Research Interests
I am broadly interested in examining how environmental factors drive ecosystem functioning, particularly nutrient cycling, and how these processes are altered due to human environmental change. Of particular interest are the roles that soil conditions and plant species play in driving nutrient transformations.
There are three themes central to my research: 1) Coupling of soil-microbial functioning, 2) Plant diversity and microbial links to biogeochemical cycling, and 3) Plant-soil-microbial feedbacks to the restoration of ecosystem function.
Species growing in the growth chamber at SERC. In my postdoc at the Smithsonian Environmental Research Center (SERC), I am finishing a research project examining how different plant species and plant traits impact freshwater wetland microbial competition and methane production. I have determined that as belowground biomass increases which leads to an increase in the oxygen transported to the microbes in the soil, methane production decreases (Sutton-Grier and Megonigal, In prepartion). I have also examined the impact plant carbon inputs to soil have on microbial respiration and decomposition of soil organic matter via a reciprocal soil transplant experiment. At the Nature Precedings website you can view the presentation I gave of some of these results at the Ecological Society of America conference in Albuquerque, NM, in August 2009.
In my dissertation, I examined how plant species and soil conditions influence nutrient transofmrations in restored wetlands. I focused on wetlands because they are unique ecosystems that connect the terrestrial and aquatic portions of the landscape, providing exciting opportunities for studying nutrient transformations in heterogeneous environments. I specifically focused on nitrogen (N) and carbon (C) dynamics and the connections between the cycling of these two elements. To address the challenges of studying the complex relationships between plants, soils, microbes, and nutrient cycling, I combined greenhouse studies of plant physiology with field studies of soil processes to address questions that intersect biogeochemistry, ecosystem ecology, and restoration.
I worked at two research sites for my dissertation research. I examined the importance of plant functional diversity on the nitrogen cycle in the Stream and Wetland Assessment and Management Park (SWAMP) in Duke Forest, Durham, North Carolina. In a second project I studied the role of soil organic matter amendments in the development of soil properties and microbial activity in a restored wetland in Charlotte, N.C.
Duke Forest Biodiversity Site in July 2005. My biodiversity project combined a field study with a greenhouse study and my collaborator on this project was Justin Wright in the Duke Biology department. We measured plant traits in the greenhouse and then used those traits to calculate a measure of functional diversity to assess whether this measurement of diversity was more tightly linked to ecosystem functioning than the more traditional measure of diversity, species richness.
Duke Forest Biodiversity Site in September 2005. Our main findings from this experiment are that plant functional diversity significantly influenced denitrification potential through its interactions with soil conditions; increasing plant trait diversity led to increased denitrificaiton potential but mainly at higher soil resource levels(Sutton-Grier et al. (In review)). I presented these results at the Biodiversity and Restoration symposium at ESA, 2007.
Charlotte site in June 2004. At this site I examined how soil compost additions have affected soil properties and and microbial activity over three years since restoration. Based on my results from this study, compost can be used to increase soil macronutrients, specifically nitrogen and phosphorus, which can benefit plant growth. Compost amendments can also stimulate microbial activity since I found higher rates of denitrification in plots with more compost (Sutton-Grier et al. 2009).
Charlotte site in September 2004. I also found that, even though the Charlotte and Duke Forest sites differ in many respects, both sites have similar soil ecosystem structure meaning that similar soil variables and relationships between soil variables can be used to predict denitrification potential at both sites. This suggests there are fundamental relationships between soil properties and microbial functioning that persist even when restored wetlands have very different histories and soil conditions. However, a similar soil ecosystem structure did not guarantee similar ecosystem functioning at both sites (Sutton-Grier et al. 2010).
Duke Forest Restoration In Progress, 2005. I also had the opportunity to mentor a Master’s student, Josh Unghire, on a research project examining the impacts of restoration activities on soil properties that influence microbial nutrient cycling. We determined that restoration activities decreased soil organic matter levels while increasing phosphorus levels, and homogenized their spatial distributions. Four years post-restoration, there were fewer organic matter “hot spots” which are important for biogeochemical cycling suggesting that microbial processing of nutrients in the restored site could be limited by the disturbance and homogenization that occurred during restoration activities (Unghire et al., In revision). (Photo credit: M. Ho)
To read more about my doctoral research, please see my dissertation online.
References
1) Sutton-Grier, A.E. and J.P. Megonigal. (In preparation). Plant traits determine microbial competition and methane production in freshwater wetlands.
2)Sutton-Grier, A. E., J. Wright, and C. Richardon. (In review). Environmental conditions influence the plant functional diversity effect on denitrification potential.
3) Sutton-Grier, A. E., and C. Richardson. (2009). Organic amendments improve soil conditions and denitrification in a restored riparian wetland. Wetlands. 29:343-352.
4) Sutton-Grier, A. E., M. A. Kenney, and C. J. Richardson. 2010. Examining the relationship between ecosystem structure and function using structural equation modeling: A case study examining denitrification potential in restored wetlands. Ecological Modelling. 221:761-768.
5) Unghire, J., A.E. Sutton-Grier, N. Flanagan, and C. Richardson. (In revision). Investigating the spatial and quantitative impacts of stream restoration on riparian soil properties in the North Carolina Piedmont.
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