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MEET A LEAF: Teamrat A. Ghezzehei

12/30/2019

Dr. Teamrat A. Ghezzehei is a Professor of Soil Science at the University of California, Merced.
Twitter: @teamrat

Teamrat measuring soil infiltration at an experimental field near Thies, Senegal, while former Ph.D. student Nate Bogie (now an Assistant Professor at San Jose State University) was testing buried soil sensors. The study (NSF-PIRE funded) was investigating the agroecological benefits of intercropping food crops with deep-rooted native shrubs.

What does ecohydrology mean to you?
I am interested in the hydrologic drivers that explain the diversity and resilience of plants and soil microbial communities. Specifically, I seek to understand hydrologic thresholds for plants and microbes and the mechanisms that they employ to adapt to hydrologic fluctuations.

What are your undergraduate and graduate degrees in?
BS in Soil & Water Conservation from the University of Asmara (Eritrea). I wrote my senior thesis on composting Prickly pear peels to reclaim degraded soils. I received by Ph.D. in Soil Science (emphasis in Soil Physics) from Utah State University, where my dissertation research was concerned with micromechanics of soil aggregates.

How did you arrive at working in/thinking about ecohydrology?
My training and early research primarily focused on the physics of fluid flow in porous media and was devoid of biology. My approach changed when I started addressing problems of water dynamics in the rhizosphere. The rhizosphere (the small volume of soil that surrounds plant roots) is the window through which all the transactions between plants and soils are conducted. It is also home to the most diverse microbial communities and biogeochemical cycles that occur in soils. I was particularly fascinated by the exquisite hydraulic engineering performed by plants to make the rhizosphere adaptable to unpredictable moisture dynamics. Over the years, my interest broadened to include hydraulic redistribution by plant roots, plant-plant resource sharing, hydrologic controls on soil organic matter cycling, and agroecological applications of these processes.

What do you see as an important emerging area of ecohydrology?
I think interfaces, both physical and intellectual, are often fertile areas for new directions. Interfaces among living organisms (plants and microbes) and between organisms and their abiotic environments as distinct regions of complex interactions are ripe for renewed exploration. The topic can benefit from the current scientific climate that encourages inter-disciplinary collaborations and team science.

Do you have a favorite ecohydrology paper? Describe/explain.
Hinsinger, P., Bengough, A. G., Vetterlein, D., & Young, I. M. (2009). Rhizosphere: biophysics, biogeochemistry, and ecological relevance. Plant and Soil, 321(1-2), 117-152.
This review paper was instrumental in opening my eyes to the fascinating topic of the rhizosphere. Perhaps because some of the co-authors are soil physicists, it's presentation was accessible to someone with my kind of academic background, and it introduced me to the open research gaps that I could help fill.

What do you do for fun (apart from ecohydrology)?
I enjoy photography a lot. When I was in graduate school, my good friend Markus Tuller (now a Professor at the University of Arizona) introduced me to hiking and nature photography. We visited most of the National Parks in Utah and Wyoming. It helps me to slow down and take in the beauty of the places that I get to visit. I am lucky that I live very close to Yosemite that gives me plenty of opportunities to practice. A selection of shots from my travels is available on my lab website.
http://soilphysics.ucmerced.edu/gallery/gallery-travel.htm

I also occasionally share random photos on Instagram:
https://www.instagram.com/teamrat.ghezzehei/

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MEET A LEAF: Fabrice Vinatier

12/23/2019

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Fabrice Vinatier is a researcher in the LISAH laboratory at Montpellier, France. @FabriceVinatier

What does ecohydrology mean to you?
Ecohydrology focuses on the close interrelationships between plants and the hydrosystem, and I am particularly interested by the way man could modulate these interrelationships.

What are your undergraduate and graduate degrees in?
MS in Agronomic Engineering and PhD in Spatial Ecology, both from AgroParisTech (France).

How did you arrive at working in/thinking about ecohydrology?
When I arrived at the LISAH laboratory seven years ago, I realized the importance of studying ecological processes in agricultural watersheds, thanks to the impetus of my colleague Jean-Stéphane Bailly. The impact of vegetation on water movement is so important to explain the redistribution of water in watersheds, but generally underestimated because of the complexity of the links between these two objects, studied by different disciplines: ecology and hydraulics. Ecohydrology, and in particular ecohydraulics, has been the most integrative discipline in which I have learned to understand these links. I also benefit from the Montpellier SupAgro hydraulic laboratory, thanks to Gilles Belaud, to carry out controlled experiments on plant materials and water flows. In addition, as an engineer by training, it was important for me to find ways to preserve water resources by acting on agricultural practices that have an impact on the water-plant system. I agree with another leaf, Mitch Pavao-Zuckerman, when he says that people have an important role to play in ecohydrology!

What do you see as an important emerging area of ecohydrology?
In my opinion, there is a lot of work to be done on the characterization of functional traits of plants that influence, or are influenced by water movements. A lot of processes occurred in natural or semi-natural lands with a mix of plants that are sometimes submerged during raining events. The functional trait approach developed in community ecology has mainly been devoted to life traits related to competition between plants for light or nutrients, or even water transfers by evapotranspiration, but rarely related to lateral flows.

Do you have a favorite ecohydrology paper? Describe/explain.
The paper Nepf, H. (2012). Hydrodynamics of vegetated channels. Journal of Hydraulic Research, 50(3), 262–279. https://doi.org/10.1007/978-3-319-17719-9_21 was an excellent overview of the complex links between vegetation and hydraulics. This paper paves the way for an analytical resolution of water-plant interactions, and was really inspiring for my research.

What do you do for fun (apart from ecohydrology)?
I like biking in the countryside and walking with my family in the city of Montpellier.

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MEET A LEAF: Jeannie Wilkening

12/16/2019

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Jeannie Wilkening is a PhD Student in Environmental Engineering at UC Berkeley. @jvwilkening

What does ecohydrology mean to you?
I see ecohydrology as the intersection of water and life, whether that interaction is taking place at the scale of a single plant, a catchment, or the entire globe. The feedbacks at this interface create dynamic systems that not only makes ecohydrology a really fun area of science to be working in, but also means we are looking at a lot of important questions to help understand how the environment is functioning now, how that might change in the future, and how we might best manage our environment for a more sustainable future.

What are your undergraduate and graduate degrees in?
I have an undergraduate degree in Chemical Engineering from University of Arizona, an MPhil in Earth Sciences from University of Cambridge, an MS in Environmental Engineering from UC Berkeley, and am currently a working on my PhD in Environmental Engineering at UC Berkeley.

How did you arrive at working in/thinking about ecohydrology?
My undergraduate degree was in chemical engineering, but during my undergrad I spent a summer doing research on photosynthetic traits at the University of Michigan Biological Station. Over the course of doing field research that summer, I came to realize that actual plants were a lot more interesting than chemical plants. After a brief stint in biogeochemistry during my masters, I was drawn to ecohydrology when I found Sally Thompson’s group at UC Berkeley, largely because I just thought she was looking at some interesting questions in really fascinating ways. In retrospect, ecohydrology was a perfect area for me to end up since it allows me to take a lot of the fundamentals and problem solving that I liked in chemical engineering and just apply them in a different context. It’s still a matter of using fundamental concepts of physics, chemistry, and biology to understand and predict fluxes and transformations, but just applying them to things like trees instead of distillation columns.

What do you see as an important emerging area of ecohydrology?
This is a particularly tough question coming off a fantastic week at AGU Conference which really highlighted how much great and fascinating work that is being done in all sorts of areas of ecohydrology. Leaning into my engineering bias towards applied problems, I think it’s really interesting to see the ways in which advances in ecohydrology can help to address the very real and growing challenges we are facing as a society ranging from managing increasingly scarce water resources to feeding a growing population to supporting ecosystem function and services under increasing stresses. As many of the issues we face with a changing climate involve that interface between life and water, I think we have a lot of power as ecohydrologists to work towards solutions and help guide action and policy.

Do you have a favorite ecohydrology paper? Describe/explain.
At the moment I would probably have to go with Dawson and Ehleringer (1991) “Streamside trees that do not use stream water” since it is one that has really stuck with me on a few different levels. Methodologically, I think it really shows how valuable of a tool stable isotopes can be in ecohydrology. On a broader ecological level, it really opened up a lot of questions that we are still grappling with today about where plants are getting their water from, including how different strategies may have implications for broader ecological processes, particularly in the face of environmental change. Finally, on a more human level, I think the findings of this study really highlight how much there is still left for us to discover about the world around us. It’s these sorts of surprising findings that really make me excited as a young scientist to keep exploring and asking questions.

What do you do for fun (apart from ecohydrology)?
When I’m not debugging code at my computer or getting covered in dirt at the campus greenhouse, I can usually be found running, cheering on my hometown Arizona Wildcats, baking, or longingly staring at any dog I see in public.

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MEET A LEAF: MATT COHEN

12/9/2019

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Dr. Matt Cohen is Professor of Forest Water Resources and Watershed Systems at the University of Florida. @DrAquaMatt

What does ecohydrology mean to you?
The study of the ways in which water, materials and organisms interact.

What are your undergraduate and graduate degrees in?
BS in Environmental Engineering, PhD in Systems Ecology

How did you arrive at working in/thinking about ecohydrology?
As an undergraduate, I did research on treatment wetlands, and expanded that to include wetlands (and then streams, lakes, and aquifers) more broadly as a graduate student. Wetlands are excellent venues for thinking generally about the interactions of organisms and water.

What do you see as an important emerging area of ecohydrology?
It’s not new, but I am most excited about the idea of biogeomorphic feedbacks. The role of biota in regulating the mode and magnitude of geomorphic change, especially in karst systems, is a really compelling example of the deep coupling among processes that is the earth system.

Do you have a favorite ecohydrology paper? Describe/explain.
Among the first papers that got me thinking about biogeomorphic feedbacks was Corenblit et al. (2007) Reciprocal interactions and adjustments between fluvial landforms and vegetation dynamics in river corridors: a review of complementary approaches Earth Science Reviews (84:56-86). That paper explores the complex mosaics of riverine floodplains through a systems lens, wherein sediment transport dynamics, vegetation recruitment and growth, and geomorphic structures are inextricably coupled processes. It weaves in flood disturbances, channel hydraulics, and ecological succession, culminating in the idea that the geomorphic structures that organisms create are a mode of evolutionary inheritance (the extended phenotype concept). We’ve adopted that view for karst and peat wetlandscapes in south Florida.

What do you do for fun (apart from ecohydrology)?
Homesteading, soccer, cooking, woodwork, weightlifting.

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MEET A LEAF: TAMARA HARMS

12/2/2019

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Dr. Tamara Harms is an Associate Professor at the University of Alaska - Fairbanks.

What does ecohydrology mean to you?
Ecohydrology addresses the interface of the hydrologic cycle and ecosystem processes. My particular interest in ecohydrology is in how water contributes to transport and transformation of carbon and nutrients.

What are your undergraduate and graduate degrees in?

B.S. in Microbiology and Ecology, Evolution, & Conservation Biology from the University of Washington
M.S. and Ph.D. in Biology (Ecology) from Arizona State University

How did you arrive at working in/thinking about ecohydrology?
My research interests have always been focused on streams and land-water interfaces. When I learned about the small watershed approach it seemed like a natural way of characterizing the sum total of ecosystem processes, and this approach requires understanding something about how flows of water transport materials. From there it was clear from data I collected in desert riparian zones that water was not just transporting materials but also influencing transformations of carbon and nutrients.

What do you see as an important emerging area of ecohydrology?
I think a lot about how hydrologic flowpaths that connect patches within ecosystems or across regions alter the transport and transformation of materials. The timing, magnitude, and routing of flowpaths are changing rapidly in many places and we know little about the ecohydrological outcomes of changing flowpaths. In regions with permafrost, for example, thaw of permafrost can result in deepening of flowpaths that may bypass the rooting zone or intersect and export previously frozen soil nutrients. Thaw of permafrost might also result in evolution of new channel networks that redirect hydrologic connections between hillslopes and receiving streams, lakes, and coasts, or serve as efficient conduits for dissolved greenhouse gases to the atmosphere. A wide open question here is how changes in flowpaths might alter feedbacks between flowpaths and carbon or nutrient cycles.

Do you have a favorite ecohydrology paper? Describe/explain.
One of my favorite ecohydrological concepts is that biogeochemical reactions occur simultaneously with hydrologic transport. This is described by the “nutrient spiraling concept,” which was defined by stream ecologists. But this is not a stream-specific concept, as reaction and transport occur in all ecosystems. Wagener et al. (1998) point out the relevance of nutrient spiraling in soils, emphasizing differences in dominant spatial and temporal scales of transport relative to the scale of our observations in soils and streams.

Wagener, S., Oswood, M., & Schimel, J. (1998). Rivers and soils: parallels in carbon and nutrient processing. BioScience, 104–108.

What do you do for fun (apart from ecohydrology)?
Travel, explore new cities. I enjoy time with my child.

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MEET A LEAF: Teamrat A. Ghezzehei

MEET A LEAF: Fabrice Vinatier

MEET A LEAF: Jeannie Wilkening

MEET A LEAF: MATT COHEN

MEET A LEAF: TAMARA HARMS

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