Agriculture and Natural Resources (CANR), also will work to empower minority students by integrating them into research, educational and outreach activities, and will enhance social capital by strengthening the network of students, science professionals and researchers in salt marshes across Delaware and beyond.

Vertical and lateral fluxes

Vertical carbon fluxes involve the amount of carbon going up and into the atmosphere or from the atmosphere into the ecosystem and will be estimated by measuring fluxes of carbon dioxide (CO₂) and methane (CH₄); two important greenhouse gases.

“The net exchange of CO₂ between the atmosphere and the land-surface is called the net ecosystem exchange,” Vargas said. “If the net ecosystem exchange is negative, it means that CO₂ is being absorbed by the ecosystem. If it’s positive, it means that CO₂ is being released into the atmosphere, and the way we quantify that is with the eddy covariance technique that measures the exchange of mass and energy between the atmosphere and the land-surface.”

In this specific site, the researchers are measuring the exchange of CO₂ and CH₄ between the ecosystem and the atmosphere using the first eddy covariance tower established in the state of Delaware since 2015. The establishment of this tower was partially supported from grants Vargas received from Delaware’s National Aeronautics and Space Administration Established Program to Stimulate Competitive Research (NASA-EPSCOR), the Delaware Coastal Programs (DCP), and a CANR seed grant.

The tower is part of the AmeriFlux network, a consortium of scientists using a network to work with the eddy covariance technique, measuring fluxes of CO₂ and CH₄ at multiple sites across the Americas.

In addition to the vertical fluxes, Vargas explained that is also important to account for lateral fluxes in salt marshes, as well.

Because they’re located in the transition between land and ocean—the terrestrial-aquatic interface—the challenge for salt marshes is that their biogeochemistry is also influenced by tides, which bring matter and energy in as they rise. When tides retreat, they pull out matter and energy, which makes it very challenging to understand the carbon cycle on these ecosystems.

“Recent studies have shown that there’s substantial lateral carbon exports from these ecosystems toward the coastal ocean and that is something that we also would like to understand,” said Vargas. “It’s a very large challenge and we are starting studies with the overarching goal to understand how different biophysical factors regulate vertical and lateral carbon fluxes in tidal salt marshes.”

Remote cameras

The site is also equipped with digital cameras that are able to take automatic pictures of the ecosystem to study plant phenology. Plant phenology informs about the periodic life cycles of plants such as flowering or the timing of leaf-out. The images are taken in color and also in infrared, which allows the researchers to see the greening of the ecosystem. That information is used to understand the carbon dynamics of ecosystems based on repeated photography, referred to as near-surface remote sensing.

“You can see the greenness index to quantify how green the ecosystem is and it peaked by mid-August this year, and then you start losing that greening as part of the annual vegetation cycle. It is also a fantastic opportunity for citizen science and outreach,” said Vargas.

The digital camera not only tells the researchers about the greening of the site but also about events they might not have otherwise been able to research, such as when major flood events occurred in 2015 and 2016.

“One flood event was caused by the surge of Hurricane Joaquin. With the cameras, we were able to monitor how high and extensive the water level was. In 2016, we had another flood, but this flood was not because of ocean storms, it was because of an inland storm that brought water through the St. Jones River and flooded our site,” said Vargas.

All images are available online in real-time as part of the PhenoCam network to help improve transparency and data sharing among the broader scientific community.

Educational component

Vargas will also use the award to provide eighth grade students — who are usually learning about the carbon cycle through their class curriculum — a chance to get a hands-on learning experience related to carbon.

Vargas plans to work with professionals at DNREC and the St. Jones Reserve, as well as with Amy Trauth-Nare, senior associate director of UD’s Professional and Continuing Studies, to develop a module using phenomena driven instruction — or place-based instruction, such as learning at the St. Jones Reserve — to specifically address topics on carbon and energy exchange in ecosystems.

In addition, Vargas is looking to create opportunities for undergraduate minority students participating in UD’s Associate in Arts Program (AAP) to promote academic success in science, technology, engineering and mathematics (STEM) fields.

“One of the things that I have been working on since I started at UD is to empower underrepresented students. By providing scholastic opportunities and enhancing social capital, we strengthen the network of students, science professionals and researchers in Delaware and beyond,” said Vargas. “I am Hispanic and Hispanic professors are a minority at UD, and Hispanic students are also a minority at UD. Thus, I have a strong commitment to supporting underrepresented undergraduate and graduate students in STEM fields. That’s a big push on this proposal.”

Vargas will work with David Satran, director of the Associate in Arts Program, to customize opportunities for the AAP students, and will incorporate his current graduate students as mentors for the AAP students.

Article by Adam Thomas

Photo by Evan Krape

University of Delaware doctoral student Desiree Narango is researching trees and shrubs planted in the lawns of homeowners throughout the Washington D.C., Maryland and Northern Virginia areas to assess how those choices are impacting food webs.

Narango, a doctoral student working with Doug Tallamy, professor of entomology in the Department of Entomology and Wildlife Ecology, is also associated with the Smithsonian Migratory Bird Center and works through a citizen-science program called “Neighborhood Nest Watch.” Narango is co-advised by Pete Marra, director of the Smithsonian Migratory Bird Center.

Through her research, Narango looks at breeding birds and the food resources they need, such as insects and caterpillars.

Different trees vary in how much food they provide birds and Narango said she has a network of homeowners in the D.C. metropolitan area that allowed her to use their yards for her study. Over the course of the four-year study, Narango has looked at 203 yards.

One thing that has stood out to her is the sheer number of different trees that are planted in these yards.

“We focus on woody plants—so trees and shrubs—and we’ve documented over 375 different species in these 203 yards. Which is crazy,” said Narango who added that it became apparent quickly that some trees are better than others with regards to sustaining food webs.

“We just had a paper come out in the journal of Biological Conservation where we show that native trees are better at providing caterpillars for birds which is a really important food resource,” said Narango. “Native trees are better, hands down, but even among the native trees, there’s some that are better than others so things like oaks and cherries and elms are highly productive for caterpillars so they have lots of good food for the birds.”

Narango added that there are a lot of non-native plants—such as zelkova, ginkgo, and lilac—that don’t provide any resources for breeding birds.

“Those species are true non-natives so they’re not related to anything here and they provide almost nothing in terms of caterpillars for birds,” said Narango. “There’s also species like Japanese cherry and Japanese maple that are non-native but are related to our native maples and cherries. We found that those species have an average of 40 percent fewer caterpillars than the native versions of that tree. If you had a choice between a black cherry and a Japanese cherry and if you’re interested in food for birds, then you should choose the native version.”

Narango said that a problem home owners may face when trying to select native versions of plants is that a lot of the big box stores don’t carry them.

“There are a lot of really great small nurseries that have many native plants that are productive in terms of caterpillars and are also very beautiful,” said Narango. “You definitely don’t have to sacrifice beauty to get plants that are ecologically beneficial. There’s a lot to choose from so you can have beauty, you can have fruit and then also have food for birds too. It’s all interconnected.”

As for the most eye-opening aspect of her research, Narango said that it has to be the tremendous amount of diversity in bugs and birds in people’s back yards.

“A lot of people think you need to go to the woods to see beautiful butterflies or beautiful birds but they’re actually in people’s back yards too,” said Narango.

In the group’s bird surveys, they documented 98 different bird species.

Narango focuses on the Carolina Chickadee and said that she would follow individual birds around to see what trees they were choosing. One of the major findings in her paper is that the number of caterpillar species a plant supports predicts how strongly chickadees prefer it.

“When these birds would choose a tree, all the other birds in the neighborhood were choosing those trees too so we would see these amazing warblers that don’t breed in Delaware or in D.C. but are migrating through and they’re using all these suburban habitats on their way north. In a way, our chickadees were telling us what all of the birds want during that period,” said Narango.

As a landscaper herself, Narango added that it was surprising to see how much life happened in her own back yard when she started planting the right species.

“I planted this flower called ironweed and the first year it was there, I had the specialist bees that use that flower and then I have caterpillars in my shrubs and it’s really cool how quickly you can see life be attracted to your yard when you plant the right species,” said Narango.

Article by Adam Thomas

Photo courtesy of Desiree Narango and Doug Tallamy

When conducting research in remote areas to get population estimates on elusive animals, it’s important to make sure that the camera traps which will capture images of those animals are set up properly. Once the camera traps are placed, they can’t be adjusted and the only time they’ll be looked at again is when they’re picked up at the end of the study.

Thanks to the Brandywine Zoo, University of Delaware researcher Jennifer McCarthy was able to test various camera heights, distances, settings and bait and scent stations to see how to best set up her cameras for an upcoming research project looking at the elusive jaguarundi cat in Panama’s Mamoni Valley.

The research is being done in partnership with the Mamoni Valley Preserve and Kaminando, a wildlife conservation organization.

McCarthy, an affiliated faculty member in the Department of Entomology and Wildlife Ecology in UD’s College of Agriculture and Natural Resources (CANR), said that her group will use the pictures to try and identify a few individuals through specific markings—such as scars or ear notches.

Unlike jaguars, which can be identified using spot patterns, the jaguarundi are all one color and it is harder to identify individuals so having good photos is critical for the researchers.

“We’re trying to get good pictures of their faces and their bodies but we don’t get a lot of time to practice and play with different distances when we’re out in the field,” said McCarthy. “The Brandywine Zoo was incredible because I called and said ‘We’re trying to put these cameras out in Panama, is there any way we could practice on your cats?’ and they said, ‘Yes, that’d be great.’ They were wonderful.”

This study will be one of the first to measure the population density of jaguarundi which are found throughout Central and South America.

“They’re thought to be really common because people see them relatively often but there’s never been a study on them,” McCarthy said. “All the information we have comes from photos that have been obtained during other studies and people have kind of ignored them thinking that they’re pretty common. We have a hunch that we see them because they’re a diurnal species, which means they’re active during the day, so they might not be as numerous as we think.”

McCarthy, who is working on the project with Kyle McCarthy, assistant professor of wildlife ecology, and Jeffrey Conner Maxwell, a senior in CANR, said that they set up two cameras each in three different enclosures of three different animals — the bobcat enclosure, the serval enclosure and the capybara enclosure — and put baits at different distances.

“We measured different distances from the cameras and we were able to see, ‘Ok, if we set our camera this far from the trail, we’re getting really good pictures and if we set our camera at this height, we’re able to get good face photos,’” said McCarthy.

Over the three-day period, they were able to capture almost 4,000 photos which gave them an idea of how to set up their cameras when they ventured to Panama.

The researchers set up 34 cameras in Panama in June and are going to pick them up in October.

Because of the remoteness of their location, McCarthy stressed that it is of the utmost importance to make sure they’re set up properly the first time.

“We can’t go back and check them so we want to make sure we do everything right the first time and the Brandywine Zoo was great in helping us to hopefully do that,” said McCarthy.

The researchers were also able to try out different lures and scents—such as Calvin Klein’s Obsession perfume—that will hopefully get the cats in front of the cameras out in the wild.

“We have used Obsession before in the field but at the Brandywine Zoo, we tried some different scents,” said McCarthy who explained that there have been studies that looked at different perfumes at other zoos.

“Jaguars are really attracted to Obsession and Chanel No. 5,” said McCarthy. “I always think we’re out in the jungle for three or four days and it’s pretty rough but we always smell really, really good.”

McCarthy stressed that it was great to have the Brandywine Zoo as a partner on the project and that zoos often play an important, behind the scenes role in conservation projects.

“This is a way that we get to work with wild animals and we get a lot of data that would take us years to collect in the field,” said McCarthy. “This will really help us with animals in the wild. It’s a great partnership and they were great to work with.”

Article by Adam Thomas

Photos courtesy of Jennifer McCarthy

This article can also be viewed on UDaily.

Throughout the United States, toxic algal blooms are wreaking havoc on bodies of water, causing pollution and having harmful effects on people, fish and marine mammals.

One of the main contributors to these algal blooms is excess phosphorus that runs off from agricultural fields and while there has been a lot of efforts in recent years by farmers to improve agricultural management, the problem persists and there is still a lot of work to be done.

In a paper published recently in the Journal of Soil and Water Conservation, the University of Delaware’s Leah Palm-Forster met with farmers in northwest Ohio to test out different incentives that would promote the use of best management practices (BMPs) to help curb the excess phosphorus runoff from their fields.

Palm-Forster, assistant professor in the Department of Applied Economics and Statistics in UD’s College of Agriculture and Natural Resources, collected the data for the study in 2013 while she was a doctoral student at Michigan State University. Palm-Forster and her co-authors—Scott Swinton, professor, and Robert Shupp, associate professor both at Michigan State University—travelled to four different locations and spoke with 49 farmers, looking specifically at farms that could have an impact on Lake Erie, which was hit earlier this year with an algal bloom that stretched over 700 miles.

The researchers used four different incentives for their study—a cash payment, a cash payment with BMP insurance, a tax credit and a certification price premium—by the cost per pound of phosphorus runoff reduction to see which incentives the farmers most preferred.

“For this study, we used an artificial reverse auction, meaning that farmers didn’t have to go back to their farm and actually do any of these practices. We were trying to pilot test these incentives in a controlled environment, so although it was artificial, they actually were receiving real cash payments based on how they performed during the session,” said Palm-Forster.

The farmers had mock farms which were designed to be typical farms in the Lake Erie watershed and they were given information about baseline management practices that they used and then they were given three different practices that they could bid on.

“We learned a couple interesting things. First of all, there didn’t seem to be a lot of differences between the bids for a cash payment or a tax credit which is interesting because it means we might have some flexibility in how we design programs. If there were the ability to create a tax credit that would be comparable, then we may be able to motivate this kind of management change through that mechanism instead of giving cash payments,” said Palm-Forster.

Another surprising result was that the farmers asked for more money for the incentive where they were given a cash payment plus insurance.

“You would expect them to bid less because you’re giving them this insurance for free, so you would expect that they would request less cash in order to adopt a practice but they were very skeptical about how insurance would work in this particular setting,” said Palm-Forster. “We learned in focus groups afterward that they assumed that there were going to be more transaction costs—time, effort, money being spent trying to comply with program rules and just maintain eligibility—and they didn’t view that as being attractive at all,” said Palm-Forster.

Farmers also seemed willing to accept the certification price premium as long as it would be comparable to an equivalent amount of cash payment. Palm-Forster said that the issue there is that if it happened in real life, it wouldn’t be targeted towards only environmentally vulnerable areas.

“If you imagine there’s this certification price premium, and any farmer who is willing to do these practices could be eligible for the premium, that means a farmer that’s on a piece of land that’s not as sensitive in an environmental sense would be getting the same price premium as a farmer that was on a really environmentally vulnerable piece of land, which is not going to result in the most cost-effective use of those dollars,” said Palm-Forster.

One of the most important aspects of this research according to Palm-Forster was that the researchers went out in the world and interacted with actual farmers to hear their preferences.

“Talking to the real decision makers is key. It can be difficult to get farmers to engage with you but it’s really important and we learned so much from working with them in that setting,” said Palm-Forster. “After we did the experiments, we had focus group discussions which let us understand why they were making these decisions in the experiment. This particular paper was enriched by having that understanding of where the farmers were coming from, which was facilitated by the focus groups.”

While this study focused on Lake Erie, it can be applicable to other areas of the country such as the Chesapeake Bay and the Mississippi River Basin.

These sorts of economic experiments are important as policy makers need to get as much information as possible from actual farmers to hopefully one day roll out incentive programs that the majority of farmers prefer.

“You want to do all these things before you try to roll out this type of program because you need to learn what would work and what wouldn’t. This would be one piece of all of that ground work. There are a lot of projects right now in the western basin, a lot of researchers are thinking about this problem, and a lot of farmers are engaging in regional programs to help improve the lake but it’s still just not enough,” said Palm-Forster.

The research was funded by a grant from the Great Lakes Protection Fund.

Article by Adam Thomas

Visiting Fulbright Scholar Nicolas Carlotto had read many research papers by the University of Delaware’s Jung Youn-Lee during his time studying for his doctorate at the University of Buenos Aires in Argentina.

The agrobiotechnology lab in which Carlotto works and his PhD advisor Ken Kobayshi were also trying their best to perform a Drop-And-See (DANS) technique highlighted in one of her research papers but kept running into road blocks when they tried to follow the papers’ detailed instructions.

Kobayshi e-mailed Lee asking for help and her response was that the best way to learn the technique was for her to show one of his students first hand in her lab and so Carlotto applied for a Fulbright Scholarship, in collaboration with Ministry of Education and Sport of Argentina. Once he obtained the scholarship, he made his way from Argentina to Delaware.

He arrived on July 26 for his three-month internship and immediately started working on perfecting the technique of performing a DANS assay.

The DANS assay is a way for researchers to analyze plasmodesmata—or plant communication through cellular channels—permeability in real time.

Lee, professor in the Department of Plant and Soil Sciences in UD’s College of Agriculture and Natural Resources, said that the technique is exactly as it sounds: researchers drop a membrane permeable, non-fluorescent dye onto the upper side of an intact leaf, then cut off the leaf and look through a confocal microscope to see how much the dye, now fluorescent and membrane impermeable, has spread in the lower side of the leaf. This indicates the aperture of the plasmodesmata, which can be imagined as tubes connecting two cells and indicates how the plant is communicating with itself.

“The spread of the dye indicates how the cells’ communication channel, plasmodesmata, are acting,” said Lee. “If the dye doesn’t spread in a big field, it means that plasmodesmata, the channels are mostly closed so that we can tell how plasmodesmata are active in in-tact plants. That gave us a real handle on measuring the plasmodesmata permeability in real time.”

Carlotto said that he learned from both Lee and Xu Wang, a member of Lee’s lab group and that he was also supported by the Department of Plant and Soil Sciences with funds that let him use the Delaware Biotechnology Institute’s (DBI) Bioimaging Center, an advanced microscopy facility where he has done most of his experiments.

“I learned how to be really consistent with your handling of the experiment. Because perhaps sometimes you don’t focus very well on the health of the plants or on the leaf you want to treat or the time when you set an experiment. You try to do that but sometimes you miss. And coming to a lab where they are really focused on that, it will improve my experience as a scientist,” said Carlotto.

Learning from doing has also helped Carlotto instead of simply trying to learn from reading about the experiment in a paper.

“It’s very different when you see how something is done than when you read about it,” said Carlotto who added that he is excited to show members of his lab how to perform the DANS assay back in Argentina as well as other techniques and tools he worked with at DBI.

As for his time at UD, Carlotto said that it has been a great experience.

“I really like the City of Newark. I’m using the Carpenter Sports Building a lot. I used to swim in Argentina when I was younger and it’s been many years but when I came here and found out about the Carpenter Sports building, I go in to swim and use the machines. UD is really great. The campus is nice and you can really feel and experience the university academic ambience of the United States,” said Carlotto.

Article by Adam Thomas

Photo by Monica Moriak