Carbon cycling in terrestrial environments: Chapter 17
This chapter reviews a number of applications of isotopic techniques for the investigation of carbon cycling processes. Carbon dioxide (C02) is an important greenhouse gas. Its concentration in the atmosphere has increased from an estimated 270 ppm at the beginning of the industrial revolution to ∼ 360 ppm at present. Climatic conditions and atmospheric C02 concentration also influence isotopic discrimination during photosynthesis. Natural and anthropogenically induced variations in the carbon isotopic abundance can be exploited to investigate carbon transformations between pools on various time scales. It also discusses one of the isotopes of carbon, the 14C, that is produced in the atmosphere by interactions of cosmic-ray produced neutrons with stable isotopes of nitrogen (N), oxygen (O), and carbon (C), and has a natural abundance in the atmosphere of ∼1 atom 14 C per 1012 atoms 12C. The most important factor affecting the measured 14C ages of soil organic matter is the rate of organic carbon cycling in soils. Differences in the dynamics of soil carbon among different soils or soil horizons will result in different soil organic 14C signatures. As a result, the deviation of the measured 14C age from the true age could differ significantly among different soils or soil horizons.
|Carbon cycling in terrestrial environments: Chapter 17
|Yang Wang, Thomas G. Huntington, Laurie J. Osher, Leonard I Wassenaar, Susan E. Trumbore, Ronald Amundson, Jennifer W. Harden, Diane M. McKnight, Sherry L. Schiff, George R. Aiken, W. Berry Lyons, Ramon O. Aravena, Jill Baron
|USGS Publications Warehouse
|Fort Collins Science Center