Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-15T04:17:14.668Z Has data issue: false hasContentIssue false
  • English
  • Français

Using 14C as a Tracer of Carbon Accumulation and Turnover in Soils

Published online by Cambridge University Press:  18 July 2016

G. M. Milton  and
S. J. Kramer
G. M. Milton
Affiliation:
Environmental Research Branch, AECL Chalk River Laboratories, Chalk River Ontario, Canada, K0J 1J0
S. J. Kramer
Affiliation:
Environmental Research Branch, AECL Chalk River Laboratories, Chalk River Ontario, Canada, K0J 1J0
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Three very different Canadian soils—clay soils of the St. Lawrence Lowlands, sandy forest soils of the Ottawa Valley, and organic-rich sediments from a wetland on the Canadian Shield—have been cored, sliced and separated into different density fractions, and the radiocarbon content of these soil fractions measured. In two of the areas sampled, cores were obtained close to operating nuclear reactors, as well as from beyond their region of influence. As a consequence, it has been possible to ascertain the depths of penetration of both the weapons-testing pulse (peaking in 1963), and a 25–50-yr chronic reactor input of 14C.

The percentage of carbon stored in different density fractions varied with soil type. Turnover times for bulk soil organic carbon, estimated from soil degassing rates, have been compared with those predicated on the residual “bomb” 14C in background cores, and/or on the ratio of reactor-emitted 14C retained in the soils to the total deposited during the lifetime of operation. Residence times for the heavy carbon fraction present at depths below the influence of anthropogenic inputs have also been estimated.

The accumulated data will be incorporated in a revised soil model, adjusted for the parameters deemed to be most important to carbon turnover rates under Canadian conditions.

Type
Part 2: Applications
Information
Radiocarbon , Volume 40 , Issue 2: 16th International Radiocarbon Conference June 16-20, 1997 Part 2: Applications, Conference Editors: Willem G. Mook Johannes van der Plicht , 1997 , pp. 999 - 1011
Copyright
Copyright © The American Journal of Science 

References

Alexandrovskiy, A. L. and Chichagova, O. A. 1998 The 14C Age of Humic Substances in Paleosols. Radiocarbon , this issue.CrossRefGoogle Scholar
Cherkinsky, A. E. 1996 14C dating and soil organic matter dynamics in Arctic and Subarctic ecosystems. Radiocarbon 38(2): 241–245.Google Scholar
Harrison, K. G. 1996 Using bulk soil measurements to estimate soil organic matter turnover times: Implications for atmospheric CO2 levels. Radiocarbon 38(2): 181–190.Google Scholar
Kurz, W. A., Apps, M. J., Webb, T. M. and McNamee, P. J. 1992 The carbon budget of the Canadian forest sector: Phase I. Forestry Canada , Information Report NOR-X-326.Google Scholar
Leavitt, S. W., Follett, R. F. and Paul, E. A. 1996 Estimation of slow- and fast-cycling soil organic carbon pools from 6N HCl hydrolysis. Radiocarbon 38(2): 231–239.CrossRefGoogle Scholar
Milton, G. M., Kramer, S. J., Brown, R. M., Repta, C. J. W., King, K. J. and Rao, R. R. 1995 Radiocarbon dispersion around Canadian nuclear facilities. In Cook, G. T., Harkness, D. D., Miller, B. F. and Scott, E. M., eds., Proceedings of the 15th International 14C Conference. Radiocarbon 37(2): 485–496.Google Scholar
Plewinsky, B. and Kamps, R. 1984 Sodium metatung-state, a new medium for binary and ternary density gradient centrifugation. Macromolecular Chemistry 185: 1429–1439.CrossRefGoogle Scholar
Raich, J. W. and Schlesinger, W. H. 1992 The global carbon dioxide flux in soil respiration and its relationship to vegetation and climate. Tellus (44B): 81–99.Google Scholar
Robertson, W. D. and Cherry, J. A. 1989 Tritium as an indicator of recharge and dispersion in a groundwater system in central Ontario. Water Resources Research 25(6): 1097–1109.CrossRefGoogle Scholar
Ryan, M. C., Aravena, R. and Gilham, R. W. 1995 The use of 13C natural abundance to investigate the turnover of the microbial biomass and active fractions of soil organic matter under two tillage treatments. In Lal, R., Kimble, J., Levine, E. and Stewart, B. A., eds., Soils and Global Change. London, Lewis Publishers: 351–360.Google Scholar
Trumbore, S. E. 1993 Comparison of carbon dynamics in tropical and temperate soils using radiocarbon measurements. Global Biogeochemical Cycles 7(2): 275–290.Google Scholar
Trumbore, S. E., Chadwick, O. A. and Amundson, R. 1996 Rapid exchange of soil carbon and atmospheric CO2 driven by temperature change. Science 272: 393–396.Google Scholar
Whittaker, R. H. and Likens, G. E. 1973 Carbon in biota. In Woodell, G. M. and Pecan, E. V., eds., Carbon and the Biosphere. U.S. Atomic Energy Commission CONF-720510.Google Scholar