• 关键词：泥炭  矿化速率  温度敏感性  碳排放  有机质性质  水解酶  泥炭地

• 基金项目：国家自然科学基金（No.41771497）

• 赵烨彤
• 东北师范大学，长白山地理过程与生态安全教育部重点实验室，长春 130024;东北师范大学泥炭沼泽研究所，长春 130024

• 汪祖丞
• 东北师范大学，长白山地理过程与生态安全教育部重点实验室，长春 130024;东北师范大学泥炭沼泽研究所，长春 130024

• 徐志伟
• 东北师范大学，长白山地理过程与生态安全教育部重点实验室，长春 130024;东北师范大学泥炭沼泽研究所，长春 130024

• 郭彤
• 东北师范大学，长白山地理过程与生态安全教育部重点实验室，长春 130024;东北师范大学泥炭沼泽研究所，长春 130024

• 摘要：北方泥炭地是全球重要的碳汇，也是全球变暖最为敏感的区域之一.然而，由于泥炭地表层和亚表层泥炭土碳排放过程对全球变暖的响应过程及机制仍存在一定争议，目前对全球变暖背景下泥炭地碳排放的认识仍存在一定不足.本研究于2019年8月在大兴安岭满归泥炭地采集表层（0~10 cm）和亚表层（15~30 cm）泥炭土进行室内增温模拟有氧培养，测定其矿化速率、有机质性质和水解酶活性.结果表明，表层泥炭土矿化速率在5、15、25 ℃下培养时（（142.8±66.9）~（545.3±30.6）、（575.0±62.1）~（1843.0±547.4） 、（888.4±123.9）~（3646.7±167.9） μg·g^-1·d^-1）均 高于亚表层（（113.0±41.5）~（367.1±64.1）、（357.4±52.3）~（1122.1±218.8）、（697.1±38.1）~（2336.4±150.6） μg·g^-1·d^-1），但表层和亚表层矿化作用的温度敏感性不具有显著差异；培养过程中，表层与亚表层泥炭土β-1，4-N-乙酰葡糖胺糖苷酶（NAG）活性存在显著差异，但β-1，4-葡萄糖苷酶（BG）和酸性磷酸酶（AP）活性相似；表层和亚表层泥炭土总有机碳（TOC）、总氮（TN）、碳氮比（C/N）及纤维素含量均存在显著差异.在具体有机质组成方面，亚表层泥炭土中芳香族的惰性有机质含量较多，而表层泥炭土中多糖类的活性有机质含量较高，且芳香族化合物与泥炭土矿化速率呈显著负相关.综上，本研究认为全球变暖对表层和亚表层泥炭土矿化作用的影响没有显著性差异，常见的NAG、BG和AP酶并不是引起亚表层泥炭土矿化速率较慢的原因，而亚表层泥炭土中含有更多的惰性有机质可能是导致亚表层泥炭土矿化速率较低的主要因素.

• Abstract：Northern peatlands are an important carbon sink in the world， and is also one of the most sensitive areas to global warming. However， given the debate on how the respiration of surface and subsurface peat soil response to global warming， how carbon emissions respond to global change in peatlands still remains unknown. In this study， the surface （0~10 cm） and subsurface （15~30 cm） peat soils were collected from the Mangui peatland in Great Xingan Mountain in August 2019 and incubated under aerobic environment at different temperatures in laboratory. The mineralization rates， organic matter properties and soil extracellular hydrolase were measured. Results showed that the mineralization rates of surface peat soil during incubation at 5 ℃， 15 ℃， 25 ℃（（142.8±66.9）~（545.3±30.6） μg·g^-1·d^-1， （575.0±62.1）~（1843.0±547.4） μg·g^-1·d^-1 and （888.4±123.9）~（3646.7±167.9） μg·g^-1·d^-1） were significantly higher than those of subsurface （（113.0±41.5）~（367.1±64.1） μg·g^-1·d^-1， （357.4±52.3）~（1122.1±218.8） μg·g^-1·d^-1 and （697.1±38.1）~（2336.4±150.6） μg·g^-1·d^-1）， though the difference in temperature sensitivity was not statistically significant. During the incubation， the β-1，4-N-acetylglucosaminidase （NAG） activity in surface was significantly higher than that in subsurface peat soil， but β-1，4-glucosidase （BG） and acid phosphatase （AP） activities between surface and subsurface peat soils were similar. Significant differences in TOC， TN， C/N and fiber content between surface and subsurface peat soils were observed. In terms of specific compositions of organic matters， the subsurface peat soil contained more aromatic compounds， while the surface peat soil had a higher content of polysaccharides. A significant negative correlation between aromatic compounds and peat soil mineralization rate was also observed. In summary， as global warming did not affect mineralization of surface and subsurface peat soils differently， this study suggests that inert organic matters in subsurface peat soil rather than NAG， BG， and AP enzymes are the major reason for the slower mineralization.

• Key words：peat  mineralization rate  temperature sensitivity  carbon emission  properties of organic matters  hydrolase  peatland

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