Landscape Evolution Observatory
The Earth system consisting of air, water, soil, plants and microbes is a complex, interacting system. How do physical and biological processes interactively control the evolution of landscapes? How is water flowing through landscapes influenced by their evolution in time, and by climate change? How do biological communities organize and respond to landscape evolution and environmental change? These are some examples of the most important and complicated Earth system science questions reflecting the complex nature of the Earth system with so many interactive parts And they’re ones that the Landscape Evolution Observatory, a physical model to simplify the complex interactions by controlling parts of the system, was designed to help answer.
The Landscape Evolution Observatory (LEO) is the world’s largest laboratory experiment in the interdisciplinary Earth sciences. The experiment consists of three artificial landscapes contained within elaborate steel structures and located inside three adjacent bays within the University of Arizona – Biosphere 2. The landscapes are designed as experimental replicates; each has dimensions of 30-m length, 11-m width, an average slope of 10°, and is filled to a uniform depth of 1 m with crushed basalt rock that was extracted from a volcanic crater in northern Arizona. In their initial state, the landscapes consist of approximately 500 metric tons (more than 1 million pounds) of the crushed rock, which has a loamy sand texture. This initial condition will allow scientists to observe each step in the landscapes’ evolution—from purely mineral and abiotic substrate to living, breathing landscapes that will ultimately support microbial and vascular plant communities
Those observations are made possible by the array of more than 1800 sensors and sampling devices that are installed on, within, or above each landscape. The sensors enable monitoring of water, carbon, and energy cycling processes, and the physical and chemical evolution of the landscape at sub-meter to whole-landscape scales. As the soil, topography, and biological communities evolve to increasingly complex states, scientists will be able to document how those changes affect water, carbon, and energy cycling within the landscape, and between the landscape and the atmosphere.
Research at LEO will advance our understanding of how climate change may impact water resources and ecosystems in arid environments. This understanding will result from iterations of well-designed physical experiments with LEO and virtual experiments with mathematical models of coupled ecohydrological processes. Since LEO resides within the climate controlled Biosphere 2 facility, researchers can perform manipulative experiments to examine how the water, soil, plant, and microbes respond to diverse scenarios of climate (air temperature and rainfall) The climate control capabilities, well-defined system properties, and network of sensors make LEO an exceptional platform for developing and testing mathematical models (conceptual models) that simulate this ecohydrological responses—the types of models that can be used to infer how water resources and ecosystems in real landscapes may be impacted by ongoing and future climate change.
CO2 diffusion into pore spaces limits weathering rate of an experimental basalt landscape . van Haren, J., Dontsova, K., Barron-Gafford, G. A., Troch, P. A., Chorover, J., Delong, S. B., Breshears, D. D., Huxman, T. E., Pelletier J. D., Saleska, S. R., Xeng, X., and Ruiz, J. (2017): Geology 45(3): 203-206.
The mechanistic basis for storage-dependent age distributions of water discharged from an experimental hillslope . Pangle, L. A., Kim, M. Cardoso, C., Lora, M., Meira Neto, A. A., Volkmann, T. H. M., Wang, Y., Troch, P. A., and Harman, C. J. (2017): Water Resources Research 53: 2733–2754.
Methanotrophic bacterial diversity in two diverse soils under varying land-use practices as determined by high-throughput sequencing of the pmoA gene . Sengupta, A. and Dick, W. A. (2017): Applied Soil Ecology 119: 35-45.
Testing the hybrid-3-D hillslope hydrological model in a controlled environment . Hazenberg, P., Broxton, P., Gochis, D., Niu, G.-Y., Pangle, L. A., Pelletier, J. D., Troch, P. A., and Zeng X. (2016): Water Resources Research 52(2): 1089–1107.
Pore water chemistry reveals gradients in mineral transformation across a model basaltic hillslope . Pohlmann, M., Dontsova, K., Root, R., Ruiz, J., Troch, P., and Chorover, J. (2016): Geochemistry, Geophysics, Geosystems 17(6): 2054–2069.
The Effects of Rain on Elemental Transport in Soils . Schoenfeld, L.K., Hunt, E.A., Dontsova, K.M. (2016): STAR (STEM Teacher and Researcher) Program Posters.
Between control and complexity: opportunities and challenges for marine mesocosms . Sagarin, R.D., Adams, J., Blanchette, C.A., Brusca, R.C., Chorover, J., Cole, J.E., Micheli, F., Munguia-Vega, A., Rochman, C.M., Bonine, K., van Haren, J. and Troch, P.A. (2016): Frontiers in Ecology and the Environment 14(7): 389–396.
Soil Lysimeter Excavation for Coupled Hydrological, Geochemical, and Microbiological Investigations . Sengupta, A. Wang, Y., Meira-Neto, A.A., Matos, K.A., Dontsova, K., Root, R., Neilson, J.W., Maier, R.M., Chorover, J., and Troch, P.A. (2016): Journal of Visualized Experiments 115: e54536.
Multiresponse modeling of variably saturated flow and isotope tracer transport for a hillslope experiment at the Landscape Evolution Observatory . Scudeler, C., Pangle, L., Pasetto, D., Niu, G.-Y., Volkmann, T., Paniconi, C., Putti, M., and Troch, P. (2016): Hydrology and Earth System Sciences 20(10): 4061-4078.
Transit time distributions and StorAge Selection functions in a sloping soil lysimeter with time-varying flow paths: Direct observation of internal and external transport variability . Kim, M., Pangle, L. A., Cardoso, C., Lora, M., Volkmann, T. H. M., Wang, Y., Harman, C. J., and Troch, P. A. (2016): Water Resources Research 52(9): 7105-7129.
The Landscape Evolution Observatory: A large-scale controllable infrastructure to study coupled Earth-surface processes . Pangle, L.A., DeLong, S.B., Abramson, N., Adams, J., Barron-Gafford, G.A., Breshears, D.D., Brooks, P.D., Chorover, J., Dietrich, W.E., Dontsova, K., Durcik, M., Espeleta, J., Ferre, T.P.A., Ferriere, R., Henderson, W., Hunt, E.A., Huxman, T.E., Millar, D., Murphy, B., Niu, G-Y., Pavao-Zuckerman, M., Pelletier, J.D., Rasmussen, C., Ruiz, J., Saleska, S., Schaap, M., Sibayan, M., Troch, P.A., Tuller, M., van Haren, J., Zeng, X. (2015): Geomorphology 244: 190-203.
Impact of sensor failure on the observability of flow dynamics at the Biosphere 2 LEO hillslopes . Pasetto, D., Niu, G.-Y., Pangle, L., Paniconi, C., Putti, M., Troch, P. A. (2015): Advances in Water Resources 86: 327-339.
Seven Anion Comparison for the Center and West Hill Slope Systems in the Landscape Evolution Observatory (LEO) Project . Corrigan, S.C., Hunt, E.A., Dontsova, K.M. (2015): STAR (STEM Teacher and Researcher) Program Posters.
Mineral nutrient mobilization by plants from rock: influence of rock type and arbuscular mycorrhiza . Burghelea, C., Zaharescu, D. G., Dontsova, K., Maier, R., Huxman, T., Chorover J. (2015): Biogeochemistry 124(1): 187-203.
Monitoring and Modeling Water, Energy and Carbon Fluxes at the Hillslope Scale in the Landscape Evolution Observatory . Troch, P., Barron-Gafford, G., Dontsova, K., Fang, Y., Niu, G.-Y., Pangle, L., Tuller, M., Van Haren, J. (2014): Abstract H43L-1128 presented at 2014 Fall Meeting, AGU, San Francisco, CA, 15-19 Dec.
Reactive Transport Modelling of Mineral Evolution in the Biosphere 2 Hillslope Experiment . Wu, R., Niu, G.-Y., Steefel, C., Paniconi, C., Chorover, J., Dontsova, K., Troch, P. (2014): Abstract H53A-0843 presented at 2014 Fall Meeting, AGU, San Francisco, CA, 15-19 Dec.
Impact of organic carbon on weathering and chemical denudation of granular basalt . Dontsova, K., Zaharescu, D., Henderson, W., Verghese, S., Perdrial, N., Hunt, E., Chorover, J. (2014): Geochimica et Cosmochimica Acta 139: 508–526.
Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory . Niu, G.-Y., Pasetto, D., Scudeler, C., Paniconi, C., Putti, M., Troch, P. A., DeLong, S. B., Dontsova, K., Pangle, L., Breshears, D. D., Chorover, J., Huxman, T. E., Pelletier, J., Saleska, S. R., and Zeng, X. (2014): Hydrology and Earth System Sciences 18(5): 1873-1883.
Flow and transport modeling of a tracer isotope experiment at B2 LEO using integrated and distributed multisensor observation data . Scudeler, C., Pangle, L., Pasetto, D., Niu, G-Y., Paniconi, C., Putti, M., Troch, P. (2014): Abstract H13E-1165 presented at 2014 Fall Meeting, AGU, San Francisco, CA, 15-19 Dec.
Rapid CO2 consumption during incipient weathering of a granular basaltic hillslope in the Landscape Evolution Observatory, Biosphere 2 . Ruiz, J., Van Haren, J., Dontsova, K., Barron-Gafford, G., Troch, P., Chorover J. (2014): Abstract V23A-4778 presented at 2014 Fall Meeting, AGU, San Francisco, CA, 15-19 Dec.
Hillslope-scale experiment demonstrates the role of convergence during two-step saturation . Gevaert, A.I., Teuling, A.J., Uijlenhoet, R., DeLong, S.B., Huxman, T.E., Pangle, L.A., Breshears, D.D., Chorover, J., Pelletier, J.D., Saleska, S.R, Zeng, X., Troch, P.A. (2014): Hydrology and Earth System Sciences 18: 3681-3692.
Precipitation pulse dynamics of carbon sequestration and efflux in highly weatherable soils . Barron-Gafford, G., Minor, R., Van Haren, J.L., Dontsova, K., Troch, P.A. (2013): Abstract EP13C-0879 presented at 2013 Fall Meeting, AGU, San Francisco, CA, 9-13 Dec.
Hydrologic discovery through controlled experimentation, data analysis, and numerical and analytical modeling at the Landscape Evolution Observatory (Invited) . Troch, P. A., Gevaert, A., Smit, Y., Niu, G.-Y., Nakolan, L., Kyzivat, E. (2013): Abstract H11C-1167 presented at 2013 Fall Meeting, AGU, San Francisco, CA, 9-13 Dec.
Breakthroughs in Lab Experiments . Peter Troch (2013): GIWS Distinguished Lecture Series.
Hysteresis of soil moisture spatial heterogeneity and the “homogenizing” effect of vegetation . Ivanov, V.Y.,Fatichi, S., Jenerette, G.D., Espeleta, J.F., Troch, P.A., Huxman, T.E. (2010): Water Resources Reasearch 46(9): W09521.
The Hills are Alive: Interdisciplinary Earth Science at Biosphere 2 . Huxman, T., Troch, P., Chorover, J., Breshears, D.D., Saleska, S., Pelletier, J., Zeng, X. (2009): EOS 90(14): 120.
Solid phase evolution in the Biosphere 2 hillslope experiment as predicted by modeling of hydrologic and geochemical fluxes . Dontsova, K., Steefel, C.I., Desilets, S., Thompson, A., Chorover, J. (2009): Hydrology and Earth System Sciences 13: 2273-2286..
Hillslope hydrology under glass: Confronting fundamental questions of soil-water-biota co-evolution at Biosphere 2 . Hopp, L., Harman, C., Desilets, S. L.E., Graham, C. B., McDonnell, J. J., Troch, P. A. (2009): Hydrology and Earth System Sciences 13: 2105–2118.