How do transformations at the microscale influence site and biome properties?
My research spans both permafrost and non-permafrost landscapes, with a focus on how heterogeneity unfolds across scales. I aim to understand how micro and meso-scale heterogeneity manifest at the landscape and biome levels.
The focus of my doctoral and postdoctoral research is Alaskan permafrost, however my graduate studies, training, and interests span semi-arid, desert, alpine, and wetland systems. I have studied in Svalbard, Norway, the Swiss and Italian Alps, as well as rainfed, semi-arid landscapes in Chilean Patagonia and Wyoming. I hope to continue my soil disturbance research in a variety of landscapes, examining soil transformations with attention to land use practices. I am interested in biogeochemical cycling and phosphorus availability, redox chemistry, physical soil structure and water movement, and landscape level comparisons of drivers of disturbance.
Recent Manuscripts
Pore2Chip: All-in-One Python Tool for Soil Microstructure Analysis and Micromodel Design
Pore2Chip is a Python package that generates 2-D micromodels from 3-D XCT images. This data includes characterization of the pore network via major metrics of water retention and flow (pore size distributions and pore throat size distributions) and connectivity (pore coordination numbers).
GitHub link coming soon!
Currently in prep for submission to JOSS.
Truong, A., M. Mudunuru, E.C. Rooney, A. Bhattacharjee, T. Varga, M.L. Mamud, X. He, A.K., Battu, S. Karra. Pore2Chip: All-in-One Python Tool for Soil Microstructure Analysis and Micromodel Design, in prep for submission to JOSS Summer 2024.
Free webinar on Wednesday June 12: Register Here.
Photo credit: Genoa Blankenship | Environmental Molecular Sciences Laboratory
Climate and ecosystem factors determine presence, frequency, and depth of soil freeze-thaw at the continental scale
Understanding how dynamic climate and soil properties influence FTC occurrence and frequency can help us predict soil, site, and biome response to changing climate patterns. Using climate and site property data from 40 National Ecological Observatory Network (NEON) sites, we quantified FTC frequency across soil depths, seasons, and ecosystem types. We grouped sites into (1) warm and wet (temperate rainforest, tropical seasonal forest/savanna, and temperate seasonal forest), (2) warm and dry (subtropical desert, woodland/shrubland, and temperate grassland/desert), and (3) cold and dry (tundra and boreal forest) climate groups based on site mean annual precipitation (MAP) and mean annual temperature (MAT). Site and soil properties, including MAT, MAP, maximum-minimum temperature difference, aridity index, precipitation as snow, and organic mat thickness, were used to both characterize climate groups and investigate site property relationships with FTC presence and amount.
E.C. Rooney & A.R. Possinger, in review with JGR Biogeosciences.
Topography and canopy cover influence soil carbon composition and distribution across a forested hillslope in the discontinuous permafrost zone
Soil temperature varies as a function of canopy cover, with warmer soil temperatures occurring under open cover as a function of winter snow insulation on summer radiation. Using FT-ICR-MS coupled with soil characterization, we identified how SOM composition varied across a forested hillslope in Fairbanks, Alaska under open and closed canopy cover.
Rooney, EC, Bailey, VL, Patel, KF, Kholodov, A, Golightly, H, Lybrand, RA. Topography and canopy cover influence soil organic carbon composition and distribution across a forested hillslope in the discontinuous permafrost zone. Permafrost and Periglac Process. 2023; 1- 28. doi: 10.1002/ppp.2200
Rooney E (2023): Topography and canopy cover influence soil organic carbon composition and distribution across a forested hillslope in the discontinuous permafrost zone. Soil Carbon Biogeochemistry, ESS-DIVE repository. Dataset. doi:10.15485/1988078
Illustration credit: ©2023 The Regents of the University of California, Davis campus. All rights reserved. Artist: Robin Riedel.
In collaboration with EMSL and BSD scientists at PNNL, we used NEON sampled soils from two sites in Alaska with contrasting environmental histories (Healy - high frequency of freeze-thaw cycles, Toolik - low frequency of freeze-thaw cycles) to address our hypothesis. We used Fourier-transform ion cyclotron resonance to probe the effects of site, depth, and experimental freeze-thaw on the nominal oxidation state of carbon (NOSC), hydrogen and oxygen saturation, and the relative abundances of aliphatic, aromatic, condensed aromatic, and lignin-like compounds.
Rooney, E.C., et al. (2022). The impact of freeze-thaw history on soil carbon response to experimental freeze-thaw cycles. JGR Biogeosciences, Volume 125, Issue 5. https://doi.org/10.1029/2022JG006889
Rooney, E (2022): The impact of freeze-thaw history on soil carbon response to experimental freeze-thaw cycles. Soil Carbon Biogeochemistry. ESS-DIVE repository. doi:10.15485/1868940.
This research aims to provide a pore-scale perspective on changes to the pore network occurring at this incipient stage of permafrost warming, specifically within the first five freeze-thaw cycles following thaw. We collaborated with EMSL and BSD scientists at PNNL and NEON scientists to contribute to the current understanding of freeze-thaw deformation while providing data needed for future predictions of how climate warming will alter the physical properties of globally important Arctic landscapes.
We found changes in pore connectivity and volumetric fractions following six freeze-thaw cycles. In the figure A (left panel) = before freeze-thaw and B (right panel) = after freeze-thaw.
Rooney E.C., et al. (2022). Soil pore network response to freeze-thaw cycles in permafrost aggregates. Geoderma. https://doi.org/10.1016/j.geoderma.2021.115674
Rooney E (2022): Soil pore network response to freeze-thaw cycles in permafrost aggregates. Soil Carbon Biogeochemistry, ESS-DIVE repository. Dataset. doi:10.15485/1838886
Mineral and organic matter associated phosphorus in soils of winter wheat (Triticum aestivum, L.) and cover crop systems
Dryland winter wheat (Triticum aestivum L.) producers in the Northern High Plains ecoregion of the United Stated navigate soils with low moisture and high calcium carbonate (CaCO3) content. These conditions curb plant available phosphorus, reducing wheat yields and post-harvest crop residue returns. A single application of compost at a high rate ( 50 Mg ha-1) can produce lasting positive effects on wheat yield, biomass production, and overall nutrient availability. We conducted greenhouse and incubation studies to evaluate how soil and winter wheat responded to a one-time high-rate compost application followed by cover crop rotations.
In preparation for submission to Nutrient Cycling in Agroecosystems.