Faculty Directory - Ohno
Research Area: Organic Matter Chemistry, Phosphorus Soil Chemistry,
Office: 103 Deering Hall
Bio: Dr. Ohno received his B.S. degree in Chemistry from Kansas State University in 1977. He received a M.S. (1981) and Ph.D. (1983) in Soil Science from Cornell University. He joined the faculty in 1987. He is currently a Professor of Soil Chemistry.
Teaching: PSE546 Chemistry of Soils; PSE580 Scientific Communications I; PSE581 Scientific Communications II
My current research efforts focus on (1) chemically characterizing soil organic matter and (2) determining the molecular-level chemical mechanisms governing dissolved organic matter and phosphorus reactions with soil mineral surfaces. Interest in carbon cycling in soils has recently increased greatly due to the effects of both carbon dioxide and methane on global climate. Carbon sequestration in soils has been proposed as a strategy to moderate increasing levels of both gasses in the atmosphere. Understanding the chemistry of soil organic matter is important for understanding the factors that stabilize carbon in soils. In addition, this knowledge is key to understanding biogeochemical mechanisms of phosphorus cycling through both agricultural and forested ecosystems. These studies will contribute to a more accurate understanding of how management systems can be used to enhance the bio-availability of phosphorus and reduce adverse environmental impacts due to excessive phosphorus loading to soils.
My core research has been funded through a series of USDA competitive grants that I have received during my tenure here at the University of Maine. I use a range of chemical methodologies including fluorescence, infrared, NMR, ESI-FT-ICR mass spectrometry, and atomic force microscopy to determine the chemical nature of soil organic matter and the mechanisms for its bonding to soil surfaces. In addition, I link my laboratory studies to field- and watershed-scale processes by collaborating with other scientists and using soil and plant samples from an extensively monitored and characterized cropping system study site, and an equally well-studied forest watershed manipulation site. Because my molecular-scale data is generated using samples from well-characterized field scale studies, results can be used to understand both carbon and phosphorus cycling in a context which is relevant to optimizing management practices to conserve both carbon and phosphorus in agricultural and forested environments.
The most-recent USDA-NRI funded grant continues the work on the use of ultrahigh resolution mass spectrometry to characterize organic matter which we have demonstrated as an ideal analytical method to study the chemical structure of organic matter. We have also added atomic force microscopy to directly map the spatial arrangement of organic matter adsorbed to mineral surfaces and to probe how changing chemical environment affects the bond strength between organic matter and the surface using force measurements. Atomic force microscopy allows direct measurement and visualization of molecules adsorbed to surfaces and will be an important advancement in soil surface chemistry. My section of an ongoing NSF grant is to use ultrahigh resolution mass spectrometry to identify the functional types of compounds which contain the labeled nitrogen as it moves through the ecosystem.
Ohno, T., T.B. Parr, M.-C.I. Gruselle, I.J. Fernandez, R.L. Sleighter, and P.G. Hatcher. 2014. Molecular Composition and Biodegradability of Soil Organic Matter: A Case Study Comparing Two New England Forest Types. Environ. Sci. Technol. 48:7229-7236.
Parr, T.B., T.Ohno, K.S. Simon, C.S. Cronan. 2014. comPARAFAC: A library and tools for rapid and quantitative comparison of dissolved organic matter components resolved by PARAFAC analysis. Limnol. Oceanogr. Methods. 12:114-125.
Uchimiya, S., T. Ohno, and Z. He. 2013. Pyrolysis temperature-dependent release of dissolved organic carbon from plant, manure, and biorefinery wastes. J. Anal. Appl. Pyrolysis 104:84-94.
Ohno, T., and N. Severy. 2013. Effects of organic and conventional management systems on the phosphorus solubility of lowbush blueberry barren soils. Soil Use Manage. 29:485-493.
He, Z., X.Y. Cao, J.D. Mao, T. Ohno, and H.M. Waldrip. 2013. Analysis of carbon functional groups in mobile humic acid and recalcitrant calcium humate extracted from eight U.S. soils. Pedosphere 23:705-716.
Lannan, A.P., M.S. Erich, and T. Ohno. 2013. Compost feedstock and maturity level affect soil response to amendment. Bio. Fert. Soils 49:273-285.
Ohno, T., and P.E. Ohno. 2013. Influence of heteroatom pre-selection on the molecular formula assignment of soil organic matter components determined by ultrahigh resolution mass spectrometry. Anal. Bioanal. Chem. 405:3299-3306
Mineau, M.M., C.M. Rigsby, D.T. Ely, I.J. Fernandez, S.A. Norton, T. Ohno, and K.S. Simon. 2013. Chronic catchment nitrogen enrichment and stoichiometric constraints on the bioavailability of dissolved organic matter from leaf leachate. Freshwater Biol. 58:248-260.
Raymond, J.E., I.J. Fernandez, T. Ohno, and K. Simon. 2013. Soil drainage class influences on soil carbon in a New England Forested Watershed. Soil Sci. Soc. Am. J. 77:307-317.
He, Z., and T. Ohno. 2012. Fourier transform infrared and fluorescence spectral features of organic matter in conventional and organic dairy manure. J. Environ. Qual. 41:911-919.
Erich, M.S., A.F. Plante, J.M. Fernandez, E.B. Mallory, and T. Ohno. 2012. Profile depth and management alter soil organic matter storage and chemistry. Soil Sci. Soc. Am. J. 76:408-419
Ohno, T., S. Hiradate, and Z. He. 2011. Phosphorus solubility of agricultural soils: A surface charge and phosphorus-31 NMR speciation study. Soil Sci. Soc. Am. J. 75:1704-1711.
Ohno, T., Z. He, R.L. Sleighter, and P.G. Hatcher. 2010. Ultrahigh resolution mass spectrometry and indicator species analysis to identify marker components of soil- and plant biomass-derived organic matter fractions. Environ. Sci. Technol. 44:8594-8600.
Simon, K.S., T. Pipan, T. Ohno, and D.C. Culver. 2010. Spatial and temporal patterns in abundance and character of dissolved organic matter in two karst aquifers. Fundamental Appl. Limnol. 177:81-92.
He, Z., T. Ohno, D.C. Olk, and F. Wu. 2010. Capillary electrophoresis profiles and fluorophore components of humic acids in Nebraska corn and Philippine rice soils. Geoderma 156:143-151..
Ohno, T., and A. Amirbahman. 2010. Phosphorus availability in boreal forest soils: A geochemical and nutrient uptake modeling approach. Geoderma 155:46-54.