Rodrigo Vargas joins CANR faculty

August 29, 2013 under CANR News

Rodrigo Bargas joins CANR facultyIn October of 2012, Rodrigo Vargas joined the community of the College of Agriculture and Natural Resources (CANR) as an assistant professor in the Department of Plant and Soil Sciences.

Since joining UD, Vargas has successfully secured over $1 million in grants as a principal investigator supported by the National Aeronautics and Space Administration (NASA), the United States Department of Agriculture (USDA), and the University of Delaware Research Foundation (UDRF). His research group has active study sites in Baja California, Delaware, and Maryland and collaborates with scientists across the United States, Asia, Europe and Mexico to understand how land ecosystems respond to climate variability, extreme events, and global environmental change.

Working at CANR, he has actively taken on multiple research endeavors. First, supported by a NASA grant, he is testing different approaches to improve a framework for monitoring, reporting and verification (MRV) to support implementation of Reduction of Emissions by Deforestation and Degradation (REDD+) across a gradient of forests in Mexico. This research involves collaboration with the US Forest Service, the Mexican Forest Service (CONAFOR) and multiple research institutions in Mexico.

Secondly, funded by a USDA grant, he is investigating the effect of extreme climate events on greenhouse gas fluxes in a watershed near UD’s campus by using state-of-the-art instrumentation for continuous measurements of carbon dioxide, methane, and nitrous oxide fluxes from soils. This research involves collaboration with Shreeram Inamdar, associate professor in the Department of Plant and Soil Sciences.

Lastly, funded by a UDRF grant, he is looking at the size, age, and use of nonstructural carbon reserves (NSC’s) in long-lived plants in the deserts of Baja California, Mexico.  His results are providing insights about the physiological mechanisms of carbohydrate allocation and long-term plant survival in water-limited ecosystems.

“Several plant species in the central desert of Baja California can live for over 400 years under limited water availability and climate variability including decadal droughts,” said Vargas.

Preliminarily results show that new fine roots of desert palms and cactus are produced using “old” NSC reserves that are more than 20 years old. Vargas’ group has also found that the age of NSC reserves inside the plants can have a mean age of over 60 years.

“This means that these plants can store NSC reserves and keep them for a long time and then use them to produce new structures such as fine roots,” said Vargas.

Vargas said he is extremely lucky to have rapidly found friends among the UD community who support him and have made him feel welcome in Newark. His time here has already afforded him the opportunity to be exposed to and apply an array of various research techniques from multiple disciplines such as computer science, micrometeorology, remote sensing, and soil ecology.

Offering a sincere thanks to all of his new friends here at the CANR, he said “I have found amazing colleagues, leaders, and students across UD, and the working atmosphere is excellent to nourish and develop high quality research.”

As an undergraduate, Vargas studied biology in Mexico at the Universidad Nacional Autónoma de Mexico (UNAM), one of the largest universities in the world with over 350,000 students. It was there that he began his research career, studying nitrogen fixation of microbial mats in a tropical wetland at the Yucatan Peninsula.

He went on to earn a PhD at the University of California-Riverside where his research focused on how extreme events such as fires and hurricanes influenced carbon dynamics in regenerating forests. Through a combination of biometric forest measurements and experimental forest management techniques, he demonstrated the large capability of these forests to store carbon above and below ground.

Vargas also studied the effects of hurricane disturbance on CO2 fluxes within the soil, finding unprecedented rates of CO2 emissions from soil to atmosphere. Lastly, he demonstrated the unexpected capacity of plants to allocate old stored carbon to produce fine roots following a hurricane disturbance. In light of the east coasts’ late experience with Hurricane Sandy, Vargas’ past work shows the implications these weather phenomena’s have on the fate of stored carbon in plants.

In addition to this work, Vargas also worked on a side-project funded by the National Science Foundation studying belowground carbon dynamics in the San Jacinto Mountains of Southern California. This study allowed him to use a wireless network of soil sensors to measure CO2 fluxes and the relations with fine root dynamics.  “One of the most exciting results is that we demonstrated that fast and continuous fine root measurements (daily and sub-daily) are needed to quantify and understand belowground carbon dynamics,” said Vargas.

Following his PhD, Vargas was a postdoctoral fellow at the University of California-Berkeley where he interacted with scientists around the world within FLUXNET, the international consortium of eddy covariance scientists.  “My work focused on regional and global synthesis studies on water and CO2 fluxes of terrestrial ecosystems, combining measurements and ecological process-based models,” said Vargas.

Before arriving at UD, Vargas returned to Mexico to work as an assistant research professor at a national research center in Baja California, Mexico (CICESE). Here he led synthesis studies on ocean-to-atmosphere CO2 fluxes while also continuing measurements of water and CO2 fluxes in a shrub land ecosystem in Baja California. His interest in the effects of land use change on such fluxes also led him to coordinate the consolidation of the Mexican eddy covariance network (MexFlux), where his research group is working on a first generation of nationwide synthesis studies.

Article by Angela Carcione

Share

CANR announces 2012 Benton graduate student award winners

June 25, 2012 under CANR News

The University of Delaware’s College of Agriculture and Natural Resources (CANR) has announced the winners of the 2012 William J. Benton Graduate Student Awards. The 2012 recipients are Rachael Vaicunas, Jixian Zhai and Kirsten Hirneisen.

The awards were established in honor of William J. Benton, former CANR associate dean of research and professor in the Department of Animal and Food Sciences (ANFS).

Rachael Vaicunas

Vaicunas received her undergraduate and graduate degrees from the Department of Bioresources Engineering, and she said that studying in the department “was a great experience because it provided me with valuable skills that will be useful for my future as an engineer.”

She is researching water quality throughout the state of Delaware, specifically looking at “concentrations of hormones and antibiotics in surface waters across the state and how different land uses affect water quality.”

Vaicunas said that receiving the Benton Award has made her “feel like I brought value to the College of Agriculture and Natural Resources.” She also wanted to acknowledge her graduate adviser, Shreeram Inamdar, associate professor in the Department of Plant and Soil Sciences (PLSC), as she called him “a great mentor and motivator throughout my time at UD.”

Jixian Zhai

Zhai, a doctoral student in CANR, said his research focuses on understanding the roles of small RNA molecules in plant development and disease resistance. He conducts his research by utilizing high throughput sequencing technology, studying the small RNA molecules in a variety of plant species.

Zhai said that he is “really honored to receive this award and very grateful to the donors who always support graduate research in CANR. I believe this is an important step in my career and I am deeply motivated to live up to the expectation of this prestigious award.”

Zhai called his adviser, Blake Meyers, Edward F. and Elizabeth Goodman Rosenberg Professor of Plant and Soil Sciences and chair of the department, an “extraordinary adviser” and he wanted to thank Meyers for “all the guidance as well as the freedom that he gave me on my research.”

Kirsten Hirneisen

Hirneisen, also a doctoral student in CANR, said that receiving the Benton Award is “a great honor. Past recipients have been wonderful students and great scientists and it’s a wonderful feeling to be associated with them through this award.”

Hirneisen’s area of research is microbial food safety and she said that she enjoys working in the field because it encompasses many different areas. “As a food safety microbiologist; I get to be involved in all these areas to control hazards from the field to fork.”

Her doctoral research focuses on “the enteric viruses, including Hepatitis A Virus and human noroviruses, and their interactions with fresh produce in a field environment. The impacts of my research helps assess the risk of human pathogen contamination of produce and aids in the development of strategies to ensure a safe food supply.”

Hirneisen said that her adviser Kali Kniel, associate professor of ANFS, has been “a wonderful mentor to me and a great role model.”

Article by Adam Thomas

This article can also be viewed on UDaily

 

Share

Experimental watershed provides new insights, rich educational experience

June 25, 2012 under CANR News

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

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

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

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

Network data collection

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

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

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

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

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

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

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

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

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

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

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

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

Teaching resource

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

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

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

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

Article by Adam Thomas

Share

UD professors gear up for study on lawns, water quality and ecosystem services

October 6, 2011 under CANR News, Cooperative Extension

Taking a fresh look at water quality management, a University of Delaware College of Agriculture and Natural Resources (CANR) research team is studying how the replacement of urban lawns with more diverse vegetation can help protect the environment and make our landscapes more sustainable.

The researchers have been awarded a $595,000 grant by the U.S. Department of Agriculture (USDA) and will be working at the Winterthur Gardens on their project.

Shreeram Inamdar, CANR associate professor of plant and soil sciences, is the principal investigator and the research team includes Doug Tallamy, chair of the Department of Entomology and Wildlife Ecology; Susan Barton, associate professor in the Department of Plant and Soil Sciences and a Cooperative Extension specialist; Jules Bruck, assistant professor of landscape horticulture and design; and Joshua Duke, professor in the Department of Food and Resource Economics.

One of the main goals of the three-year study, funded through the USDA’s National Institute of Food and Agriculture (NIFA) National Integrated Water Quality program, is to try to curb water pollution at its source — preventing pollution in the first place rather than waiting to treat contaminated water before it enters waterways.

“In the past, standard water quality management has focused on intercepting dirty water before it gets into water systems,” explained Tallamy. “We’re doing the opposite — we’re trying to keep the water clean from the start.”

The researchers believe this can be accomplished by shrinking the lawn and replacing it with more diverse vegetation, thus reducing fertilizer and herbicide inputs and enabling water filtration, which will lead to less storm water runoff and cleaner water.

Diverse vegetation also is expected to provide other natural ecosystem services — such as carbon sequestration, preserving biodiversity and natural pest control — that are associated with mixed vegetation landscapes.

Inamdar noted that the ability to look at both of these aspects is a unique opportunity for the researchers. “One of the great things on this proposal is that we get to look at water quality as well as ecosystem services,” he said. “Not many projects take that view, so I think that’s a very novel approach.”

To conduct the study, the group will be comparing watersheds with different vegetation types at Winterthur.

Barton explained that the group will look at runoff from different types of watersheds at Winterthur — one site will be a mown turf field that will be managed in the manner of a residential lawn and the other will be primarily forest and meadow.

By doing this, Barton explained, “We can directly compare these two streams, which are very close to each other, under the same weather conditions. One gets the residential lawn runoff and one gets the diverse landscape runoff.”

The team has also secured a local homeowner’s landscape for the research. Bruck said the property will be “used as a test garden, and will become a demonstration garden to show these different sustainable principles and practices.”

Barton noted that public tours of the sites will eventually be offered.

Planting will begin next spring and as soon as the team gathers enough information and data, it will provide educational courses at Winterthur to disseminate key information to the public.

Tallamy said that making this information readily available is an effort to “change the status symbol. Right now, the status symbol is a big lawn and we’re trying to make it more diverse.”

This is also one of the main focuses of the Center for Managed Ecosystems, of which Tallamy is the director.

Duke’s role will be to determine how much it would cost a homeowner to manage their property in a more diverse manner, as opposed to how much it costs to simply manage a big lawn. Said Duke, “We suspect that it might not be that lawn is actually the cheapest way to manage things. It may be that it’s cheaper for an owner to manage in a more sustainable manner; they might just not realize it because it’s not the status quo.”

Undergraduate and graduate students will be involved in many aspects of the research, from helping the group gather information on water quality, ecosystem services and the economic implications to helping in the design of the more sustainable garden.

Bruck explained that students in her Basic Landscape Design course will “work through the design process to come up with demonstration plans that will be presented to the University of Delaware Botanical Gardens (UDBG) and then we’ll post the plans on our website, for educational purposes for other homeowners.”

For now, the team is gearing up for the spring and ready to get the study under way, hoping to improve water quality and change the status quo from large lawns to diverse, more sustainable ecosystems.

Article by Adam Thomas

Photo by Danielle Quigley

Graphic courtesy Jules Bruck

This article can also be viewed on UDaily > >

Share

Water science, policy program launched

August 1, 2011 under CANR News

Students in the water science and policy program will have ample opportunities to conduct field research. Here graduate student Justin Bower, undergraduate Tara Harrell and graduate student Martha Corrozi (left to right) use an Australian turbidity tube to measure the clarity of water in Fairfield Run, a tributary of White Clay Creek

The world’s human population is expected to top seven billion by April 2012. Of all the burdens this growing population places on the planet’s resources, none is more critical than the pressure on the world’s fresh water supplies. Just 2.5 percent of Earth’s water is fresh water, and much of that is frozen and unavailable to terrestrial life.

Developing solutions to the problem of meeting the growing need for clean water that are socially acceptable, economically viable and environmentally sustainable is the focus of the new interdisciplinary graduate program in water science and policy at the University of Delaware, which welcomes its first students this fall.

The new program will offer a master of science degree and doctoral degrees with either a water science or a water policy concentration. The curriculum draws on courses from four colleges at UD: the College of Agriculture and Natural Resources, the College of Earth, Ocean, and Environment, the College of Engineering, and the College of Arts and Sciences.

Students in the University-wide program will be advised by any of the 30 or so faculty affiliated with the program. The program will be housed in College of Agriculture and Natural Resources and will be directed by Shreeram Inamdar, associate professor of watershed hydrology.

“We have a really top-notch cadre of faculty representing many disciplines, including hydrology, geology, geography, ecology, climatology, microbiology, plant and soil sciences, environmental chemistry, engineering, resource economics and public policy,” Inamdar said. “We may approach the problem of water from different perspectives, but we share a common goal of better understanding, protecting and managing our precious water resources. The beauty of this program is it provides students greater flexibility in shaping their curriculum and greater opportunities to collaborate with faculty from diverse disciplines and departments.”

The new program was initiated under the auspices of the Delaware Environmental Institute (DENIN), where staff members Jeanette Miller and Amy Broadhurst helped to coordinate the diverse group of interested faculty and the necessary paperwork and approval process to launch the program.

new website has been created to provide prospective students with information about the program. According to Inamdar, there are two new research assistantships available immediately to students in the program whose adviser has a primary appointment in the College of Agriculture and Natural Resources.

“Students who graduate from this program will be able to pursue exciting career opportunities in academia, governmental and nongovernmental agencies, close to home or around the world,” said Inamdar. “The demand for clean, healthy water is going to be very high in the coming century, and so will the demand for our graduates’ expertise.”

Article by Beth Chajes

Photo by Jerry Kauffman

The original article can be viewed online on UDaily.

Share