Estimation of ¹⁴CO₂ flux at soil-atmosphere interface and distribution of ¹⁴C in forest ecosystem

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• 作者：Koarashi ; Jun ; Amano ; Hikaru ; Andoh ; Mariko ; Iida ; Takao ; Moriizumi ; Jun
• 关键词：¹⁴C ; ¹⁴CO₂ flux ; Flow-through chamber method ; Forest ecosystem
• 刊名：Journal of Environmental Radioactivity
• 出版年：2002
• 出版时间：2002
• 年：2002
• 卷：60
• 期：3
• 页码：249-261
• 全文大小：215 K

文摘

To realize the dynamical behavior of ¹⁴C among exchangeable carbon reservoirs in terrestrial environment, a method for in situ determination of ¹⁴CO₂ flux at soil-atmosphere interface and a high flow rate CO₂ sampler were developed. This method allowed us to collect integrated quantity of CO₂ for determining ¹⁴C activity over an extended time period under environmental conditions with minimal site disturbance. The ¹⁴CO₂ flux from ground surface was estimated to be 1.59×10⁻⁵Bqm⁻²s⁻¹ in a forest floor with the method. The specific activities of ¹⁴C in environmental materials such as some biological and air samples were also determined in the vicinity of the place, where the flux measurement was made, to discuss the behavior of ¹⁴C in the forest ecosystem. The results indicated that fresh pine needles had a similar ¹⁴C specific activity to the atmospheric CO₂ at the same height due to its fairly rapid equilibrium, ¹⁴C specific activity in the atmospheric CO₂ has a concentration gradient near the ground surface and, at least in this site, CO₂ with high ¹⁴C specific activity was generated by decomposition of soil organic matter which may be accumulated in soil as a result of former nuclear weapons tests.