TEAM

Dr. Laura Meredith

Dr. Laura Meredith | PI

Dr. Laura Meredith is an assistant professor at the University of Arizona (UA) where she 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 overwhelming 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 supported by grants including the prestigious NSF CAREER award. As the Tropical Rainforest Science Director at Biosphere 2, she recently 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 | Twitter | laurameredith@arizona.edu

Dr Vanessa Buzzard

Dr. Vanessa Buzzard | Senior Research Specialist

Dr. Buzzard is a senior research specialist with Dr. Meredith in the School of Natural Resources and the Environment. She 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. She has since moved from studies of predominantly natural systems to focus on urban environments, where she extends questions regarding the drivers of biodiversity and ecosystem function to the effects of green infrastructure water management on soils in urban environments. 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 Loaiza

Dr. Juliana Gil Loaiza | Research Specialist

Juliana earned a B.S. in industrial microbiology in Bogotá, Colombia. As a researcher at the Meredith Lab in collaboration with Aerodyne Research Inc., she studies spatial resolution of microbial activity, integrating new soil probes with laser spectrometers for trace gases and their isotopic fingerprints in soil. Her scope of work includes: scaling up the application of the integrated system from lab columns, to an enclosed tropical rainforest at Biosphere 2, to an agroecosystem at the Maricopa Agricultural Center, measuring a wide diverse array of gases to study VOC and nitrogen cycling in soil.  

Diverse experiences—in environmental microbiology and as an environmental consultant— motivate her to work on projects that foster the integration of academic research with the pragmatic concerns of private companies, to find synergistic answers to challenging environmental questions. Moving from the Andes to the Sonoran desert to pursue a doctoral degree in environmental science at the University of Arizona, Juliana gained experience in fieldwork, bench-scale work, and community outreach as a Superfund research program trainee by studying revegetation of legacy mine tailings. Juliana is inspired to utilize her bench-work research to more deeply understand the interactions of environmental parameters in the field and practical applications.

Dr. Seven, Qunli Shen | Postdoc, DOE-GSP

Originally hailing from China, Qunli Shen (English name Seven) received his Ph.D. in Soil Science from Zhejiang University in 2021. His diverse research interests encompass soil health, greenhouse gas emissions, carbon and nitrogen cycling, waste management, soil microbial ecology, and molecular biology. During his Ph.D., the primary thrust of his research was dedicated to unraveling the intricacies of soil nitrogen cycling and microbial ecology. Additionally, he collaborated with Dr. Paul Voroney at the University of Guelph, delving into the realm of soil carbon (C) cycling.

Qunli Shen is now a postdoctoral fellow at Lawrence Berkeley National Lab and the University of Arizona, collaborating with Dr. Laura Meredith and Dr. Kolby Jardine. His ongoing research is centered on exploring the impact of drought stress on soil VOC cycling and soil C cycling. Leveraging omic techniques such as metagenomics, metatranscriptomics, volatilomics, and metabolomics, he aims to elucidate the intricate relationships between soil microbes, related genes, and the targeted processes

Dr. Ian, Zhaoxin Zhang | Postdoc, DOE-GSP

Ian, Zhaoxin Zhang, is a Postdoctoral Researcher in Meredith lab where he mainly 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.

C. Allison Newton

C. Allison Newton | PhD Student, SNRE

Allison started her academic career at Salisbury University (MD) earning a Bachelor of Science in Chemistry. After developing an interest in analytical chemistry and instrumentation, she moved on to Towson University (MD) where she earned a Master of Science in Forensic Science (trace analysis focus). While at Towson, her work focused on the identification of volatile organic compounds (VOC). After experiencing graduate level research and its impacts, Allison decided to pursue a PhD. She began this journey in the Chemistry department at the University of Arizona. Here, she earned a Master of Art in Chemistry (analytical focus), before moving on to her current lab in the School of Natural Resources. In the Meredith lab she works on the development of carbonyl sulfide (OCS) as a carbon cycle tracer.

S. Marshall Ledford

S. Marshall Ledford | PhD Student, Genetics

Marshall is a doctoral student in the Genetics Graduate Interdisciplinary Program and a University Fellow. Originally from the Appalachian Mountains in North Georgia, he graduated from Vassar College with a B.A. in general biology. There, his research focused on analyzing post-translational modifiers in response to heat stress within a model moss species. Through experience working with NASA Ames, the Mars Society, and the American Society for Gravitational and Space Research, he has developed a strong passion for space research and astrobiology. In the Meredith lab, he is currently exploring the possibility of using soil gas fluxes as a method for life detection, with an emphasis on understanding the influence of environmental factors on microbial-gas interactions. Eventually, he hopes to incorporate how these might relate to biosignatures in extreme soil environments on Earth and elsewhere.

Phoenix Spivey | MS Student, SNRE

Phoenix Spivey is native to Louisburg, North Carolina, where her interest in all things environmental developed. She graduated from North Carolina State University with a B.S in Environmental Science and minors in applied ecology and biological science. During her undergraduate years, she completed an REU with the University of Arizona at Biosphere 2, where she studied the rainwater microbial composition of the Landscape Evolution Observatory. After obtaining her bachelor’s, she worked in the conservation world supporting and conducting research related to blue carbon, water quality, and sea turtle indexes within barrier island ecosystems on the coast of North Carolina. The interdisciplinary work she conducted inspired her to pursue an M.S in Natural Resource Studies here at the University of Arizona. As a NSF BRIDGES Fellow, she plans explore her interests in biomonitoring techniques to improve and support biogeochemical cycles, ecosystem health, sustainable/equitable infrastructure, and community resilience. In her free time, Phoenix loves to hike, collect rocks, and listen to quirky music playlists and podcasts on Spotify

Parker Geffre | Research Technician I

Parker, a Tempe native, is a UA graduate with degrees in Biochemistry and Molecular Cellular Biology. As a research technician 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. 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.

Group photos

Former group members and visitors

Graduate students, postdocs, and researchers

  • Linnea Honeker – Biosphere 2 Postdoc (current position: researcher at Lawrence Livermore National Laboratory)
  • Holly Andrews – Postdoc (current position: postdoc at University of Arizona) (NSF Postdoctoral Fellow)
  • Meara Clark – UA SNRE MS Graduate (NSF BRIDGES)
  • Peter Moma – UA SNRE MS Graduate
  • Connor Youngerman – Research Specialist
  • Alejandro (Alex) Cueva – Biosphere 2 Postdoc (current position: postdoc at Arizona State University, AZ)
  • Andreas Braændholt – Postdoc (current position: postdoc at University of Arizona)
  • Kevin Webster – Postdoc (current position: Assistant Professor, Diné College, AZ)
  • Carol Sayuri Nishisaka – Visiting Masters Student (Federal University of São Carlos, Brazil)

Undergraduate and high school researchers

  • 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, UA)