Sun Jian Fei, Dai Wei Wei, He Tong Xin, Peng Bo, Jiang Ping, Han Shi Jie, Bai E
Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Guangxi Teachers Education University, Nanning 530001, China.
Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Aca-demy of Sciences, Shenyang 110016, China.
Ying Yong Sheng Tai Xue Bao. 2017 Jul 18;28(7):2179-2185. doi: 10.13287/j.1001-9332.201707.039.
The rising atmospheric CO concentration significantly changed soil nitrogen (N) cycling which is important for us to predict the carbon (C) sequestration potential of terrestrial ecosystems. The natural abundance of N isotope as an integrative indicator of ecosystem N cycling processes can effectively indicate the effect of elevated CO on soil N cycling processes. Here, we used an open top chamber experiment to examine the effects of elevated COfor ten years on the natural abundance of Quercus mongolica, soil and microbial biomass C and N isotopes in northeastern China. Our results showed that elevated CO significantly changed soil N cycling processes, resulting in the increase of microbial and leaf δN; stimulated the decomposition of C-enriched soil organic C, and offset the effect of more C-depleted plant photosynthetic C inputs, resulting in unchanged δC of soil dissolved organic C and microbes under elevated CO. These results indicated that elevated CO likely increased the mineralization of soil organic matter, and the system is getting more N-limited.
大气中二氧化碳（CO）浓度的上升显著改变了土壤氮（N）循环，这对于我们预测陆地生态系统的碳（C）固存潜力至关重要。氮同位素的自然丰度作为生态系统氮循环过程的综合指标，能够有效指示二氧化碳浓度升高对土壤氮循环过程的影响。在此，我们利用开顶式气室实验，研究了二氧化碳浓度升高十年对中国东北蒙古栎的自然丰度、土壤以及微生物生物量碳和氮同位素的影响。我们的结果表明，二氧化碳浓度升高显著改变了土壤氮循环过程，导致微生物和叶片δN增加；刺激了富含碳的土壤有机碳的分解，并抵消了植物光合碳输入中更多贫碳的影响，导致二氧化碳浓度升高下土壤溶解有机碳和微生物的δC保持不变。这些结果表明，二氧化碳浓度升高可能增加了土壤有机质的矿化作用，并且该系统正变得更加受氮限制。
