The Ecosystem Ecology Lab


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The role of intra-specific variation in leaf and root litter chemistry among hybrid poplar genotypes in soil C sequestration. We used a basic ecosystem model to test the hypothesis that the intra-specific variation in leaf and root litter chemistry and decomposition rates among hybrid poplar genotypes has large and sustained impacts on soil carbon sequestration and ultimately alters ecosystem trajectories.

The role of nutrient availability in limiting forest response to global change We examined if previously observed changes in carbon allocation to fine roots is due to N limitation and what an increase in soil C from root inputs might mean for long-term C storage and N cycling in forests.

This research was funded by the DOE Terrestrial Carbon Program

Old-field Community, Climate and Atmospheric Manipulation (OCCAM)

We established a multi-factor climatic change experiment in an old-field to test the relative importance of direct and interactive effects of climatic drivers on ecosystem function.

This research was funded by the DOE Program for Ecosystem Research.

Scaling across levels of biological organization to better understand how climatic change may alter ecosystem function 

We used qRTPCR to assay portions of the ecosystem transcriptome that may be indicative of autotrophic and heterotrophic respiratory activity.

This work was funded by an ORNL LDRD award.

Bridging the gaps in soil carbon and nitrogen cycling: soil microbes as predictors of global climate change?

We examined the relationship between microbial functional gene expression and nutrient processes in soil.

This research is funded by the Microbiology across Campuses Educational and Research Venture (M-CERV) at UT.

Developing a systems biology approach for linking genetic and environmental constraints to primary productivity

This research was funded by the University of Tennessee Joint Directed Research and Development program.

Drought in pinyon-juniper woodlands

On a project lead by Melissa Cregger, we collaborated with Nate McDowell (LANL) and Will Pockman (UNM) on a project at the Sevilleta LTER investigating how soil bacterial and fungal communities respond to experimental changes in precipitation.

Herbivore susceptibility and resistance effects on ecosystems

Research in our lab investigates how insect infestation alters the nitrogen and carbon budget of ecosystems. Long-term studies have identified trees that are resistant and susceptible to herbivores, and because resistance to herbivory has a genetic component, the potential exists for linking population-level variation in plant genetics to key ecosystem processes.

The role of foundation species and faunal biodiversity in ecosystem structure and function

In collaboration with Aaron Ellison (Harvard), Nick Gotelli (UVT), and Nate Sanders (U Copenhagen), we established an experiment to determine if observed changes in ecosystem processes can be accounted for directly by changes in faunal biodiversity, or if there is there a unique interaction between the loss of Hemlock trees and the compositional shifts in associated plant and faunal assemblages.

The role of root exudation and rhizosphere microbial community structure and function in regulating ecosystem carbon flow

We investigated specific linkages between microbial diversity and function, and root exudates.

This research was funded by an ORNL LDRD grant.

Initiative for Quaternary Paleoclimate Research

The IQPR research group brings together researchers in the geography, anthropology, earth and planetary sciences, anthropology, engineering, and ecology and evolutionary biology departments who are pursuing research focused on the climates and environments of the Quaternary period. We are starting a project aimed at linking climate information from tree rings with soil carbon data.

Hemi-parasitic plant impacts on communities and ecosystems

Though much is known about how parasitic plants influence host performance, their roles in shaping community- and ecosystem-level processes remain relatively unexamined. We examined the effects of Castilleja miniata on the structure and dynamics of plant communities, and ecosystem processes near Gothic, Colorado.

What controls fungal communities in decomposing logs?

On a project lead by Emily Austin, we are collaborating with Chris Schadt (ORNL) to investigate what factors structure lignocellulolytic fungal communities and how changes in those communities alter wood decomposition rates under warming.

Incorporating soil biota in a long-term climate change experiment

In collaboration with Aaron Ellison (Harvard Forest), Nick Gottelli (UVM), Nathan Sanders (U Copenhagen), Rob Dunn (NCSU), Melissa Cregger (ORNL), Emily Austin (New Hampshire) we are using experimental warming studies at both Harvard Forest, MA and Duke Forest, NC to quantify the response of soil and wood biota to temperature.

Ant impacts on communities and ecosystems

Ants can alter the soil they nest in by redistributing nutrients to create islands of fertility on the landscape. We ask: will the impact of ants be seen in plant and soil communities for decades after the colony leaves, or will the impact diminish quickly?