People

Current Members/Affiliates


Scott Saleska

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.


Sky Dominguez


Richard “Rick” Wehr

I am a Research Scientist in the Saleska Lab, studying biosphere-atmosphere gas exchange and how it derives from biological processes and physical transport mechanisms in ecosystems. Currently I am focused on methane emissions from arctic peatlands (using isotopic gas measurements to study the subsurface chemistry and transport that underlies those emissions), and on carbon uptake by temperate and tropical forests (using the forest-atmosphere exchange of CO2 isotopologues to study whole-forest photosynthesis and respiration). I have also worked on temperate forest stomatal conductance and transpiration (probed using carbonyl sulfide uptake), tropical forest photosynthetic seasonality, and eddy covariance methodology. I began working in ecology and biogeochemistry after a doctorate in atmospheric physics at the University of Toronto, which informs the approaches I use.


PostDoc

Andreas Braendholt


 Mauro Brum

downloadI’m currently a post-doc researcher in Saleska lab. I am broadly interested in understanding the ecological process underlying plant co-existence and niche partitioning in high diverse tropical ecosystem. My research focuses describing plant water use strategies and how do plants cope with extreme drought in Amazon forest in Brazil. Actually, my research goal is to understanding how plant hydraulic traits plasticity affect species survive in water limited ecosystem. I seek to understanding how plants change they physiology along they ontogeny as the individuals change the hydrological niche defining by changes in vapor pressure deficit in vertical forest structure; and seasonal changes soil water moisture in vertical soil profile.


Graduate Students

Neill Prohaska

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.


Moira Hough

I am currently a PhD candidate in the Saleska lab. 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.


Shuli Chen


Undergraduate Students

Matthew Gold


Agustina Rosati


Research Consultant

Natalia Restrepo-Coupe

I had the honor of being the first post-doc in the Saleska Lab from 2006-2011.  In 2015, I again started working with the Saleska Lab as a research consultant managing the eddy covariance, SIF, thermal and hyperspectral camera measurements at Santarem K67 -our Amazon research site.


 Former Member/Affiliates


Loren Albert

Loren is a plant ecophysiologist with a focus on scaling between leaf-level function and ecosystem-level processes in forests. Her past research includes studies examining how the timing of leaf production impacts the seasonality of carbon uptake in Amazonian evergreen forests, and how such phenological processes can be incorporated into land surface models.  At Brown Loren is investigating how optical signals from leaves can be used to probe photosynthesis at scales from leaves to canopies under a range of conditions. Loren draws upon tools from the fields of ecology, evolution, micrometeorology, plant physiology and remote sensing in her research.

Loren earned her bachelor’s degree in Biology at Reed College, and then spent several years as a research associate at Rice University studying plant ecology and evolution before beginning her graduate studies in plant ecophysiology and ecosystem science at the University of Arizona in the Ecology and Evolutionary Biology Department.


Bradley Christoffersen

I am a broadly trained ecologist, with extensive experience in tropical forests and soon the thornscrub ecosystems of the Rio Grande Valley. My research focuses on plant physiological ecology, ecosystem ecology, and models which scale up processes from plant tissues to whole ecosystems.

I am interested in how plants use diverse ecological strategies to maximize growth, survival, and reproduction under conditions of water scarcity, and the impacts of such ‘functional diversity’ on the resilience and vulnerability of ecosystems to environmental change. Historically I have pursued these questions in tropical forests, but will be expanding my focus into native and disturbed ecosystems of the Rio Grande Valley. I will use diverse approaches including minirhizotrons to study fine root growth and turnover in response to varying hydrological regimes; micrometeorological techniques (eddy covariance) to study the net exchange of carbon, water, and energy between the land and atmosphere, lab-based investigations into the impact of tree allometry, architecture, and phenology on the diversity in stem and leaf hydraulic traits of native thornscrub species, and model-data fusion techniques for high-frequency environmental data on plant-water relations, such as continuous sap flow (stem water use) and water potential measurements from in situ plant sensors.


Anthony “AJ” Garnello

Explorations into the boundary of ecosystem-climate interactions through the lenses of biogeochemistry and ecology in the face of climate change, with a predominant focus on Arctic peatland and tundra.


Joost van Haren

My research focuses on understanding biogeochemical cycles of carbon, nitrogen and water in particular in tropical ecosystems.  Tropical ecosystems are among the most dynamic ecosystems that have strong feedbacks to human disturbance. Deforestation and climate change both affect the biogeochemical cycles in tropical forests and we mainly measure greenhouse gas fluxes and couple these to biological activity.  Currently, we work on understanding carbon and water cycling in tropical peatlands, more specifically, methane emissions from these ecosystems and also how land-use change affects methane fluxes and the microbial community responsible for the methane fluxes.

In Biosphere 2 we use both the tropical rainforest and the LEO hillslopes to better understand the carbon and water cycling in these disparate ecosystems.  In LEO, we look at the carbon cycling and how weathering is affected by precipitation events. In the rainforest, we particularly look at how individual species and the whole ecosystem respond to changes in temperature and precipitation.  During drought experiments we work together with Dr. Jeffrey McDonnell to determine where tropical trees get their water from and how this changes with rainfall events.


Carrie McCalley


Laura Meredith



Virginia Rich

My lab studies how microbes respond to, and in turn help shape, environmental change. We are particularly interested in global change interactions with biogeochemical cycling. Our lens into microbial community composition and function is through molecular “meta-omics” tools, which we bring to robust interdisciplinary collaborations with biogoechemists and modelers to generate a systems-level understanding of ecosystems undergoing change.


Marielle Smith

I explore how environmental variations in temperature and precipitation affect tropical forest canopy structure, and how this, in turn, affects forest function. Characterising how climatic variations affect forest structure and function is particularly important in tropical forests, which are globally important carbon stores that have already shown vulnerability to climate change. The future of tropical forest carbon stocks is highly uncertain, with plant physiological responses representing the largest source of model uncertainties. As such, my research comprises empirical investigations into how tropical forests will respond to high temperatures and drought. My study sites include the tropical forest biome at Biosphere 2 (B2) and natural sites in the eastern Brazilian Amazon.

I am investigating how tropical forest canopy structure responds to seasonal dry periods and anomalous droughts on seasonal and interannual timescales, using data from ground-based LiDAR (Light Detection and Ranging). Combining long-term LiDAR measurements with tree inventory data provides a way to identify the mechanisms (i.e., changes in leaf area and/or woody biomass) responsible for structural changes associated with drought-induced disturbances and subsequent periods of forest recovery.

To understand the response of tropical forests to high temperatures, I am comparing the temperature response of gross ecosystem productivity in an experimentally warmed forest—the B2 tropical forest biome—with natural tropical forests using eddy-covariance data.


Scott Stark

Forest–Atmosphere Interactions | Earth Systems | Plant Community, Ecosystem, and Physiological Ecology. My research combines data from traditional forest plots, ecophysiological information, and LiDAR remote sensing to study the combined effects of size structure, light limitation, and phenotypic diversity on tropical forest dynamics and functions, including biosphere–atmosphere interactions and ecoclimate teleconnections.


Tyeen Taylor


Pilar Vergeli


Richard Wehr

I am a Research Associate in the Saleska Lab, studying biosphere-atmosphere gas exchange and how it derives from biological processes and physical transport mechanisms in ecosystems. Currently I am focused on methane emissions from arctic peatlands (using isotopic gas measurements to study the subsurface chemistry and transport that underlies those emissions), and on carbon uptake by temperate and tropical forests (using the forest-atmosphere exchange of CO2 isotopologues to study whole-forest photosynthesis and respiration). I have also worked on temperate forest stomatal conductance and transpiration (probed using carbonyl sulfide uptake), tropical forest photosynthetic seasonality, and eddy covariance methodology. I began working in ecology and biogeochemistry after a doctorate in atmospheric physics at the University of Toronto, which informs the approaches I use.


Kenia Wiedemann


Jin Wu

Jin Wu is a broadly trained environmental scientist studying the interaction of forest ecosystems with climate. He shares a very broad research interest in plant physiology, ecosystem science, ecological strategies, biodiversity, and community assembly. Jin is especially keen to advance our understanding of these topics by using multi-discipline approaches (remote sensing, gas exchange measurements, biometry surveys, earth system modeling) undertaken across a wide range of scales (leaf, canopy, landscape, globe). His current research is focused on understanding and model representation of the processes that underlie the response of tropical forest ecosystems to global change. Jin is also involved in promoting science by mentoring undergraduate/graduate students interested in environmental sciences.


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