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Mount Denali above the fall Tundra in Alaska's Denali National Park
Mount Denali above tundra in Alaska's Denali National Park. (Unsplash)

Elizabeth Herndon, staff scientist at Oak Ridge National Laboratory and joint faculty member at the University of Tennessee, Knoxville, has been awarded a grant of nearly $1 million from the National Science Foundation’s Office of Polar Projects to investigate how plants, microorganisms, and minerals compete for phosphorus in the Arctic tundra. Phosphorus is an essential nutrient for life but is in short supply in some environments, putting limits on plant growth and decomposition.

Elizabeth Herndon collects a soil core that will be analyzed for chemical and biological properties, including phosphorus concentration and its chemical form (for example, bound to soil minerals or contained in organic matter).
Elizabeth Herndon collects a soil core that will be analyzed for chemical and biological properties, including phosphorus concentration and its chemical form (for example, bound to soil minerals or contained in organic matter).

Herndon—an environmental geochemist in ORNL’s Environmental Sciences Division who holds a joint appointment with UT’s Department of Earth and Planetary Sciences —leads the project, which will take her to Toolik Field Station, Alaska, to conduct fieldwork. Lauren Kinsman-Costello, a Kent State University assistant professor of biological sciences and regular research collaborator with Herndon, and Michael Weintraub, professor of soil ecology at the University of Toledo, are collaborators on the project.

Plants and microorganisms take up phosphorus from soil through water in the form of dissolved phosphate. Phosphate can bind to metals in the soil, limiting its availability to plants and microorganisms.

“Phosphorus is fundamental to what happens in an ecosystem,” Herndon said.

To better understand how plants, microbes and minerals compete for phosphorus, the research team will look closely at what’s happening in tundra soil where warming and permafrost thaw are altering soil moisture and nutrient availability. The research will determine how soil properties can affect competition for phosphate, with broad consequences for plant growth and carbon dynamics in Arctic ecosystems.

“The Arctic is warming more rapidly than anywhere on the planet and there are many environmental impacts associated with that change,” Herndon said. “As permafrost thaws, you see ground collapse and water flowing across the landscape, which in some areas is damaging infrastructure. Plant communities are also changing. In areas where there once were only little shrubs and grasses, trees are moving in—the forest line is moving north.”

Elizabeth Herndon stands on a palsa, a patch of ground that has permafrost less than a meter below the soil surface. Using special instrumentation, Herndon collects soil water and measures oxygen in the pore space— the void space within soil that can be filled by water or air. In the foreground is a bog area where permafrost has completely thawed and caused the ground to collapse and pool with water.
Elizabeth Herndon stands on a palsa, a patch of ground that has permafrost less than a meter below the soil surface. Using special instrumentation, Herndon collects soil water and measures oxygen in the pore space— the void space within soil that can be filled by water or air. In the foreground is a bog area where permafrost has completely thawed and caused the ground to collapse and pool with water.

Specific to their research work is learning how plants access the nutrients needed to grow. Phosphorus is in limited supply, and its availability controls how much vegetation can grow in an area. The team will examine the processes at play and how the features of the physical environment where a sample is collected—a nearby hill or stream, for example—influence or are affected by phosphorus.

The award also supports a postdoctoral scholar and graduate and undergraduate students. Participants will design data-driven educational activities to communicate scientific results to the public.

Herndon joined ORNL as a staff scientist in August 2019 and received a UT joint faculty appointment in November 2019. She was previously a faculty member at Kent State University.

Read more about Elizabeth Herndon’s academic path to Arctic research on the ORNL website.

CONTACT:

Karen Dunlap (865-974-8674, kdunlap6@utk.edu

Amanda Womac (865-974-2992, awomac1@utk.edu)