Ronald Amundson

Professor
Ph.D.  
  

317 Hilgard Hall
Berkeley, California 94720
earthy@nature.berkeley.edu
office: 510-643-7890   lab: 510-643-7890   fax:  510-643-5438

     Recent publications      People

Our current research focuses on the general themes of (1) the effect of climate on the long-term biogeochemical development of soils and landform evolution, (2) the processes of ecosystem carbon and nitrogen cycling, and (3) ways of developing improved means of dating soils and landscapes, using a combination of stable and radioactive isotope geochemistry.

Isotopes are an important tool in our research. We use natural levels of ¹⁴C and ¹³C/¹²C in soil organic matter to understand how climate and soil age control natural rates of soil carbon cycling . We use ¹⁴N/¹⁵N and ¹⁸O/¹⁶O and ¹⁷O/¹⁶O to understand the sources and sinks of total soil N, nitrate, and N²O. We also use ³⁴S/³²S to examine the origin and cycling of gypsum in desert soils. C and O isotopes in soil and biogenic carbonate are used to better understand past vegetation and rainfall sources. Much of the sample preparation is done in our lab, and the analyses of prepared samples is done at the Berkeley Center for Isotope Biogeochemistry, and with the help and collaboration of colleagues both at Berkeley and elsewhere: Professor Kristie Boering (UCB), Dr. Carol Kendall (USGS), and Professor Mark Thiemens (UCSD).

Atacama Desert, Chile: We are collaborating with NASA investigators to study the biology and chemistry of soils in extreme environments, to examine the evolution of hillslopes and fluvial features, and to better understand (through earth analogues) the past (or present) biogeochemistry of Mars. Key collaborators include Dr. Kuni Nishiizumi (Space Sciences Laboratory) and Prof. William Dietrich (UCB).

California and Australia: We are examining the rates at which organic C is eroded from upland landscapes, and its role in the local and global C cycles. Secondly, we are examining the relative rates of physical vs. chemical erosion on these landscapes. Key collaborators include Prof. Arjun Heimsath (Dartmouth College) and Prof. William Dietrich (UCB).

California: We are involved in a study to examine the effect of rainfall and vegetation on the rates (and importance) of dissolved organic C losses from upland watersheds in coastal California. Key collaborators include Prof. David Brown (Chico State Univ.) and Prof. William Dietrich (UCB).

California and Hawaii: We are developing ways of using position-specific N isotope compositions to determine the pathways of N2O formation in soils - both in laboratory experiments and in the field. Key collaborators include Prof. Mary Firestone (UCB) and Prof. Kristie Boering (UCB).

Wind River Basin, Wyoming: We are collaborating with colleagues from UC Santa Barbara and the Berkeley Geochronology Institute to develop U/Th isotope techniques to date the soils and landscapes of the Wind River Basin. We are also developing a long term paleoclimate perspective through a combination of dating and stable isotope analyses.

1. Stern, L., T. Baisden, and R. Amundson. 1999. Processes controlling the oxygen isotope ratio of soil CO2: analytic and numerical modeling. Geochemica et Cosmochimica Acta 63:799-814.

2. Wang, Y., R. Amundson, and S. Trumbore. 1999. The impact of land use change on C turnover in soils. Global Biogeochemical Cycles 13:47-57.

3. Wang, Y., R. Amundson, and X-F. Niu. Seasonal and altitudinal variation in decomposition of soil organic matter inferred from radiocarbon measurements of soil CO2 flux. Global Biogeochemical Cycles 14:199-211.

4. Arens, N.A., A.H. Jahren, and R. Amundson. 2000. Can C3 plants faithfully record the carbon isotope composition of atmospheric carbon dioxide? Paleobiology 26:137-164.

5. Davidson, EA., S.E. Trumbore, and R. Amundson. 2000. Soil warming and the organic carbon budget. Nature. 408:789-790.

6. Gadbury, C. L. Todd, A.H. Jahren, and R. Amundson. 2000. Spatial and temporal variations in the isotopic composition of bison tooth enamel from the Early Holocene Hudson-Meng Bone Bed, Nebraska. Palaeogeography, Palaeoclimatology, and Palaeoecology. 157(1-2):79-93.

7. Jahren, A.H., N.C. Arens, G. Sarmiento, J. Guerero, and R. Amundson. 2001.Terrestrial record of methane hydrate dissociation in the early Cretaceous. Geology 29:159-162..

8. Amundson, R. 2001. The Soil Carbon Cycle. Annual Reviews of Earth and Planetary Sciences. 29:535-562.

9. Stern, L., R. Amundson, and T. Baisden. 2001. The influence of soils on oxygen isotope ratio of atmospheric CO2. Global Biogeochemical Cycles 15:753-759.

10. Jahren, A.H., R. Amundson, C. Kendall, and P. Wigand. 2001. Paleoclimate reconstruction using the correlation in d18O of hackberry carbonate and environmental water, North America. Quaternary Research 56:252-263.

11. Brenner, D.L., R. Amundson, W.T. Baisden, C. Kendall, and J. Harden. 2001. Soil N and 15N variation with time in a California annual grassland ecosystem. Geochimica et Cosmochimica Acta 65:4171-4186.

12. Baisden, W.T., R. Amundson, D.L. Brenner, A.C. Cook, C. Kendall, and J. Harden. 2002. A multi-isotope C and N modeling analysis of soil organic matter turnover and transport as a function of soil depth in a California annual grassland. Global Biogeochemical Cycles 16(4):1135. doi:10.1029/2001GB001823, 2002.

13. W.T. Baisden, R. Amundson, A.C. Cook, and D.L. Brenner. 2002. Turnover and storage of C and N in five density fractions from California annual grassland surface soils. Global Biogeochemical Cycles 16(4):1117, doi 10.1029/20001GB001822, 2002.

14. Sharp, W.D., K.L. Ludwig, O.A. Chadwick, R. Amundson, and L. Glaser. 2003.Datin fluvial terraces by 230Th/U on pedogenic carbonate. Wind River Basin, Wyoming . Quaternary Research 59:139-150.

15. Baisden, W.T. and R. Amundson. 2003. An analytical approach to ecosystem biogeochemistry modeling. Ecological Applications 13(3):649-663.

16. Sanderman, J., R. Amundson, and D. D. Baldocchi. 2002. Application of eddy covariance measurements to the temperature dependence of soil organic matter mean residence time. Global Biogeochemical Cycles 17(2):1061, soi:10.1029/2001GB1833,2003.

17. Amundson, R., Y. Guo, and P. Gong. 2003. Soil diversity and land use in the United States.Ecosystems 6:470-482.

18. Guo, Y., R. Amundson, P. Gong, and R. Ahrens. 2003. Taxonomic structure, distribution, and abuance of the soils in the USA. Soil Science Society of America Journal 67:1507-1516.

19. Y. Guo, P. Gong, and R. Amundson. 2003. Pedodiversity in the United States of America. Geoderma 117:99-115.

20. Amundson, R., A.T. Austin, E.A.G. Schuur, V. Matzek, A. Uebersax, D. Brenner, W.T. Baisden, and C. Kendall. 2002. Global patterns of the isotopic composition of soil and plant nitrogen. Global Biogeochemical Cycles 17(1):1031, doi:10.1029/2002GB001903, 2003.

21. Osher, L.J., P.A. Matson, and R. Amundson. 2003. Effect of land use change on soil carbon in Hawaii. Biogeochemistry 65(2):213-232.

22. Miller, A.J., R. Amundson, I.C. Burke, and C. Yonker. 2004. The effect of climate and cultivation on soil organic C and N. Biogeochemistry67(1):57-72.

23. Hoppe, K.A., R. Amundson, M. Vavra, M.P. McClaren, and D.L. Anderson. 2004. Isotopic analysis of tooth enamel carbonate from modern North American feral horses: implications for paleoenvironmental reconstructions. Palaeogeography, Palaeoclimatology, and Palaeoecology. 203(3-4):299-311.

Book Chapters etc.

1. Hoosbeek, M.R., R.G. Amundson, and R.B. Bryant. 1999. Pedological modeling. Chapter 3. In: (L.P. Wilding, Associate Editor) Handbook of Soil Science; Section V. Pedology. CRP Press. (in press).

2. Amundson, R. 2000. Are soils endangered? p, 144-153. In: (J. Schneiderman, ed) The Earth Around Us. W.H. Freeman and Co.

3. Amundson, R. 2000. Are soils endangered? California Geology July/Aug:4-13 (illustrated reprint of citation above).

4. Amundson, R. and W.T. Baisden. 2000. Stable isotope tracers and models in soil organic matter studies. pp. 117-137 In: O. Sala, H. Mooney, B. Howarth, and R.B. Jackson (eds), Methods in Ecosystem Science. Springer Verlag.

5. Mermut, A.R., R. Amundson, and T. Cerling. 2000. The use of stable isotopes in studying carbonate dynamics in soils. p. 65-86 In: R. Lal, J.M. Kimble, H. Eswaren, and B.A. Stewart (eds), Global Climate Change and Pedogenic Carbonates. Lewis Publishers, Washington, DC.

6. Amundson, R. 2002. Pedological Modeling. In: R. Lal (ed). Encyclopedia of Soil Science.

7. McFadden, L. and R. Amundson. 2002. Soil inorganic carbon modeling. In: R. Lal (ed). Encyclopedia of Soil Science.

8. Amundson, R. 2002. Donath Medal citation for Hope Jahren. GSA Today. 12(2):17-18.

9. Amundson, R. 2004. Soil Formation. Chap. 5.01, pp. 1-35. In: Treatise on Geochemistry, H.D. Holland and K.K. Turekian (Eds in Chief). Elsevier Press, Amsterdam.

10. Sanderman, J. and R. Amundson. 2004. Biogeochemistry of decomposition and detrital processing. Chap. 8.07, pp. 249-316. In: Treatise on Geochemistry, H.D. Holland and K.K. Turekian (Eds in Chief). Elsevier Press, Amsterdam.