Malak M. Tfaily
Primary Investigator | Assistant Professor
Malak is an ecosystem scientist with a PhD degree in Analytical chemistry from Florida State University. Her research aims to improve the understanding of carbon cycling in terrestrial and aquatic systems, the microbial-organic matter interactions that underlie it, and the controls upon it in dynamically changing systems. She uses a combination of modern and unique analytical molecular, geochemical and isotopic techniques to answer how, where and when organic matter formation and degradation takes place in different ecosystems. Malak’s research training focused on dissolved organic matter characterization during her PhD, soil organic matter characterization during her postdoctoral research, and recently has advanced to the systems-level integration of detailed organic matter characterization with insights from molecular microbial ecology and plant biology, with the direct goal of distilling the findings of these syntheses for improved predictive modeling of ecosystem and global change.
Current lab members
Moira Hough– Postdoctoral Researcher | ENVS | EEB
Linnea Katherine Honeker-Postdoctoral Researcher | Biosphere2 | SNRE | ENVS
Linnea Honeker, originally from Chicago, Illinois and transplanted to Tucson, AZ in high school, received her B.S. in Ecology and Evolutionary Biology at University of Arizona in 2001. After graduation, she discovered her love for Microbial Ecology while working for an aquarium company in Los Angelas, CA where she studied ammonia- and nitrite-oxidizing bacteria to be used to prevent ‘new tank syndrome’ in fish tanks. With this new-found love, she returned to graduate school to study the role of microbes in plant health and metal(loid) cycling during revegetation of toxic mine tailings, and she received her PhD in Environmental Science from the University of Arizona in 2017. Next, she went on to her first post-doc in the Department of Molecular Medicine at the University of Arizona with Dr. Donata Vercelli to study the role of the gut microbiome and microbially-produced metabolites in protection from asthma. Linnea is now in her second postdoc with Dr. Tfaily and Dr. Meredith where she studies the effect of drought on the soil microbial ecology of the tropical rainforest and Biosphere 2. She works on integration of multi-omics datasets including metagenomics, metatranscriptomics, volatilomics, and metabolomics to help understand how drought impacts soil microbial activity and metabolic pathways.
Roya AminiTabrizi- Graduate Student | ENVS
Roya is from Urmia, a city in northwest Iran. She received her bachelor’s degree in pure chemistry from Sharif University of Technology, Tehran, Iran on July 2016. In January 2017, she moved to Edwardsville, Illinois and started a master’s study in Analytical chemistry at Southern Illinois University Edwardsville. She graduated on July 2018 and moved to Tucson, Az to start the Analytical chemistry PhD program at the University of Arizona. Currently, Roya is doing her PhD in Soil, Water and Environmental Science with a minor in Analytical chemistry. Roya’s research in Dr. Tfaily’s lab revolves around carbon cycling in terrestrial and aquatic ecosystems, the interactions between microbial communities and organic matter, their geochemical environment and the resulting impact on the whole ecosystem. She uses a combination of modern analytical molecular techniques (high resolution mass spectrometry), geochemical (wet chemistry and gas flux) and isotopic techniques (natural abundance, and isotope enrichment) to answer the how, where and how organic matter degradation and formation takes place in different ecosystems. Her work examines the direct relationship between organic matter composition, the activity of the biological community, the geochemical signature of the activity and how that signature may translate between environments thus enhancing our understanding of the current and past processes that drive our planet. Her main research site is a permafrost site in Northern Sweden. In addition to characterizing organic matter composition at this site, she is looking at exploring new ways, methods and approaches to characterize unknown metabolites by Liquid chromatography mass spectrometry.
Viviana Estefania Freire Zapata– Graduate Student | ENVS
Viviana “Vivi” Freire Zapata is a Biotechnology engineer, originally from Ecuador. Viviana’s career path started in 2017 when she joined the Department of Entomology and Plant pathology at Oklahoma State University (OSU) as a research scholar. During that time, she worked with soil-borne fungi and oomycetes, focusing on molecular identification and population structure analysis using single sequence repeats (SSRs). After that, she had the opportunity to work at the Institute of Biosecurity and Microbial Forensics in the same university. She worked on the molecular identification of viruses and bacteria infecting grapevine. As part of this project, she gained hands-on experience with next generation sequencing using Oxford Nanopore Technologies’ MinION. Having a profound interest in molecular biology (DNA and RNA) and microbes, Viviana pursed a master’s degree in Plant Pathology in Oklahoma State University. Viviana’s master project was related with a phenomenon called fungicide hormesis, studying how low doses of stressors (e.g., fungicides), cause stimulatory effects, on fungal traits such as growth or virulence instead of inhibition. This project led her to get involved with designing and performing of transcriptomics analysis while developing coding skills, something which she enjoys and keeps improving nowadays. Viviana’s interest on microbes and the use of omics data led her to join the Tfaily’s lab in January 2021. Currently, she is a doctoral student at the Department of Environmental Sciences at the University of Arizona. Her research interests focus on understanding biotic (microbes and plants) and abiotic interactions happening in the ecosystems as a response to disturbance and/or stress. She is interested on the integration of multi-omics data (genomic, transcriptomics and metabolomics) to analyze the underlying biogeochemical processes taking place in ecosystems such as arid soils and thawing permafrost peatlands.
Christian Orlando Ayala Ortiz– Graduate Student | ENVS
Christian Ayala was born and raised in Quito, Ecuador where he obtained his B.S. in Biotechnology Engineering at the Universidad de las Fuerzas Armadas-ESPE in 2016. After working for a year, he got accepted into graduate school and traveled to the US to be a master student in the Department of Entomology and Plant Pathology at Oklahoma State University. His research involved sequencing and assembling genomes and transcriptomes of several leafhopper species to look into the genomic determinants of vector competence. It was at this time, that Christian found out that he truly enjoyed working with omics data and that moving forward he would like to learn more about bioinformatics and data analysis. After earning his master’s degree Christian remained at Oklahoma State University as a research scientist for a year, working in several insect-related multi-omics projects, including analyzing the effect of diet in the gene expression of burying beetles and using ONT’s long read sequencing techniques to study RNA modifications in the honeybee. Working on these projects allowed him to improve his programming skills. In January 2021, he joined the Tfaily lab at the University of Arizona as a doctoral student in Environmental Science. His research interests include: the development of streamlined and user-friendly pipelines for the analysis and integration of complex and heterogenous multi-omics dataset; and the application of such methods to better understand the how microbial communities respond to changes in resource availability and the effects of this response in the complex interactions happening in the ecosystem.
Ghiwa Makke- Graduate Student | ENVS
Ghiwa is from Lebanon. She received a B.S. in Biology from Lebanese American University in 2016. In 2019 she received her master’s degree in Molecular Biology with an emphasis on microbial genetics from the Lebanese American University. Currently, Ghiwa is doing her PhD in Environmental Science at the University of Arizona. Ghiwa’s research in Tfaily Lab will revolve around understanding the relationship between microbial community composition, their metabolic activity, and the effect of environmental change on organic matter. She will also address the biotic effect (microbial life, non-vascular and vascular plant life) on hydrology and geochemistry. Her research will use a full “omics” approach to understand gene to ecosystem functioning.
Megan Neol Nickerson- Graduate Student | ENVS
Megan was born and raised in Tucson, Arizona, and graduated with a BS in microbiology and a minor in biochemistry from the UArizona Honors College in May 2021. She began work toward a PhD in environmental science in Fall 2021 with co-advisors Dr. Malak Tfaily and Dr. Jana U’Ren. Her primary research interest is in the intersection between endophytic fungi and the chemical environment of their hosts. Her research centers on using metabolomics, genomics, and molecular biology to identify the genetic basis for microbial functional traits. She hopes to then use this knowledge to better understand patterns of microbial community assembly, biodiversity, nutrient cycling, and ecosystem function. She is currently being funded by the BRIDGES NRT fellowship.
Gina Ann Hildebrand – Masters Student | ENVS
Gina Hildebrand, originally from Phoenix, Arizona, received her B.A. in Art History at Arizona State University in 2014. During her undergrad she hoped to use her degree to find, preserve, and restore cultural artifacts, work in museums, and unearth the secrets of ancient peoples. Yet, as she traveled and learned more about how anthropological affairs were impacting the world, she decided that preserving the Earth was of the upmost importance. She then matriculated to the University of Arizona in 2020 to start her master’s degree in Environmental Science. Gina is now in her second year in Dr. Tfaily’s lab where her research is centered around soil interactions at Biosphere’s 2 tropical rainforest. At this study site, a three-month drought experiment was conducted to study carbon organic matter response in terrestrial systems. Her thesis focuses on how water scarcity will change the composition of soil, ecological interactions, and nutrient cycling, especially in terms of future land use and the compounding effects of climate change. When she’s not working in the lab, she spends as much time as possible in her hammock, propagating plants, hiking, traveling, and going on adventures.
Taylor Portman- Masters Student | ENVS
Taylor received her B.S. in biochemistry at the University of New Mexico where she completed a senior thesis project investigating plant-fungal symbiosis on lands impacted by Uranium mining legacy. As an M.S. student in the Tfaily lab, she will continue to investigate plant-microbe interactions by utilizing analytical chemistry methods to uncover how microbially mediated shifts in soil chemistry are impacting plant turnover. She is interested in the impacts of plant-fungal interactions on soil chemistry, and how global change will impact plant-microbe-mediated pathways and biogeochemical cycling. Her current research site is the Santa Rita Experimental Range, where she is conducting experiments involving the invasive grass species Eragrostis lehmanniana (Lehman’s lovegrass). Taylor is co-advised by Dr. Malak Tfaily and Dr. Betsy Arnold, she is a recipient of the BRIDGES NRT fellowship, and in addition to her research is passionate about mentorship, policy, and science communication.
Rylie Gosiak – Masters Student | ENVS
Rylie grew up in Maricopa, AZ and has been at U of A for three years. She will be entering the Environmental Science accelerated masters program in the Fall of 2020. Rylie has always been interested in the environment because she enjoys being outside and feels passionate about protecting our planet. After completing her masters, she would like to go into the Hydrology field. In her spare time she enjoys watching Netflix, spending time with her family, and hanging out with friends. Rylie is working on the Critical Zone Observatory (CZO) project, where she is helping characterize organic matter through different watershed sites. She also takes part in extractions, data analysis, and contributing to the overall fun morale of the lab.
Anna Jones- – Masters Student | ENVS
Anna was born and raised in Toledo, Ohio and is majoring in environmental science. She fell in love with research while helping grad students on nectar quality research in the Oak Openings area. On campus, Anna is a part of the Honors College and enjoys going to the university’s sports games. She also loves to hike, travel, and binge watch television shows. In the Tfaily lab, Anna helps with soil core processing, freeze drying samples, and SPE. She will begin an incubation experiment measuring gas fluxes and organic matter changes with Tyler this semester
Tyler Rodshagen – Masters Student | ENVS
Tyler is a sophomore from Seattle, Washington majoring in environmental engineering. His love for the environment stems from outdoor activities like hiking, skiing, and rock climbing. In his free time, Tyler enjoys exercising, cooking, and watching TV shows. In the future, he hopes to study abroad in Denmark, working with renewable energy systems or oceanic ecosystems.
This semester, Tyler will be working on an incubation experiment with Anna, measuring the production of methane by methanogens under a mix of different temperature and substrate treatments of peatland soil.
Paris Clare Stegall – Masters Student | ENVS
Kelly Nicole Rushford- Undergraduate Student | ENVS
Rushford is a sophomore pursuing a BS in Environmental Science with an emphasis in Sustainability, Communication, and Leadership and a minor in Spanish. She got involved in the Tfaily lab through the KEYS (Keep Engaging Youth in Science) research internship where she studied the metabolome of peatland soils under the mentorship of Dr. Laura Meredith. She is continuing her investigation of the ecological response of peatlands to climate change with the SPRUCE project. Her interests intersect environmental science and community resilience, ranging from ecological restoration to citizen science.
Research specialist/Lab manager
Jane was born in New York City, but was swiftly uprooted and raised in Salt Lake City, UT on skiing and outdoors adventures. In 2013 she received a B.S. with honors in General Science, Biology and Chemistry concentrations, and a minor in studio art from Seattle University. She returned to Salt Lake and spent five years working for Inotec, a biotechnology company that uses bacteria to treat and remove inorganics/pollutants from mining waste. Her dual interest in environmental chemistry and microbiology, as well as her last two years at Inotec as a lab manager, landed her a position as a research specialist and lab manager for the Tfaily lab. When Jane is not working in the lab/field you can find her road tripping to ski in Flagstaff, hiking, rock climbing, and in general being outside.
Jane is involved in two major research projects in the Tfaily lab, a rainforest ecology project at Biosphere 2 and a peatland ecology project in Minnesota. Both projects focus on organic matter transformation and degradation in terrestrial and aquatic ecosystems, the abiotic and microbial interactions that underlay these organic matter transformations, and implications of climate impact. She is also interested in how viruses impact the soil microbe-organic matter nexus and what triggers viruses to control organic matter changes and microbial responses in various systems. Her research uses a full “omics” approach to understand gene to ecosystem functioning, including analytical molecular, microbiological, geochemical, and isotopic techniques. Jane also oversees independent study student projects and all ongoing laboratory projects.
Nathalia Graf Grachet
Nathalia is originally from Brazil. She received a B.S. in Agricultural Engineering, and her interests in plant diseases started in her sophomore year when she joined the plant pathology lab. She moved to Stillwater, Oklahoma in 2013 to attend graduate school at Oklahoma State University. She received her M.S. in Entomology and Plant Pathology in 2015 studying the effect of foliar fungicide application on chlorophyll content and yield winter wheat varieties. In August 2019, she received her Ph.D. in Plant Pathology studying plant-pathogen interactions of bermudagrass and the soil-borne fungal pathogens of spring dead spot. Nathalia’s research interests broadened when she attended two computational biology courses at Cold Spring Harbor Laboratory in 2017 and 2018. She learned the basics of Python programming and bioinformatics, and fell in love! She became a certified instructor for the Software and Data Carpentry in the Fall of 2018, and have taught campus-wide workshops in a variety of topics including Python and Unix command line.
Nathalia joined the Tfaily lab in October 2019. Currently, she is developing data analysis pipelines for a variety of research projects in the Tfaily lab, including soil organic matter composition and microbial community of the tropical rainforest at Biosphere 2. She will be developing her our research projects pretty soon. She will apply the modern techniques used in Tfaily’s lab to agricultural systems. She will research the role agricultural management practices play in the microbiome in the soil and in the plant, and how those practices affect soil organic matter degradation and formation.
Undergraduate Student | ENVS
Please allow us to introduce our youngest team member, Hans Gieschen. Hans was born and raised in San Diego, California before coming to the University of Arizona to pursue a degree in Environmental Science. Hans’s love for science started at a young age when he got his first pet frog. Since then, Hans has always had a deep interest in science, animals, and the environment. In the future, Hans would like to travel to the rain forest and conduct research in Spanish speaking countries. Outside of work, some of his interests include basketball, and his fraternity. Hans is a die hard Los Angeles Clippers fan, and is very involved in the Delta Beta chapter of Beta Theta Pi, recently serving as President of Philanthropy.
Hans’ research in the Tfaily lab is centered around comparing abiotic/biotic controls on organic matter degradation and transformation via mass spec data analysis. He is also involved in the B2 rainforest project that focuses on gene to ecosystem organic matter fluxes and transformation.
Undergraduate Student | ENVS & SPS
Jamee is a junior, originally from the suburbs outside of Chicago, majoring in Sustainable Plant Systems with an emphasis in Environmental Horticulture. This program comes from both The School of Plant Sciences and The School of Soil Water and Environmental Sciences. After graduating from the University of Arizona, Jamee plans to attend a five-year graduate program at the Southwest College of Naturopathic Medicine in Tempe, Arizona to become a Naturopathic Doctor. In Dr. Tfaily’s lab, she is comparing properties between selected medicinal plants and Sphagnum, a dominating moss in the Northern peatland. Through extraction and with the mass spectrometer, she analyzes the organic compounds and antimicrobial nature of Sphagnum moss and selected medicinal plants.
Undergraduate Student | SNRE
Halley Hughes was born and raised in Tucson, Arizona. She will attend the University Arizona Honors College in the fall. Halley plans to major in Natural Resources and the Environment with a minor in French. Halley’s love for the environment grew from many hiking adventures and a very passionate biology teacher. She is an avid gardener and has since become very invested in sustainable agriculture.
As part of Dr. Tfaily’s lab, Halley will be performing soil organic matter extractions relating to the tropical rainforest at the Biosphere 2, and helping with incubation experiments to study the effect of temperature on soil organic matter transformations.
Undergraduate Student | ENGR
Hannah was born in Mesa, Arizona and is currently a freshman majoring in Environmental Engineering. Her interest for the environment was initially sparked by her mother’s work for Arizona State University’s sustainability department. She decided to follow an Environmental Engineering route in order to develop more renewable systems and technologies that will contribute to a more sustainable world. Aside from research, Hannah enjoys cooking, binge watching shows, outdoor activities, and traveling. She is looking forward to traveling to Europe for the first time this summer! In the future, she hopes to travel so that she may help implement more sustainable means of technology in developing countries.