안정성동위원소 기술을 이용한 토양의 유기물 보유에 대한 대기 CO2 및 온도 상승의 효과 해석 = Interpreting the Effect of Elevated CO2 and Temperature on Retention of Organic Carbon in Soil Using Isotope Technique

다국어 초록 (Multilingual Abstract)

The role of soil organic matter in attenuating or accelerating climate change is one of the major concerns. Decomposition of soil organic matter can influence the global carbon balance due to possible feedback by warming to greenhouse gas emissions and climate change. To predict the effect of global warming and elevated-air CO2 on soil organic matter, we studied the variation in contents and isotope composition with soil depth under elevated CO2 (ambient + 300 ppmv) and temperature (ambient + 5°C). The carbon isotope compositions (δ13C) under elevated CO2 condition were apparently higher than those under ambient CO2 condition, indicating that carbon isotope composition under elevated CO2 condition can be a possible integrator to trace carbon dynamics in soils. The higher carbon contents and the lower δ13C values in soils under elevated CO2 compared with ambient condition indicated that the influx of organic matter into soil was increased and its retention was also increased. However, soil organic matter decomposed fast under elevated temperature condition compared with ambient condition, which was reflected by the 13C enrichment with elevating temperature. Our results suggested that elevated CO2 and temperature would increase the influx of organic matter into soils but the organic matter would decompose faster with elevating temperature and that the carbon isotope signature of soil could be used as a reliable tool to interpret carbon dynamics in soils.