User:Dawson Fairbanks

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Contact Info

Dawson Fairbanks

• Dawson Fairbanks
• University of Arizona
• Saguaro Hall 315
• Tucson, AZ
• dawsonfairbanks{at}email.arizona.edu

Education

• 2014-present, Ph.D Soil, Water, Environmental Science, University of Arizona
• 2012, B.S. Biological Sciences, Northern Arizona University

Research Interests

• Stable Isotope Analysis
• Environmental Microbiology
• Soil Science
• Global Change
• Ecosystem Ecology
• Landscape Evolution

About

My research career began after taking the course Ecosystem Ecology with Nancy Johnson and Bruce Hungate at Northern Arizona University. I was fascinated by the advances in the field and the process of discovery and I knew I had to be involved. The proposal I wrote for the course I submitted to Hooper Undergraduate Research Award and received funding for $3,500 to carry out my own independent research project advised by Catherine Gehring. I joined the Mycorrhizal Ecology Lab as a research technician and I assisted in greenhouse, field, and laboratory research experiments studying how biotic and abiotic forces in the environment affect mycorrhizal populations and communities, and how these changes in turn influence host plant performance. The experiment I designed tested the hypothesis that exotic Russian Olive could outcompete native Fremont Cottonwoods in soils impacted by Tamarisk based on the findings that Tamarisk had been shown to disrupt mycorrhizal mutualisms of native species Cottonwoods and Willows. I conducted a greenhouse study planting Cottonwood and Russian Olive seedlings in live and sterilized soil collected from a Tamarisk stand. I then analyzed root tips using clearing and staining techniques to quantify percent mycorrhizal colonization in both plant species and compared fungal colonization to relative growth and success of each plant species. Tamarisk was shown to increase potentially pathogenic fungal colonization in both plant species where Russian Olive seedlings exhibited a greater negative effect in terms of relative growth. These findings were presented at the May 2013 Hooper Undergraduate Research Award Symposium and the NAU Undergraduate Research Symposium.

During this time I also began working in the Center for Ecosystem Science and Society Group advised by Dr. Paul Dijkstra studying biochemical processes of soil and hot spring microbial communities using newly developed stable isotope techniques. From incubation experiments conducted on whole living soils, we were able to calculate the Carbon Use Efficiency using position-specific stable isotope pairs to calculate the central carbon metabolic network including glycolysis, TCA cycle, and pentose phosphate pathways. The metabolic model was solved using the ratio of CO₂ production from 1-¹³C and from U-¹³C glucose and from 1-¹³C and 2,3-¹³C pyruvate. To evaluate the model we incorporated additional isotopomers of glucose and the model then calculated the ratio of ¹³CO₂ production from the remaining C-atoms of glucose relative to U-¹³C glucose. These modeled values for glucose isotopomers were compared with measured glucose isotopomer ratios. By measuring the reaction rate at which ¹³CO₂ is released we calculated how much carbon is respired into the atmosphere vs. incorporated into microbial biomass and biosynthetic precursors. These findings were presented at the December 2012 AGU conference in San Francisco.

Now, I am continuing my research investigating C cycling in soils at the Critical Zone Observatories located in the Jemez River Basin in New Mexico and the Santa Catalina Mountains near Tucson. My dissertation project is largely interdisciplinary working with modelers, biogeochemists, hydrologists, and geologists with the goal of understanding the functional role of microorganisms and to identify physiological responses to soil in relation to changing environmental conditions and climates. To do this we will utilize a metadata-rich and model-supported systems context to examine all three domains of fungal, bacterial, and archaeal communities targeting changes in relative abundances of specific taxa or functional groups through a host of meta-omic (-genomic, -transcriptomic, and -proteomic) techniques and enzyme assay analysis to gain an overall understanding into functional processes underlying carbon storage and release and the role of disturbance in landscape evolution processes.

Current Projects

Microbiology in the Critical Zone: geomicrobiology, "hot spots and hot moments", and ecosystem services in the JRB-SCM CZO

The JRB-SCM Critical Zone Observatory is an interdisciplinary observatory that will improve our fundamental understanding of the function, structure and co-evolution of vegetation, soils, and landforms that comprise the Critical Zone (CZ). This CZO lead by Jon Chorover has developed a conceptual framework of (a) “hot spots and hot moments”, where landscape change occurs non-uniformly over space and time, for example occurring rapidly after major fire events (which our CZO just experienced in summer 2013), and (b) an energy/carbon flow equation ("EEMT", effective energy and mass transfer, developed by CZO PI Craig Rasmussen) that quantitatively describes critical zone landscape evolution. With the recent summer 2013 renewal the SWES-MEL lab and the Gallery Lab have begun to bridge microbiology and CZO biogeochemistry in the context of water and soil processes, including decomposition, weathering, carbon stabilization, and carbon flow, and water purification. Our approach spans both physiological (Gallery Lab) and meta-omic (Rich lab) approaches.

Outreach and Education

Women in Science and Engineering (WISE) WISE offers a wide range of programs for both students and professionals, including a conference for middle and high school students, academic and career preparation programs for college students, mentoring, internships, scholarships, a living-learning residential community, and much more. I have participated in leading workshop events and encouraging STEM education in high school and middle school students

UA i-STEM Project The UA i-STEM project is currently working with over 30 3rd-8th grade students in a program that combines one-on-one mentoring with science and engineering exploration in two Tucson area schools. In the summer of 2012, the NSF funded, i-STEM Project, was launched with the goal of designing, implementing and evaluating an innovative model for engaging underrepresented students, specifically Native Americans and Hispanic youth, in science, technology, engineering and math. I have participated in the mentoring program where we do flash STEM activities with middle school students (lasting about a half hour to an hour) and then participate in field outings to encourage STEM education in underrepresented youth.

GPSC Award Judge The Graduate and Professional Student Council (GPSC) was created to promote the causes and concerns of the graduate student body, to create and foster programs beneficial for growth and interaction, to disburse funds for the benefit of professional development, and to serve as the representative body and voice at the University of Arizona. I have participated in judging financial award requests for travel grants.

EarthWeek and SWESx Graduate Student Representative The School of Earth & Environmental Sciences hosts Earth week at UA every year. As a Soil, Water and Environmental Science (SWES) departmental graduate student representative, I am responsible for organizing the event and recruiting students in the SWES department for presentations, reviewing abstract and poster submissions as well as assisting in logistical planning.

Sierra Club Youth Outdoors Volunteer Sierra Club Inner City Outings (ICO) is a community outreach program that provides opportunities for urban youth and adults to explore, enjoy and protect the natural world. ICO is dedicated to providing outdoor opportunities to people that would not otherwise have them, including low-income youth of diverse cultural and ethnic backgrounds. I volunteer as a leader to help organize outdoor adventures including hiking, camping, kayaking and mountain biking for people of all ages and disabilities. We teach participants introduced to the wilderness the Sierra Club values and how to tread lightly by using Leave No Trace ethics.

Presentations

• Fairbanks, Dawson, Erin Miller, Elena Salpas, Shannon Hagerty, Bruce Hungate, Jane Marks, George Koch, Egbert Schwartz, Scott Thomas, Brian Hedlund and Paul Dijkstra. Measuring and modeling activities of the central carbon metabolic processes using position-specific ¹³C-labeled metabolic tracers in soil and hot spring microbial communities. (2013). Poster presentation at the China-US Collaborative Research Symposium on Life in Terrestrial Geothermal Springs, June 26-28 in Kunming, China.

• Fairbanks, Dawson, Ashley Craig, Catherine Gehring. Alterations in soil microbial communities in Tamarisk impacted soil: effects on growth and establishment between exotic Russian olive and native Fremont Cottonwoods. (2013 ). Poster presentation at Northern Arizona University Undergraduate Research Symposium, Flagstaff, Arizona.

• Dijkstra, Paul, Kees-Jan van Groenigen, Shannon Hagerty, Elena Salpas, Dawson Fairbanks , Bruce Hungate, George Koch, Egbert Schwartz. Metabolic Flux Analysis of Microbial Communities in Soils, Litter, and Hot Spring Sediments. (2013 ). Oral Presentation at the 4^th Annual Argonne Soil Metagenomics Meeting, Chicago, Illinois.

• Dijkstra, Paul, Kees-Jan van Groenigen, Shannon Hagerty, Elena Salpas, Dawson Fairbanks, Bruce Hungate, George Koch, and Egbert Schwartz. Measuring and modeling C flux rates through the central carbon metabolic pathways in microbial communities using position-specific ¹³C-labeled tracers. (2012 ). Oral presentation at the American Geophysical Union December Meeting, San Francisco, California.

• Fairbanks, Dawson, Bruce Hungate, George Koch, Egbert Schwartz, Scott Thomas, Brian Hedlund and Paul Dijkstra. Evaluating metabolic models of intact soil microbial communities using position-specific ¹³C-labeled glucose. (2012). Poster presentation at the American Geophysical Union December Meeting, San Francisco, California.

Publications

• Dijkstra, Paul, Elena Salpas, Dawson Fairbanks, Erin Miller, Shannon Hagerty, Bruce Hungate, Jane Marks, George Koch and Egbert Schwartz. (Submitted to Ecology Letters). Evaluating and Comparing Metabolic Models for Soil Microbial Communities.

Computer & Software Skills

• Programming: R
• QIIME

Awards and Honors

• 2014 Graduate Professional Student Council Research Travel Grant; $650
• 2014 SWES Graduate Student Research Travel Grant; $300
• 2014 Completion of Colorado State University's Summer Soil Institute
• 2014 Sloan Indigenous Graduate Partnership Fellowship, University of Arizona; $38,500
• 2014 UA Graduate Access Fellowship, University of Arizona; $10,000
• 2012 Hooper Undergraduate Research Awards, Northern Arizona University; $3,500

Hobbies

• I enjoy hiking, climbing, yoga, downhill skiing, and sometimes running :)
• I also love painting, pottery, and gardening. I am the current proud owner of 4 laying hens.
• I grew up on a sailboat in southeast Alaska and I love being on the water kayaking and paddle boarding.
• I've worked a variety of different jobs and even spent one summer working with bears in Alaska at a wildlife observatory.
• I've also done conservation work in Arizona working on a saw crew and enjoy tinkering with chainsaws in my spare time ;)