TEAM

Laura K Meredith, PI

Dr. Laura Meredith | PI. As an Associate Professor at the University of Arizona (UA), Dr. Meredith leads a research team focused on microbial trace gas metabolism, methods for sensing trace gases in soil, and scaling microbial processes driving biosphere-atmosphere exchange. Dr. Meredith received her PhD in 2013 from the Massachusetts Institute of Technology where her dissertation centered on the soil microbial sink for H2. As a NSF Postdoctoral Research Fellow at Stanford University she investigated the genomic underpinnings of microbial uptake of atmospheric carbonyl sulfide (OCS)—a promising carbon cycle tracer. Dr. Meredith joined the faculty of the University of Arizona in 2017 and has since built a research program recognized by NSF CAREER and AGU Thomas Hilker awards. As the Tropical Rainforest Science Director at Biosphere 2, she co-led the Water, Atmosphere, and Life Dynamics (WALD) campaign, a controlled ecosystem drought and rewet experiment focusing on VOC cycling. 

Dr. Meredith’s full BIO | CV | BlueSky | LinkedIn | laurameredith@arizona.edu

Research Team

Dr. Vanessa Buzzard | Senior Research Specialist. Dr. Buzzard received her Ph.D. from the University of Arizona in the Department of Ecology and Evolutionary Biology in 2017, where she focused on plant functional trait distributions across both space and time. Dr. Buzzard investigates natural and urban environments where she extends questions regarding the drivers of biodiversity and ecosystem function to the effects of green infrastructure water management on soils. Her research aims to quantify shifts in physical, chemical, and biological soil health indicators in response to green stormwater infrastructure in the City of Tucson. 

Dr. Juliana Gil LoaizaDr. Juliana Gil Loaiza | Research Specialist. Dr. Gil received her PhD from the Department of Soil, Water, and Environmental Sciences. As a researcher at the Meredith Lab in collaboration with Aerodyne Research Inc., she advances soil gas sampling approaches using nondestructive gas probes. Dr. Gil leads and supports research across the full breadth of our team’s work from H2 to VOCs and across lab experiments to field deployments. In particular she leads our efforts to understand interactions between soil H2 uptake and industrial H2 emissions. Diverse experiences motivate her to work on projects that foster the integration of academic research and private companies, to find synergistic answers to challenging environmental questions.  

Dr. Ian, Zhaoxin Zhang | Postdoc. Dr. Zhang focuses on how trace VOCs, produced by microbial, plant, and abiotic processes, enhance soil carbon storage. He received a Bachelor degree in Environmental Science from Zhejiang University, China, where he discovered his interest in the domain of microbial remediation on VOCs and pursued further interdisciplinary study. Dr. Zhang received his PhD in 2023 from the Hong Kong University of Science and Technology where his dissertation centered on the Allelopathic Potential of Microbial Volatile Emissions on Suppressing Malodor at Victoria Harbor.

After graduation, he would like to devote his energy to explore more globally from solving regionally environmental issues in Hong Kong to conclude and answer the internal principles of biogenic VOCs on soil carbon cycling. Now, he is conducting field and lab experiments to determine how plant productivity, root biomass, and plant growth stages influence soil carbon through VOCs-mediated processes in an agroecosystem of the bioenergy crop sorghum at the Maricopa Agricultural Center and contribute to field work at the Blodgett Forest Research Station in the Berkeley Lab to help determine the impact of deep soil warming on soil carbon in the coniferous forest. He works on integration of multi-omics datasets including volatilomics, metagenomics, proteomics and machine learning to help understand how BVOCs impact soil.

Dr. Vaishnavi Padaki | Moore Postdoctoral Fellow. Dr. Padaki received her PhD from Oregon State University, where she investigated VOC interactions between the diatom P. tricornutum and its phycosphere bacteria. During her studies at Oregon State, she focused on the mechanisms underlying VOC interactions between algae and bacteria and their effects on diatom physiology. After joining the Meredith Lab at the University of Arizona in August 2025, she became interested in expanding her VOC-centered mechanistic research to soil ecosystems and exploring VOC applications for real-world solutions. In our lab, she investigates how VOC mechanisms affect plant phenotype, yield, and productivity, as well as soil health, under Arizona’s arid conditions.

Dr. Jane Fudyma | NSF BIO Postdoctoral Fellow. Dr. Fudyma received her PhD from the University of California at Davis where she focused on soil viral communities and ecology. Jane’s postdoctoral research integrates soil microbial ecology, volatile organic compound (VOC) dynamics, and biogeochemistry in dryland ecosystems to use VOCs to illuminate plant-influenced microbial phenotypes in desert soils. 

 

Dr. Robert Bordelon | Postdoc. Dr. Bordelon focuses on ecosystem exchange and cycling of gases with the atmosphere from a variety of sources such as plants, soils, and water. He received his PhD from the University of Louisiana at Lafayette in Earth and Energy Sciences, where his research was primarily centered on the cycling and transport of carbon dioxide and methane in wetland systems. Since joining the Meredith Lab in 2026, his focus is currently on the ability of soil microbes to function as a sink of atmospheric hydrogen and how environmental controls may modulate this function depending on the ecosystem in question. Robert is driven by an urge to better understand the intersection of terrestrial, aquatic, and atmospheric systems, with emphasis on how interactions at these boundaries may vary in the face of an ever-changing global environment.

Parker GeffreParker Geffre | NSF Graduate Research Fellow and University Fellow.

Parker, a Tempe native, is a UA graduate with degrees in Biochemistry and Molecular Cellular Biology. At at the Meredith Lab, she currently works on VOC data analysis and synthesis, novel sensor testing, and various support roles depending on the project. Her research interests are at a crossroads of molecular biology and atmospheric chemistry. Parker focuses on linking VOC soil-atmosphere flux to microbial soil community composition and respective shifts through isotopic substrate labeling and low-cost VOC sensor development. As a NSF-GRFP fellow her primary project is focused on understanding the drought tolerance of soil microbes capable of degrading isoprene, the most abundant biogenic VOC on earth.

In her time at the Meredith Lab, she has worked directly with industry and international collaborators, specifically at Aerodyne Research, Inc. in Boston, MA and the Earth and Life Systems Alliance in Norwich, UK. Through her research, she seeks to help fill in knowledge gaps regarding the fate of VOC carbon. Parker also works to address the lack of accessible soil VOC data by compiling results from various studies to generate an open-access soil VOC database. Outside of research, Parker enjoys adventuring, studying British history, videogames, and drawing.

Alumni — postdocs and staff

  • Dr. Holly Andrews, NSF BIO Postdoctoral Fellow. Current position: Assistant Professor at Louisiana State University.
  • Dr. Linnea Hernandez (formerly Honeker), Postdoctoral Research Associate. Current position: Staff Scientist at Lawrence Livermore National Laboratory.
  • Dr. Gemma Purser, Postdoctoral Research Associate.
  • Dr. Qunli Shen, Postdoctoral Research Associate.
  • Dr. Alejandro Cueva, Postdoctoral Research Associate. Current position: Principal Investigator at El Colegio de la Frontera Sur, México.
  • Dr. Andreas Braændholt, Postdoctoral Research Associate. Current position: Assistant Professor at University of Copenhagen.
  • Dr. Kevin Webster, Postdoctoral Research Associate. Current position: Assistant Professor, Diné College, AZ.
  • Connor Youngerman, Research Specialist. Current position: Agroforestry and Mushroom Specialist, Cornell Small Farms Program

Alumni — graduate students

  • S. Marshall Ledford, PhD in Genetics (2026), University Fellow. Dissertation: “Volatile organic compound metabolism is an ancient and universal trait that rapidly emerges in developing ecosystems.” Current position: Postdoc at the University of Chicago.
  • C. Allison Newton, PhD in Natural Resources (2026). Dissertation: “Beyond Bare Soil: Vegetation and Microbial Drivers of Carbonyl Sulfide Fluxes in High-Latitude Ecosystems” Current position: Environmental Scientist II, Delaware Department of Natural Resources and Environmental Control Division of Air Quality.
  • Phoenix Spivey, MS in Natural Resources (2024), NSF BRIDGES Fellow, 2025 Outstanding SNRE Alumnus. Thesis: “Green infrastructures’ Impact: Urban Rainwater Garden Influences on Semi-Arid Soil Health.” Current position: Environmental Specialist II, North Carolina Department of Transportation.
  • Meara Clark, MS in Natural Resources (2023), NSF BRIDGES Fellow. Thesis: “The role of the HUC hydrogenase on the growth of Mycobacterium smegmatis under ambient and elevated hydrogen gas conditions.” 
  • Peter Moma, MS in Natural Resources (2021). Thesis: “Embracing complexity—hydrogen as a tool to unravel the spatial patterns of soil gas exchange.” 
  • Lia Crocker, MS in Biosystems Engineering, co-advised with primary advisor Jana U’Ren (2021). Thesis: “The composition and diversity of volatile organic compounds (VOCs) from leaf litter in the Biosphere 2 Tropical Rainforest.” Current position: Research Specialist, Biosphere 2 Ocean.
  • Harrison Friedman, MS in Natural Resources (2021), co-advised with primary advisor Rachel Gallery. “Sonoran Desert soil microbial community responses to changes in precipitation regime” Current position: Natural Resources and Planning, Bureau of Land Management.
  • Pablo Martínez-Sosa, PhD in Geosciences (2021) advised on microbiology research, advised by Jessica Tierney. Dissertation: “Branched GDGT response to oxygen and carbon availability in microcosms and mesocosms”. Current position: Postdoc at the  Geological Survey of Denmark and Greenland.
  • Carol Sayuri Nishisaka, MS visiting student from the Federal University of São Carlos, Brazil (2017) advised by Acacio Aparecido Navarrete.

Undergraduate, high school, and other contributors

  • Isabel Peck-Marmon – Undergraduate Researcher

  • Alexis Schwartzberg – Undergraduate Researcher

  • Skyler Good – Undergraduate Researcher

  • Taylor Weber – Biosphere 2 REU Intern (Pima Community College)

  • Maddie Sobieski – Undergraduate Researcher

  • Caroline Lasch – KEYS High School Intern

  • Brian Nguyen – KEYS High School Intern

  • Emily Huynh – KEYS High School Intern

  • Malcolm Barrios – KEYS High School Intern

  • Savannah Botello – KEYS High School Intern

  • Oliver Hoerth – Undergraduate Research (Honor’s College Exploratory Mini Grant Awardee)

  • Sushmita Marella – Undergraduate Research (Honor’s College Exploratory Mini Grant Awardee)

  • Surbhi Chandak – Undergraduate Research (Honor’s College Exploratory Mini Grant Awardee)

  • Mari Azulay – Undergraduate Research (Honor’s College Exploratory Mini Grant Awardee)

  • Cupid Nosewicz – Undergraduate Researcher

  • Phillipe Courdoson – Undergraduate Researcher

  • Beya Durazo – Undergraduate Researcher

  • Andrea Kirvaitis – Undergraduate Researcher

  • Josie Callahan-Santo – Undergraduate Researcher

  • Charlie Woodring – Undergraduate Researcher

  • Caroline Dias – Undergraduate Researcher

  • Adrian Castro – Undergraduate Researcher

  • Elizabeth Meek – Undergraduate Researcher

  • Woodrow Inness – Undergraduate Researcher

  • Renata Martin – Undergraduate Researcher

  • Bela Rein – Volunteer

  • Justin Grigory – UBRP Undergraduate Researcher (UA MCB)

  • Ryan Hunt – Undergraduate Researcher & Prior KEYS High School Intern (UA ENVS )

  • Kelsey Graves – Undergraduate Researcher (UA ENVS)

  • Margarita Henslee – UA ASEMS

  • Topanga Ronan – NSURP Intern (UC Davis)

  • Yasmine Lussier – KEYS High School Intern

  • Gina Ryu – KEYS High School Intern

  • Aleisha Lerma –  Biosphere 2 REU Intern (Northern Arizona University)

  • Kelly Rushford – KEYS High School Intern

  • Isabel Ross – KEYS High School Intern

  • Steven Persaud – NSURP Intern (Cornell University)

  • Rafael Viana Furer – NSURP Intern (Macalester College)

  • Elliana Laton – Undergraduate Research Assistant (Honors, UA)

  • Emily Espelage – Biosphere 2 REU Intern (Tacoma College)

  • Ashia Lujano – Biosphere 2 REU Intern (St. Cloud University)

  • Melissa Dong – Undergraduate Research Assistant (EEB, UA)

  • Michael Shulla – Undergraduate Research Assistant (EEB, UA)

  • Drew Sangerman – Undergraduate Research Assistant (SNRE, UA)

  • Michael Hughes – KEYS High School Intern

  • Halley Hughes – KEYS High School Intern

  • Jess Graham – Undergraduate Research Assistant (Honors, UA)

  • Sierra Frydenlund – Undergraduate Research Assistant (SNRE, UA)

  • Leslie Dominguez – Postbac Research Assistant (SNRE, UA)

  • Hannah Talkington – Undergraduate Research Assistant (SNRE, UA)

  • Michael Burman – Biosphere 2 Student Climber

  • Thor Neill – Biosphere 2 Student Climber

  • Sydney Kerman – Biosphere 2 Student Climber

  • Luke Miller – Biosphere 2 Student Climber

  • Marissa Clover – Undergraduate Research Assistant and Biosphere 2 Student Climber (BE, UA)

  • Dana Thorne – Undergraduate Research Assistant (EEB, UA)

  • David Hans Gieschen – Undergraduate Research Assistant (Environmental Science, UA)

  • Lucas Tate Montgomery – Undergraduate Research Assistant (Biochemistry, UA)

  • Jackie Larremore – Undergraduate Research Assistant (Microbiology, UA)

  • Fernando Diaz – Undergraduate Research Assistant (EEB, UA)

  • Erik Arcos – Undergraduate Research Assistant (Biosystems Engineering, UA)

  • Phoenix Spivey – Biosphere 2 REU Intern (North Carolina State University)

  • Jessica Pappas – Biosphere 2 REU Intern (University of San Francisco)

  • Gabriel Kellogg – UBRP NACEP Undergraduate Research Intern (Biochemistry, UA)

  • John Meraz – Biosphere 2 REU Intern (Arizona State University)

  • Ryan Hunt – KEYS High School Intern

  • Sara Te – KEYS High School Intern

  • Marilyn Mews – Undergraduate Research Assistant (Microbiology, UA)

  • Juliana Young – Honors College Research Intern (Molecular and Cellular Biology and Biochemistry, UA)

  • Joseph Guerrero – ASEMS Undergraduate Research Intern (BS Microbiology)

  • Saadat Malghani – Visiting Scholar
  • Evert Van-Schaik – Visiting Scholar