Xiahong Feng Stable Isotope Geochemistry and Hydrochemistry

Contact Information:

Overview of Research:

The main feature of my research is the interdisciplinary approach to global and local environmental problems. I use major and trace element concentrations and variations of stable isotopic ratios of oxygen, hydrogen, carbon and nitrogen in natural materials, such as rocks, water, tree-rings, soils and air, to study the function and dynamics of natural systems, to trace the history of the climatic and environmental changes and to understand the mechanisms for such changes. Recent projects include solute and contaminant transport in watersheds or in snow and their effects on stream chemistry, rates and mechanisms of plant and soil organic matter decomposition and the implications to the global carbon cycle, and reconstruction of paleohumidity using oxygen and hydrogen isotopic compositions of tree rings. These research topics are discussed in more detail below:

• Hydrogen and oxygen isotope studies of tree rings
• Oxygen and hydrogen isotopic compositions in leaf water
• Study of plants’ water used efficiency using C isotopes of tree rings
• Carbon and nitrogen cycles in plant-soil systems
• Isotope hydrology and hydrochemistry

Research Group Website: Stable Isotopes Laboratory

Selected Recent Publications:

1. Lennon *, J.T. Faiia, A.M. Feng, X., Cottingham, K.L. (2006) Evidence for CO 2 recycling in lakes along a terrestrial carbon gradient, Limnology and Oceanography, 51(4), 1602-1613.
2. Liu, W., Feng, X., Ning, Y., Zhang, Q., Cao, Y., and An, Z. (2005) d 13C variation of C 3 and C 4 plants across an Asian monsoon rainfall gradient in arid northwestern China, Global Change Biology, 11, 1094-1100.
3. Shu *, Y., Feng, X., Gazis, C., Anderson, D. Faiia *, A.M., Tang *, K., Ettl, G.J. (2005) Relative humidity recorded in tree rings: a study along a precipitation gradient in the Olympic Mountains, Geochimica et Comochimica Acta, 69, 791-799.
4. Posmentier, E.S. Feng, X., Zhao, M. (2004) Seasonal variations of precipitation d 18O in Eastern Asia, Journal of Geophysical Research, 109, D23106, doi:10.1029/2004JD004510.
5. Poage *, M.A. and Feng, X. (2004) A theoretical model of steady state d 13C vs. depth profiles of decomposing soil organic matter. Global Biogeochemical Cycles. 18, GB2016, doi:10.1029/2003GB002195.
6. Feng, X., Kirchner, J.W., and Neal, C. (2004) Measuring catchment-scale chemical retardation using spectral analysis of reactive and passive chemical tracer time series, Journal of Hydrology, 292, 296-307.
7. Renshaw, C.E. Feng, X. Sinclair *, K.J. and Dums *, R.H.R. (2003) The use of stream flow routing for direct channel precipitation with isotopically-based hydrograph separations: the role of new water in stormflow generation. Journal of Hydrology, 273, 205-216.
8. Feng, X. (2002) A theoretical analysis of carbon isotope evolution of decomposing plant litters and soil organic matter. Global Biogeochemical Cycles, 16(4), Art. No.1119, doi:10.1029/2002GB001867.
9. Kirchner, J.W., Feng X. and Neal, C. (2000) Fractal stream chemistry and its implication for contaminant transport in catchments. Nature, 403, 524-527.

Complete CV