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Invisible Organisms with an Enormous Impact

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Understanding the distributions and functions of microscopic fungi and bacteria is what drives new Assistant Professor Stephanie Kivlin’s research.

Stephanie Kivlin“Microbes can sometimes get a bad reputation, causing disease, food spoilage, etc.,” Kivlin says. “But, people are often surprised to learn that most microorganisms are beneficial for humans; increasing crop yields, purifying water, and recycling nutrients from dead plants back into soils.”

Because there are more than 1,000,000,000 microorganisms in a scoop of soil, determining exactly where, when, and how microbes perform these beneficial functions is still an open line of research. These questions motivated Kivlin to follow a career in microbial ecology after being trained as a microbiologist. She has since pursued research to connect the function of these tiny organisms (< 0.01mm) to whole ecosystem scale resource dynamics.

Kivlin’s research occurs in locations near and far from Knoxville. She spends her summers assessing microbial response to the 2016 Chimney Tops 2 fire in the Great Smoky Mountains National Park and elevational patterns of microorganisms and the soil resources they affect in the western Colorado Rockies at the Rocky Mountain Biological Laboratory. The rest of year, she models microbial biogeography and ecosystem resource cycling at regional to global scales.

Students participate in a long-term warming experiment at the RMBL collecting fungal endophytes from grass leaves for metabolic analysis.

Students participate in a long-term warming experiment at the RMBL collecting fungal endophytes from grass leaves for metabolic analysis.

Kivlin is especially thrilled to be joining the UT EEB faculty. “I have always valued and encouraged collaborative science. The unique opportunity to collaborate with plant and soil ecologists, mycologists and spatial ecologists in the UT EEB department combined with associations with ecosystem modelers at the Oak Ridge National Lab is the perfect fit for my research program.”

Kivlin’s field site view from Rosy Point, Gothic, Colorado.

Kivlin’s field site view from Rosy Point, Gothic, Colorado.

Kivlin is no stranger to the excellent microbial and ecosystem ecology group already established in the department. To start her lab, Kivlin brought on recent UT EEB PhD graduates Jessica Moore and Leigh Moorhead, with expertise in ecosystem modeling and response to disturbance, as postdoctoral researchers. Moore and Moorhead took advantage of the UT-ORNL connection by conducting their PhD research at ORNL.

“The unique opportunity to collaborate with leading ecosystem experts at ORNL enticed me to select UT for graduate school, and I’m excited to further my ORNL collaborations throughout my post-doc,” Moore says.

“Ecosystem and microbial ecology have always been a strength of the UT EEB department, so I was exceptionally fortunate to attract two postdoctoral researchers whose graduate careers I had been tracking over the last five years,” Kivlin says. “We are all looking forward to building intra- and inter-departmental scientific synergies!”

The Geography of Ecology

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What’s the difference? How is it that a pest or pathogen can kill its host in one place but not another? Research Assistant Professor Christy Leppanen wants to know.

Leppanen is looking for differences that explain why an invasive insect, the hemlock woolly adelgid (Adelges tsugae or HWA), kills North American eastern hemlocks (Tsuga canadensis) and Carolina hemlocks (T. caroliniana), but not hemlocks from its native range in Asia.

Christy Leppanen“Simply speaking, I am interested in identifying mechanisms responsible for different outcomes when communities are considered the same,” Leppanen says. “For example, a particular insect pest or biocontrol agent kills its host plant in one location, but not another. We increase the likelihood of success and reduce the risk of negative non-target effects when management takes these mechanisms into account.”

Easier said than done. Including these considerations seems intuitive, but discerning differences in communities is challenging. Populations are influenced by direct and indirect interactions, such as with predators, competitors, pathogens, and microbial communities, or host resistance, all influenced by variation in nutrients, phenology, and climate.

“Difficulty transferring population control mechanisms from one location to another might reflect the fact that differences in these systems might not be inconsequential.”

For instance, in eastern North America, hemlock woolly adelgid (HWA) biocontrol using natural enemies translocated from HWA’s native range has not yet proven successful. HWA infests different hemlock species in its native range. Evidence suggests host resistance influences infestations, and while this does not preclude some role of natural enemies, vulnerability in eastern North American hemlocks might override possible population level control by natural enemies.

Leppanen comes from a multidisciplinary research, management, and regulatory background in environmental toxicology, conservation biology, and pest management. Her work with HWA falls within her larger interests to improve pest control, mitigate associated harmful non-target effects, and increase sustainable practices.

“The HWA problem embodies many challenges we face managing nature,” Leppanen says. “We have not confirmed which mechanisms control HWA populations in its native range, but specificity associated with effective biocontrol means its interactions and role in population control must be precisely understood. We sometimes feel pressured, however, to implement before we understand. Additionally, approaches sometimes counter one another; for example, chemical control that is often broad spectrum can have broad non-target impacts, even to natural enemies.”

Leppanen is confident scientists will find solutions.

“Collectively, we’ll keep at it. This is interesting and important work, with new tools and technologies and an enthusiastic and engaged group of participants.”

At UT, Leppanen teaches courses in environmental toxicology and invasion biology, the latter with Professor Daniel Simberloff. She is also the author of an award-winning mock scientific journal. The Bulletin of ZOMBIE Research (BOZR) is a collection of deadpan post-apocalyptic articles that uses popular culture to lure readers into learning about research and technical literature, dissolving barriers to accessing and understanding science.

Illustration by Steven Lee (graphiko.com)

Gross Receives SEC Award

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Professor Louis Gross was honored with the 2018 SEC Faculty Achievement Award this week.  The award recognizes professors from the 14 Southeastern Conference schools who have outstanding records in teaching and scholarship. Honorees from each university receive an honorarium and become their university’s nominee for SEC Professor of the Year, to be awarded later this spring.

The full press release can be viewed at news.utk.edu.

 

Gross Named Fellow of Society for Mathematical Biology

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Louis GrossA distinguished professor of ecology and evolutionary biology and mathematics at the University of Tennessee, Knoxville (UT), Gross is also the founding and current director of the National Institute for Mathematical and Biological Synthesis (NIMBioS) and director of UT’s Institute for Environmental Modeling. His research focuses on computational and mathematical ecology, with applications to plant ecology, conservation biology, natural resource management, and landscape ecology.

Read more at Tennessee Today or the NIMBioS Website

EEB is Hiring

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EEB will be hiring a tenure track faculty member at the Assistant Professor level in the field of Ecosystem Ecology.  Application review will begin October 10, 2016, with a position start date of August 2017.  View the full job advertisement here.

Welcome Susan Kalisz!

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Susan Kalisz joined EEB as professor and head of department on August 1. She comes to UT from the University of Pittsburgh where she was professor of biological sciences for nineteen years and served as director of graduate studies and chair of the graduate program oversight committee.

Kalisz’s research interests are two-pronged: the mating system and the evolutionary process, and biotic interactions, population fitness, and community invasion.

Woody Plants of Kentucky and Tennessee

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Eugene Wofford has co-authored a new book called Woody Plants of Kentucky and Tennessee: The Complete Winter Guide to Their Identification and Use.  The guide enables people to identify trees, shrubs, and woody vines during the winter months, when the absence of leaves and fruit makes plants difficult to recognize.  It also provides notes on practical uses for the plants. The book features more than 400 species and is written for amateurs as well as professional botanists.  It was published in October by the University Press of Kentucky and is also available from Amazon.com.