University Programs

REU Projects

At the University of Arizona, we are building a program to bridge the gap between laboratory- and field-scale studies by utilizing the unique infrastructure of Biosphere 2. Biosphere 2 offers unique opportunities for the exploration of complex questions in Earth sciences because of its ability to combine varying scales, precise manipulation and fine monitoring in controlled experiments. By building upon the large external scientific network at the University of Arizona in hydrology, geology, geochemistry, ecology, biology, physics, engineering and atmospheric sciences, we are developing a strong multidisciplinary team of researchers who are undertaking the design and deployment of top-notch science to address complex questions in environmental sciences. Projects for 2019 REU students include:


Ecosystem Science, Renewable Energy Production, Food, and Water Sustainability

Greg Barron-Gafford, Department of Geography and Development, and Biosphere 2. External forces (like environmental and human factors) and internal characteristics (like plant ecophysiology) determine where species can live and thrive. This nexus is critical for tackling one of the greatest challenges facing our future - how to simultaneously maximize renewable energy production and food production without degrading the environment. The "Agrivoltaics" installation at B2 blends renewable energy production from solar photovoltaics with agriculture to study the impacts of this novel approach on plant function, water use, and biomass production.


Abiotic Effects and Dynamics of Woody Plant Cover

David Breshears, School of Natural Resources and Environment. Gradients of woody plant cover, which can span from grassland to forest, inspire questions about abiotic effects of woody plants and responses to changes in climate or land use. Projects could include assessments of changes in near-ground microclimate conditions associated with different densities of woody plant cover, spatial variation in dust production as a function of woody plant cover, and/or plant water stress preceding tree mortality along vegetation gradients. Approaches include hemispherical photography and computational assessments of solar radiation regimes, measurements of dust production using a variety of instruments, and/or measurements of plant water stress and related physiological metrics.


Coupling Subsurface Biogeochemistry to Critical Zone Evolution

Jon Chorover, Soil, Water and Environmental Science Dept. Chorover’s lab provides opportunities to investigate biogeochemical aspects of the CZO, including work at one of two sites within the UA CZO: Santa Catalina Mountains (AZ) and Jemez River Basin (NM). Students would couple field work and laboratory studies to understand subsurface biogeochemical processes and their interaction with Critical Zone ecohydrology, stream water dynamics, and landform evolution.


Mineral Weathering, Soil Formation and Carbon Sequestration as Influenced by Water Flow and Biota

Katerina Dontsova, Biosphere 2. Projects at B2 would focus on soil formation processes and development of subsurface heterogeneity through hydrologic-geochemical coupling using direct measurement and geochemical modelling: what happens in the basalt covering LEO slopes as a result of water flow and biological activity; what is the role of slope position, water residence time, and microbial activity on total weathering, chemical denudation, formation of high surface-area secondary solids, and accumulation of organic and inorganic carbon.


Hydrogeology as a Model for Everything

Ty Ferre, Department of Hydrology and Atmospheric Sciences. What does underground water flow have to do with traffic jams, internet memes, and getting a good table at a popular restaurant?  It's all about connections.  This project will involve thinking creatively about what the term 'connectivity' means.  Students will learn how to use and write simple computer codes to explore how water flows through a nonuniform soil.  The goal will be to better understand this critical element of the LEO hillslopes and to relate the findings to as broad a range of topics as possible. 


Microbes as the engineers of the soil, plants, and atmosphere of Biosphere 2

Laura Meredith, School of Natural Resources and Environment. How do microbes survive and thrive in diverse biomes and different ecosystem compartments including water, soils, the surface and interior of leaves, and air? How do differences in the microbiomes of different ecosystem compartments highlight their ability to affect the biosphere, and specifically, its atmosphere? Our research explores how microbial communities in the Tropical Rainforest and the Landscape Evolution Observatory affect atmospheric composition by their production and consumption of trace gases that affect climate and air quality. The student(s) involved in this project will have the opportunity to learn methods in microbial genomics, bioinformatics, and analytical atmospheric chemistry and contribute to key preparations for an international research campaign in the Tropical Rainforest.


Developing, Improving, and Testing a Computer-based, Terrestrial Integrated Modeling System (TIMS)

Guo-Yue Niu, Department of Hydrology & Atmospheric Sciences, and Biosphere 2. TIMS focuses specifically on the interaction between hydrological, microbial, geochemical, geomorphological and ecological processes at the Earth’s land surface. TIMS takes advantage of existing state-of-the-art community models (e.g., CATHY and Noah-MP) and couples states and fluxes between the models to study interaction and feedback. TIMS is being developed using an experimentation-model learning cycle, so that new data derived from B2 physical models, e.g., LEO and the rainforest, can help us improve our understanding and parameterizing of fundamental processes.


Interaction of Landscapes, Pedogenesis and Mass Fluxes

Craig Rasmussen, Soil Water and Environmental Sciences Department. Landscape scale variation in chemical and physical weathering has emerged as a key modulator of terrestrial biogeochemistry. In particular, CO2 consumption associated with mineral weathering and the interaction of this process with pedogenesis and erosion appear to be significant factors controlling long-term patterns in atmospheric CO2 concentration. Weathering and mass flux are hypothesized to vary predictably with landscape position and climate forcing. Testing of this hypothesis involves quantifying the mass flux of elements such as Na and Si from soil profiles located at various landscape positions in the Santa Catalina Mountains using field sampling, laboratory analyses, and data synthesis.


What's in a Handful of Soil?

Malak Tfaily, Soil, Water, and Environmental Science. If you walk outside or through a forest, you’ll probably see life everywhere: trees, animals and fungi, all live in one ecosystem! And what allows for such great diversity? Something you are very familiar with: soil! Soils are the largest reservoir of carbon on Earth’s terrestrial surface, storing at least three times as much carbon as found in the atmosphere in the form of soil organic matter. In spite of its significant role in the global carbon cycle and thus climate change, the dynamics and composition of soil organic matter are poorly understood. Our research explores soil organic matter composition in the Tropical Rainforest and the Landscape Evolution Observatory and how this composition changes with changing plants and microbial communities. The student(s) involved in this project will have the opportunity to learn methods in molecular characterization of soil organic matter (i.e, identify the molecules that are in soil) bioinformatics, and soil chemistry and contribute to key preparations for an international research campaign in the Tropical Rainforest.


Marine biogeochemical cycling in the Biosphere 2 Ocean (B2O)

Diane Thompson, Department of Geosciences and Biosphere 2. As the Director of Marine Research at the Biosphere 2, Thompson and the B2O team are leading an exciting new three-phase project that will investigate key processes and novel solutions for restoring resilient coral reefs from a degraded state. The algae-dominated reef state of the current B2O — similar to that of a degraded reef after disturbance(s) — presents a unique opportunity to investigate recovery processes and explore restoration solutions. During this critical first phase, we are closely monitoring the physical, chemical, and biological conditions of the B2O to document the transition from algae to coral reef as we re-engineer the system to support a “super reef” of the future. Students will work with the B2O team to unravel the complex biogeochemical cycling on degraded coral reefs, as well as their evolution and role in the reef restoration process.


Water Transit Time at Catchment Scales

Peter Troch, Department of Hydrology & Atmospheric Sciences, and Biosphere 2 (Science Director). Troch studies catchment scale hydrological processes via advanced measurement, modeling and synthesis to 1) Develop, test, and apply advanced observation methods for hydrological fluxes and states at a range of spatial and temporal scales; 2) Develop hillslope-to-catchment scale hydrological models for water and solute transport; 3) Understand hydrological synthesis at the catchment scale with special attention to extremes; 4) Determine effect of scale on co-evolution of hydrological and geochemical processes. Findings contribute to improved water resources management in light of climate change and other human influences. Students can work on water transit time estimation using stable isotope data from rain and streamflow samples combined with field and lab work including running the laser spec, and mathematical modeling of flow and transport processes at catchment scales using both LEO and CZO watersheds.


Tropical Forest Dynamics and Trace Gas Fluxes

Joost van Haren, Biosphere 2. Tropical forests are among the most dynamic ecosystems in the world, but their responses to climate change are uncertain. B2 provides an opportunity to study tropical ecosystems under future conditions (increased temperature, decreased precipitation); the large enclosure and artificial rainfall allows precise determination of water and carbon movement through the biome. Students use the B2 tropical forest to assess plant, hydrological, and carbon cycling responses to altered temperature and precipitation.


Hydrologic Flow and Transport at Hillslope Scales

Minseok Kim and Peter Troch, Biosphere 2. Tracing (isotopically or chemically) ‘tagged’ water particles help us understand flow pathways inside a hydrologic system. The Landscape Evolution Observatory (LEO) hillslopes at Biosphere 2 provide us unique opportunities to conduct experiments with tagged water particles and to monitor those movements inside the hillslope at the unprecedented spatio-temporal resolution. We use the experimental data to develop and to test hypotheses, theories, and models. Students involved in this project will have opportunities to learn how we conduct experiments and monitor the hillslopes; to analyze isotopic composition and chemistry of water samples that collected at the LEO hillslopes; to learn hydrologic flow and transport theories and models.