EARTHSC 8898: Dr. Allen Hunt – An integrative approach to hydrology, soils, and ecology using percolation on networks and optimality

January 19, 2024

1:45PM - 2:30PM

Mendenhall Laboratory Room 291 and Zoom

Add to Calendar 2024-01-19 13:45:00 2024-01-19 14:30:00 EARTHSC 8898: Dr. Allen Hunt – An integrative approach to hydrology, soils, and ecology using percolation on networks and optimality Dr. Allen HuntProfessor, Department of Physics at Wright State UniversityDayton, OhioEmail: allen.hunt@wright.edu Host: Yanlan LiuLocation: Mendenhall Laboratory Room 291 or online using this Zoom link An integrative approach to hydrology, soils, and ecology using percolation on networks and optimalityIn the 19th century, Alexander von Humboldt noticed a strong dependence of plant species richness on latitude, a result that has been interpreted in terms of the latitudinal gradient of vegetation productivity. In 1943, Jenny proposed the soil forming factors equation (borrowed from the 19th century Russian Dokuchaev), S = S(cl,o,r,p,t), but without a concrete functional form. In 1997, Ryan published that “an understanding of the spatial and temporal variability of tree growth has eluded ecologists and tree physiologists.” In 1958, Odum wrote that maximization of the net primary productivity should guide the evolution of plant ecosystems. In 1991, the Committee on Hydrologic Sciences (CoHS) in a publication (NAS/NRC 1991) supporting the founding of the Hydrologic Sciences Program in EAR at NSF and stating that its purpose was “to provide a scientific framework and research agenda for scientists, educators, and students making career plans in the hydrologic sciences,” proposed a multi-pronged approach to solving the water balance P (precipitation) = Q (run-off) + ET (evapotranspiration), based on spatiotemporal scaling relations, ecological optimality (maximum assimilation of carbon), a theoretical construct where the hydrologic fluxes are the framework for the carbon fluxes, and limitations to the results from energy and water are addressed. I will show how finding a scaling relationship for soil formation from chemical weathering limited by solute transport and its associated water flux, Q, can be put together with a scaling relationship for vegetation growth and its associated flux, ET, to generate an expression for the net primary productivity, which is in the form of a product of a function of ET and a function of Q = (P – ET), which can be maximized to yield the water balance, the “central problem of hydrology.” Adding in energy- and water-limitations generates the observed water balance, streamflow elasticity, the climate variable dependence of NPP, and the latitudinal gradient of species richness. The scaling relationships also solve the puzzles presented by Jenny and Ryan. The solution method turns out to be identical to that of the CoHS report, and the implied maximization of species diversity with maximum NPP provides a framework to understand two of the fundamental problems of ecology. Dr. Allen HuntAllen received his PhD in the physics of disordered systems from the University of California, Riverside, in 1983 but worked mostly in part-time and temporary positions until 2004, when he came to Wright State University, split between the Geology and the Physics Departments. During these 20 years, he worked for two years as a Fulbright Scholar on semiconductor physics in Germany (1985-1987), returned to school at Duke University and earned an M.A. in geomorphology, 1995-1996 based on fieldwork on hillslope processes in the Mojave Desert, had postdoctoral experience in subsurface and surface hydrology, and was a visiting scientist in climate dynamics at PNNL from 1999-2002. His last position before he came to Wright State was as program director in hydrologic sciences at the National Science Foundation. He has done pioneering work in climate changes on the solid earth (influences of ENSO on East Pacific Rise seismicity 1999, and continental ice sheets on co-seismic crustal deformation, 1998) in addition to his main field of activity, involving percolation theory applied to network models of porous media. He has over 150 refereed publications, including in Nature, AGU Advances, and Reviews of Geophysics, as well as five different books, two of which have gone through multiple editions and have been a "top author" for AGU in 2021 and 2023. His most recent research has combined ecological optimality with percolation theory to generate an accurate predictive theory of the water balance. Mendenhall Laboratory Room 291 and Zoom OSU ASC Drupal 8 ascwebservices@osu.edu America/New_York public

2024-01-19 13:45:00 2024-01-19 14:30:00 EARTHSC 8898: Dr. Allen Hunt – An integrative approach to hydrology, soils, and ecology using percolation on networks and optimality  Dr. Allen HuntProfessor, Department of Physics at Wright State UniversityDayton, OhioEmail: allen.hunt@wright.edu Host: Yanlan LiuLocation: Mendenhall Laboratory Room 291 or online using this Zoom link An integrative approach to hydrology, soils, and ecology using percolation on networks and optimalityIn the 19th century, Alexander von Humboldt noticed a strong dependence of plant species richness on latitude, a result that has been interpreted in terms of the latitudinal gradient of vegetation productivity. In 1943, Jenny proposed the soil forming factors equation (borrowed from the 19th century Russian Dokuchaev), S = S(cl,o,r,p,t), but without a concrete functional form. In 1997, Ryan published that “an understanding of the spatial and temporal variability of tree growth has eluded ecologists and tree physiologists.” In 1958, Odum wrote that maximization of the net primary productivity should guide the evolution of plant ecosystems. In 1991, the Committee on Hydrologic Sciences (CoHS) in a publication (NAS/NRC 1991) supporting the founding of the Hydrologic Sciences Program in EAR at NSF and stating that its purpose was “to provide a scientific framework and research agenda for scientists, educators, and students making career plans in the hydrologic sciences,” proposed a multi-pronged approach to solving the water balance P (precipitation) = Q (run-off) + ET (evapotranspiration), based on spatiotemporal scaling relations, ecological optimality (maximum assimilation of carbon), a theoretical construct where the hydrologic fluxes are the framework for the carbon fluxes, and limitations to the results from energy and water are addressed.  I will show how finding a scaling relationship for soil formation from chemical weathering limited by solute transport and its associated water flux, Q, can be put together with a scaling relationship for vegetation growth and its associated flux, ET, to generate an expression for the net primary productivity, which is in the form of a product of a function of ET and a function of Q = (P – ET), which can be maximized to yield the water balance, the “central problem of hydrology.” Adding in energy- and water-limitations generates the observed water balance, streamflow elasticity, the climate variable dependence of NPP, and the latitudinal gradient of species richness. The scaling relationships also solve the puzzles presented by Jenny and Ryan. The solution method turns out to be identical to that of the CoHS report, and the implied maximization of species diversity with maximum NPP provides a framework to understand two of the fundamental problems of ecology. Dr. Allen HuntAllen received his PhD in the physics of disordered systems from the University of California, Riverside, in 1983 but worked mostly in part-time and temporary positions until 2004, when he came to Wright State University, split between the Geology and the Physics Departments. During these 20 years, he worked for two years as a Fulbright Scholar on semiconductor physics in Germany (1985-1987), returned to school at Duke University and earned an M.A. in geomorphology, 1995-1996 based on fieldwork on hillslope processes in the Mojave Desert, had postdoctoral experience in subsurface and surface hydrology, and was a visiting scientist in climate dynamics at PNNL from 1999-2002. His last position before he came to Wright State was as program director in hydrologic sciences at the National Science Foundation. He has done pioneering work in climate changes on the solid earth (influences of ENSO on East Pacific Rise seismicity 1999, and continental ice sheets on co-seismic crustal deformation, 1998) in addition to his main field of activity, involving percolation theory applied to network models of porous media. He has over 150 refereed publications, including in Nature, AGU Advances, and Reviews of Geophysics, as well as five different books, two of which have gone through multiple editions and have been a "top author" for AGU in 2021 and 2023. His most recent research has combined ecological optimality with percolation theory to generate an accurate predictive theory of the water balance. Mendenhall Laboratory Room 291 and Zoom America/New_York public

Dr. Allen Hunt
Professor, Department of Physics at Wright State University
Dayton, Ohio
Email: allen.hunt@wright.edu
Host: Yanlan Liu

Location: Mendenhall Laboratory Room 291 or online using this Zoom link

An integrative approach to hydrology, soils, and ecology using percolation on networks and optimality

In the 19^th century, Alexander von Humboldt noticed a strong dependence of plant species richness on latitude, a result that has been interpreted in terms of the latitudinal gradient of vegetation productivity. In 1943, Jenny proposed the soil forming factors equation (borrowed from the 19^th century Russian Dokuchaev), S = S(cl,o,r,p,t), but without a concrete functional form. In 1997, Ryan published that “an understanding of the spatial and temporal variability of tree growth has eluded ecologists and tree physiologists.” In 1958, Odum wrote that maximization of the net primary productivity should guide the evolution of plant ecosystems. In 1991, the Committee on Hydrologic Sciences (CoHS) in a publication (NAS/NRC 1991) supporting the founding of the Hydrologic Sciences Program in EAR at NSF and stating that its purpose was “to provide a scientific framework and research agenda for scientists, educators, and students making career plans in the hydrologic sciences,” proposed a multi-pronged approach to solving the water balance P (precipitation) = Q (run-off) + ET (evapotranspiration), based on spatiotemporal scaling relations, ecological optimality (maximum assimilation of carbon), a theoretical construct where the hydrologic fluxes are the framework for the carbon fluxes, and limitations to the results from energy and water are addressed.

I will show how finding a scaling relationship for soil formation from chemical weathering limited by solute transport and its associated water flux, Q, can be put together with a scaling relationship for vegetation growth and its associated flux, ET, to generate an expression for the net primary productivity, which is in the form of a product of a function of ET and a function of Q = (P – ET), which can be maximized to yield the water balance, the “central problem of hydrology.” Adding in energy- and water-limitations generates the observed water balance, streamflow elasticity, the climate variable dependence of NPP, and the latitudinal gradient of species richness. The scaling relationships also solve the puzzles presented by Jenny and Ryan. The solution method turns out to be identical to that of the CoHS report, and the implied maximization of species diversity with maximum NPP provides a framework to understand two of the fundamental problems of ecology.

Dr. Allen Hunt

Allen received his PhD in the physics of disordered systems from the University of California, Riverside, in 1983 but worked mostly in part-time and temporary positions until 2004, when he came to Wright State University, split between the Geology and the Physics Departments. During these 20 years, he worked for two years as a Fulbright Scholar on semiconductor physics in Germany (1985-1987), returned to school at Duke University and earned an M.A. in geomorphology, 1995-1996 based on fieldwork on hillslope processes in the Mojave Desert, had postdoctoral experience in subsurface and surface hydrology, and was a visiting scientist in climate dynamics at PNNL from 1999-2002. His last position before he came to Wright State was as program director in hydrologic sciences at the National Science Foundation. He has done pioneering work in climate changes on the solid earth (influences of ENSO on East Pacific Rise seismicity 1999, and continental ice sheets on co-seismic crustal deformation, 1998) in addition to his main field of activity, involving percolation theory applied to network models of porous media. He has over 150 refereed publications, including in Nature, AGU Advances, and Reviews of Geophysics, as well as five different books, two of which have gone through multiple editions and have been a "top author" for AGU in 2021 and 2023. His most recent research has combined ecological optimality with percolation theory to generate an accurate predictive theory of the water balance.