Betty and Isaac Barshad Professor, Emeritus
B.S. Agriculture 1961 University of Arizona
M.S. Soil Physics 1963 University of Arizona
Ph.D. Soil Science 1965 University of California at Berkeley
Professor Sposito teaches Introduction to Environmental Studies with English professor Robert Hass and an undergraduate course, Green Water, Brown Ground, and Global Food Security, on the role of soil and water resources in meeting future world food demand.
Aqueous geochemistry, especially surface chemistry and colloidal behavior; subsurface hydrology, particularly soil water behavior; mathematical models of transport in porous media; molecular simulations of geochemical systems.
Sposito, G. 2008. Geochemistry in Soil Science. In W. Chesworth (ed.), Encyclopedia of Soil Science, pp. 283-289. Springer, New York.
Sposito, G. 2008. The Chemistry of Soils. 2nd Ed. Oxford University Press, New York. 330 p.
Kwon, K. D., K. Refson, and G. Sposito. 2008. Defect-induced photoconductivity in layered manganese oxides: A density functional theory study. Phys. Rev. Lett. 100:146601 (4 pp).
Bourg, I. C., and G. Sposito. 2008. Isotopic fractionation of noble gases by diffusion in liquid water. Geochim. Cosmochim. Acta. 72:2237.
Bourg, I. C., G. Sposito, and A. C. M. Bourg. 2008. Modeling the diffusion of Na+ in compacted water-saturated Na-bentonite as a function of pore water ionic strength. Appl. Geochem. 23:3635.
Duckworth, O. W., J. R. Bargar, and G. Sposito. 2008. Sorption of ferric iron from ferrioxamine B to synthetic and biogenic layer type manganese oxides. Geochim. Cosmochim. Acta 72:3371.
Aristilde, L., and G. Sposito. 2008. Molecular modeling of metal complexation by a fluoroquinolone antibiotic. Environ. Toxicol. Chem. 27:2304.
Rakshit, S., M. Uchimiya, and G. Sposito. 2009. Iron(III) bioreduction in soil in the presence of added humic substances. Soil Sci. Soc. Am. J. 73:65.
Duckworth, O. W., S. J. M. Holmström, J. Peña, and G. Sposito. 2009. Biogeochemistry of iron oxidation in a circumneutral freshwater habitat. Chem. Geol. 260:149.
Lo, W.-C., G. Sposito, and E. Majer. 2009. Analytical decoupling of poroelasticity equations for acoustic wave propagation and attenuation in a porous medium containing two immiscible fluids. J. Engin. Math. 64:219.
Duckworth, O. W., J. Bargar, and G. Sposito. 2009. Quantitative structure-activity relationships for aqueous metal-siderophore complexes. Environ. Sci. Technol. 43:343.
Kwon, K. D., K. Refson, and G. Sposito. 2009. Zinc surface complexes on birnessite: A density functional theory study. Geochim. Cosmochim. Acta 73:1273.
Duckworth, O. W., J. R. Bargar, A. A. Jarzecki, O. Oyerinde, T. G. Spiro, and G. Sposito. 2009. The exceptionally stable Co(III)-desferrioxamine B complex. Marine Chem. 113:114.
Duckworth, O. W., J. Bargar, and G. Sposito. 2009. Coupled biogeochemical cycling of iron and manganese as mediated by microbial siderophores. Biometals 22:605.
Kwon, K.D., K. Refson, and G. Sposito. 2009. On the role of Mn(IV) vacancies in the photoreductive dissolution of hexagonal birnessite. Geochim. Cosmochim. Acta 73:3981.
Spiro, T. G., J. R. Bargar, G. Sposito, and B. M. Tebo. 2010. Bacteriogenic manganese oxides. Acc. Chem. Res. 43:2.
Aristilde, L., and G. Sposito. 2010. Binding of Ciprofloxacin by humic substances: A molecular dynamics study. Environ. Toxicol. Chem. 44:1444.
Aristilde, L., L. Melis, and G. Sposito. 2010. Inhibition of photosynthesis by a fluoroquinolone antibiotic. Environ. Sci. Technol. 44:1444.
Lo, W.-C., G. Sposito, E. Majer, and C.-L. Yeh. 2010. Motional modes of dilatational waves in elastic porous media containing two immiscible fluids. Advan. Water Resour. 33:304.
Bourg, I. C., F. M. Richter, J. N. Christensen, and G. Sposito. 2010. Isotopic mass-dependence of metal cation diffusion coefficients in liquid water. Geochem. Cosmochim. Acta 74:2249.
Bourg, I. C., and G. Sposito. 2010. Connecting the molecular scale to the continuum scale for diffusion processes in smectite-rich porous media. Environ. Sci. Technol. 44:2085.
Peña, J., K. D. Kwon, K. Refson, J. R. Bargar, and G. Sposito. 2010. Mechanisms of nickel sorption by a bacteriogenic birnessite. Geochem. Cosmochim. Acta 74:3076.
Kwon, K. D., and G. Sposito. 2010. Reactivity of biogenic manganese oxide for metal sequestration and photochemistry: Computational solid state physics study. J. Miner. Soc. Korea 23:161. (in Korean)
Kwon, K. D., K. Refson, and G. Sposito. 2010. Surface complexation of Pb(II) by hexagonal birnessite nanoparticles. Geochem. Cosmochim. Acta 74:6731.
Kwon, K. D., K. Refson, S. Bone, R. Qiao, W. Yang, Z. Liu, and G. Sposito. 2011. Magnetic ordering in mackinawite (tetragonal FeS): Evidence for strong itinerant spin fluctuations. Phys. Rev. B. 83:064402.
Bourg, I., and G. Sposito. 2011. Molecular dynamics simulations of the electrical double layer on smectite surfaces contacting concentrated mixed electrolyte (NaCl-CaCl2) solutions. J. Colloid Interface Sci. 360:701.
Sposito, G. 2011. Electron shuttling by natural organic matter: Twenty years after. In P. Tratnyek, T. Grundl, and S. Haderlein (eds.), Aquatic Redox Chemistry, Chap. 5. ACS Symposium Series, American Chemical Society, Washington, DC.
Peña, J., J. Bargar, and G. Sposito. 2011. Role of bacterial biomass in the sorption of Ni by biomass-birnessite assemblages. Environ. Sci. Technol. 45:7338.
Bourg, I. C., and G. Sposito. 2012. Ion Exchange Phenomena. In P. M. Huang, Y. Li, and M. E. Sumner (eds.), Handbook of Soil Sciences, 2nd Ed., Chap. 16. CRC Press, Boca Raton, FL.
Lo, W-C, G. Sposito, and Y-H Huang. 2012. Modeling seismic stimulation: Enhanced non-aqueous fluid extraction from saturated porous media under pore-pressure pulsing at low frequencies. J. Appl. Geophys. 78:77.
Nielsen, L. C., I. C. Bourg, and G. Sposito. 2012. Predicting CO2-water interfacial tension under pressure and temperature conditions of geologic CO2 storage. Geochim. Cosmochim. Acta 81:28.
Harrington, J. M., D. L. Parker, J. R. Bargar, A. A. Jarzecki, B. M. Tebo, G. Sposito, and Owen Duckworth. 2012. Structural dependence of Mn complexation by siderophores: Donor group dependence on complex stability and reactivity. Geochim. Cosmochim. Acta 88:106.
Kwon, K. D., K. Refson, and G. Sposito. 2013. Understanding the trends in transition metal sorption by vacancy sites in birnessite. Geochim. Cosmochim. Acta 101:222.
Aristilde, L., and G. Sposito. 2013. Complexes of the antimicrobial Ciprofloxacin with soil, peat, and aquatic humic substances. Environ. Toxicol. Chem. 32:1467.
Sposito, G. 2013. Green water and global food security. Vadose Zone J.. 12:doi:10.21.36/vzj2013.02.0041.
Amundson, R., and G. Sposito. 2013. Bridging the divide: Soil resources and the geosciences on a cultivated planet. In Bickford, M. E., (ed.), The Impact of the Geological Sciences on Society. Geological Society of America Special Paper 501, pp. 69-80.
Lo, W.-C., and Sposito, G. 2013. Acoustic waves in unsaturated soils. Water Resour. Res. 49:5674.
Sposito, G. 2014. Sustaining "the genius of soils." In G. Churchman and E. R. Landa (eds.), The Soil Underfoot: Infinite possibilities for a finite resource. CRC Press, Boca Raton, FL, pp. 395-408.
Lo, W.-C., G. Sposito, and H. Chu. 2014. Poroelastic theory of consolidation in unsaturated soils. Vadose Zone J. 13: doi:10.2136/vzj2013.07.0117.
Senior Fulbright Lecturer in Theoretical Solid-State Physics (University of Córdoba, Argentina)
Guggenheim Fellow (Applied Mathematics, University of Oxford)
NATO-Heinemann Senior Fellow (Chemistry, National Institute of Agronomic Research, Versailles, France)
Fellow: American Geophysical Union, American Society of Agronomy, European Association of Geochemistry, Geochemical Society, International Union of Pure and Applied Chemistry, and Soil Science Society of America
Foreign Member, Academy of Agriculture of France
Soil Science Research Award, Soil Science Society of America
Hydrologic Sciences Award, American Geophysical Union
Distinguished Teaching Award, Sonoma State University
Distinguished Teaching Award, University of California at Riverside
Distinguished Teaching Award, College of Natural Resources, University of California at Berkeley
Teaching Excellence Laureate, Phi Beta Kappa
Faculty Award for Outstanding Mentoring of GSIs, University of California at Berkeley
Miller Research Professor, University of California at Berkeley
"Landmark" Paper Award, Association of Environmental Engineering and Science Professors
Walter J. Weber, Jr. Distinguished Lecture in Environmental Sciences and Engineering, University of Michigan
Highly-cited Researcher, Ecology and Environment, Institute for Scientific Information
Horton Medal, American Geophysical Union
"Physical Chemistry of Soils and Aquifers," Special Symposium of the American Chemical Society
and Special Issue of Geochimica et Cosmochimica Acta (656 KB Adobe PDF)
Designated a "Legend of Environmental Chemistry," American Chemical Society (95 KB Adobe PDF)
Hans Jenny Memorial Lecture in Soil Science, University of California at Berkeley
Langbein Lecture, American Geophysical Union
Soils are open, multicomponent, biogeochemical systems containing solids, liquids, and gases. That they are open systems means soils exchange both matter and energy with the surrounding atmosphere, biosphere, and hydrosphere. These flows of matter and energy to or from soils are highly variable in time and space, but they are the essential fluxes that cause the development of soil profiles and govern soil health.
It is widely understood that crop production must increase at least twice as fast as human population growth during the coming 40 years to meet global food demand. Tested strategies for achieving this goal have not yet emerged, but two stipulations to guide the search for them can be made: Adverse ecological impacts of land conversion to agricultural use and freshwater withdrawals for irrigation will strongly limit the viability of these two traditional approaches to increasing crop production, whereas abundant opportunity exists for optimizing soil water availability to and consumption by crops to increase their yields.
Research in aqueous geochemistry has long benefited from insights provided by molecular simulations. The underlying philosophy of these simulations is to construct a mathematical description of molecular interactions, then solve the resulting equations for a system of molecules in order to predict its properties. Simulations are critical to a fundamental understanding of the surface and colloid chemistry of natural nanoparticles. A description of recent research results and publications is given on the simulations web site of the Earth Sciences Division at Lawrence Berkeley National Laboratory.
- Structure and reactivity of layer type minerals
- Soil water and global food security
- Poroelastic behavior of soils and sediments