Saleska lab members and associates
Current lab members
My research focuses on what might be called “biogeochemical ecology,” asking questions about how climate interacts with plant physiology, demography, and ecological processes to influence or control biogeochemical cycling from local to global scales. Just one example of the need for more complete understanding in this area is the lack of species interactions in modern global climate models, even though such interactions can be critically important in controlling ecosystem carbon cycling and hence, feedbacks to climate. Progress has been limited by the difficulty of bridging the gap between local-scale ecological interactions and broader biogeochemical processes. I use multidisciplinary approaches that combine classical techniques of field ecology and forestry with advanced technological methods (e.g., the micrometeorological eddy covariance method, isotopic techniques) and modeling to integrate biogeochemical processes to ecosystem scales.
Rick Wehr (Post doc)
My research concerns biosphere-atmosphere interactions and focuses on improving our quantitative understanding of how the microscopic biological processes governing the exchange of carbon and water in leaves and soils (e.g. photosynthesis, respiration, methanogenesis) manifest at the ecosystem scale over hours, days, seasons, and years. These processes have a strong influence on the trajectory of climate change through feedbacks between atmospheric composition and the behaviors of forests, wetlands, and other ecosystems. My work includes the development and implementation of methods for measuring these processes (e.g. stable isotope flux measurements), fieldwork, the analysis of long-term datasets, and the construction of numerical models. For example, at a temperate forest in New England, I have been making laser-spectroscopic measurements of CO2 isotope fluxes since 2011 and using those measurements to independently estimate ecosystem-scale photosynthesis and respiration. At an arctic wetland in Sweden, I helped establish similar measurements of methane isotope fluxes in order to link methane production pathways to microbial ecology as permafrost thaws. At each site, I have been building numerical models of gas and energy transport to mechanistically link the leaf, root, and microbial processes to the three-dimensional ecosystem.
Moira Hough (PhD candidate)
I am broadly interested in understanding the role of organisms and biodiversity in driving biogeochemical cycles, particularly with respect to global change. My doctoral research focuses on tracing carbon transformations and fluxes through Arctic systems across a permafrost thaw gradient. As permafrost thaws, previously frozen carbon and nutrient pools are released. Simultaneously, associated hydrologic changes drive shifts in plant community composition with concurrent changes in microbial communities. I seek to understand how plant and microbial communities interact during these transitions and how they drive pathways of carbon flow within the system and export to other systems. I also teach inquiry-based outdoor science programs to K-12 students at the UA Sky School (https://skyschool.arizona.edu/).
I study how leaf-level light environment affects leaf demography and phenology in the Amazon forest. My research is particularly focused on the relationship between leaf traits, leaf demography, and light environment across spatial and temporal scales. I am broadly interested in the question of how functional traits can be used to improve our understanding of the scaling relationships between leaf, tree, and landscape level ecological processes, and the use of near-remote sensing (e.g. tower mounted cameras) to understand tropical forest phenology patterns. I also specialize in adapting climbing techniques from my rock and industrial climbing experience to enable new canopy research methods.
My name is Anthony Garnello, and I’m a Master’s student in Ecology and Evolutionary Biology here at the University of Arizona. I’m currently operating a multi-band (red, green, blue, and near-infrared) camera on top of a 5-meter tower that is automatically capturing images throughout the growing season of a subarctic peat bog in northern Sweden. This project aims to measure the plant phenology in a climate-vulnerable ecosystem that is experiencing warming-induced increases in greenhouse gas ebullitions. By combining camera-derived plant growth indices with other measurements including seasonal peat fluxes of methane and carbon dioxide, microbial genetics and protein expression, and geochemical and isotopic content, I aim to establish a link between powerful remote sensing tools and ecologically significant indicators of permafrost thaw and carbon cycling.
I joined Dr. Saleska’s research team in 2012 as an undergraduate at the University of Arizona, and as an undergraduate I led two independent research projects exploring leaf biophysical changes due to senescence. These experiences introduced me to larger-scale ecosystem carbon and energy-cycling experiments in the Amazon rainforests of Brazil and the subarctic peatland of northern Sweden. My undergraduate thesis examined the different sub-biomes at our arctic peatland field site that contribute strongly to the spatial variation in methane and carbon dioxide emissions. I used a hyperspectral sensor combined with plant community composition measurements to create a numerical model that classifies land cover type with 92% accuracy (unpublished). Moving forward, I aim to continue to explore the boundary between climate and ecosystem (known as ecoclimate) using remote sensing equipment.
My name is Rose Vining and I am currently a junior at the University of Arizona, majoring in environmental science with a focus in ecology. I started in a microbial ecology lab under the guidance of Dr. Virginia Rich (http://openwetware.org/wiki/SWES-MEL) and was funded through the Undergraduate Biology Research Program (UBRP, http://ubrp.arizona.edu/). I started my research by looking at the composition of microbial communities from a polluted and relatively pristine site at the Great Barrier Reef, in order to see whether microbes had the potential to uptake the pollutants and buffer the fragile ecosystem. More recently I have been involved in a project that is dealing with the effects of climate change on thawing permafrost ecosystems, through the co-mentorship of Dr. Rich, Dr. Scott Saleska and Moira Hough.
This summer, I was funded through my research program to apply my skills in Abisko, Sweden. My focus was on how plant community composition changes across a permafrost thaw gradient. This is important to the rest of my lab’s work because plant litter provides a key source of carbon to microbes, which produce greenhouse gases through respiration and extenuate the process of climate change. I am passionate about my work, since climate change will have major implications for humans in the near future. I plan to continue my studies past college and am hungry to keep learning. I would like to work for the park service one day, and hopefully be on the front lines of habitat restoration!
I study tropical forest responses and feedbacks to climate change. My primary study sites are The University of Arizona’s Biosphere 2 and the Amazon forest. The Amazon forest contains a quarter of the world’s land species, and, through photosynthesis and respiration, processes twice the amount of carbon dioxide that is emitted by humans each year. Any responses of the Amazon forest to climate change will have large feedbacks to global climate and biodiversity.
My research examines how heat and drought alter species assemblages in tropical forests, and how the changing ‘plant community’ alters ecosystem function. A unique contribution of my research is the incorporation of an interesting plant trait—the emission of isoprene gas—into this community ecology context. My focus on species distributions and field-measured characteristics is uniquely suited to my background in tropical plant identification and backcountry exploration.
I contribute to public education about science and the natural world through numerous public and classroom talks, photography, short films, and writing.
Want to learn or teach programming in R? Check out my comprehensive tutorials, available here.
Marielle Smith (PhD graduate)
I am studying how tropical forest canopy structure changes in response to seasonal and interannual variations in climate in evergreen forests in the Brazilian Amazon. I am also interested in understanding how changes in canopy structure are related to ecosystem carbon dynamics. Canopy structure is the three-dimensional configuration of all the leaves, twigs, and branches in a forest. The forest canopy is an important mediator of forest-atmosphere interactions, being the site of forest photosynthesis, where carbon dioxide, water, and energy are exchanged between vegetation and the atmosphere. Given the fundamental interaction of the canopy with the atmosphere, understanding patterns of forest canopy structural change can help identify mechanisms by which forests respond to and influence climate. I am using ground- and airborne-LiDAR (light detection and ranging) to measure canopy structure. The LiDAR instrument fires high frequency laser pulses at the forest canopy and a sensor measures the amount of time it takes for a pulse to leave the instrument, intercept vegetation, and return to the sensor. That time is then converted into a distance to the target.
My research also involves investigating the potential for tropical forests to acclimate to high temperatures by analysing whether an artificial tropical forest (the Biosphere 2 tropical forest biome) exposed to high heat is more temperature tolerant than real-world tropical forests. To do this, I am comparing the temperature response of gross ecosystem productivity in the B2 forest with natural tropical forests.
My research revolves around plant ecological physiology and ecosystem science. My research program is diverse—I study systems from lowland Amazonia to sub-alpine forests, at the scales of leaves to ecosystems. Across these systems and scales, I seek to understand how climate interacts with plant biology, and how, in turn, plants function to shape the flows of carbon, water, and energy in ecosystems. I am particularly interested in how climate change will affect these dynamics.
I earned my bachelor’s degree in Biology at Reed College, and then spent several years as a research associate in the Rudgers and Whitney labs at Rice University studying plant ecology and evolution before commencing my graduate studies at the University of Arizona in the Ecology and Evolutionary Biology Department. At the University of Arizona, I have had the opportunity to collaborate with some truly incredible scientists with multidisciplinary backgrounds. The breadth of my training enables me to draw upon tools from the fields of ecology, evolution, micrometeorology and physiology in my research.
In my research I seek to quantify the microbial imprint on atmospheric composition and climate using an interdisciplinary set of laboratory and observational methods ranging from molecular biology to micrometeorology. I am particularly interested in characterizing the role of soil microorganisms in driving biogeochemical cycles and in developing tools to overcome the challenges of soil complexity and the wide-ranging scales involved in studying gene to environment linkages. Microbe-mediated biogeochemical cycles represent an important link between societal choices regarding land use, ecosystem services, and global climate change.
In the Saleska group at the University of Arizona I will be working with Scott Saleska, Joost van Haren, and our many collaborators on a project linking taxonomy, genes, and function to methane fluxes in the Brazilian Amazon. I recently completed my postdoctoral work at Stanford University as an Atmospheric and Geospace Sciences NSF Postdoctoral Fellow in Paula Welander’s geobiology lab and Joe Berry’s trace gas lab. There, I investigated microbial controls on soil cycling of COS and oxygen isotopes of CO2, two potential carbon cycle tracers. I earned my PhD in the Program in Oceans, Atmospheres and Climate, Department of Earth, Atmospheric and Planetary Sciences, at MIT in 2013 in Climate Physics and Chemistry with Professor Ron Prinn. My dissertation focused on the significant, but poorly understood microbe-mediated soil sink for atmospheric H2. I earned a Bachelor of Science in Chemistry in 2005 from the California Polytechnic State University (Cal Poly), San Luis Obispo. I am originally from Southern Oregon and enjoy hiking, camping, biking, yoga, rock climbing, and learning languages.
(Now at Brookhaven National Laboratory) I am an ecosystem ecologist and remote sensing scientist and doctoral candidate in the Ecology and Evolutionary Biology department of theUniversity of Arizona. Generally, my research interests focus on plant physiology, phenology, functional traits, ecological strategies and community assembly. I am especially enthusiastic in advancing these topics by using multiple advanced remote sensing tools undertaken across a wide range of scales (leaf, canopy, landscape, and continent). I am also involved in promoting science by mentoring undergraduate students interested in ecology.
For my dissertation research, I aim to reveal the mechanistic controls on tropical forest photosynthesis seasonality by quantifying the relative importance of environmental variation, canopy phenology and canopy physiology. To address this, my projects focus on 1-extracting canopy phenology and demographic seasonality (as measured by age dependent LAI) from image series of multiple sources; 2-developing a simple model (cored by a dynamic canopy demographic model) to explain photosynthetic flux seasonality in tropical forest system; 3-involved with several field campaigns (and intensive ecophysiological measurements) in Amazon rainforests; 4-attempting to use a very sophisticated process based model (FLiES) and sensitivity analysis to reveal key mechanisms regulating tropical forest photosynthesis seasonality. My core field site is in Tapajos National Forest, K67 site, near Santarem, Brazil.
Besides my dissertation topic, I am also dedicated to working on two side projects: (1) develop a hyperspectral version of leaf economic spectrum by linking leaf level hyperspectral reflectance to leaf physical, chemical, functional and phonological properties; (2) develop a conceptual framework of phenology diversity and temporal niche partitioning.