QQ客服 官方微博 反馈留言

题名	大兴安岭冻土湿地泥炭有机碳矿化对气候变化因子的潜在响应
作者	王宪伟
答辩日期	2006-06-01
文献子类	博士
授予单位	中国科学院沈阳应用生态研究所
授予地点	沈阳应用生态研究所
关键词	气候变化 土壤有机质矿化 冻土湿地 培养实验 模型
其他题名	Potential Effect of Climate change on Soil Organic Carbon Mineralization of Permafrost wetlands in the Great Hing’an Mountains, Northeastern China
英文摘要	Northern Great Hing’an Mountains are the main areas of China’s permafrost and permafrost wetlands. In the past 30 years, Great Hing’an Mountains faced significant warming. Human activities also intensified. The permafrost was severely degraded. Original wetland shrinkage and new wetland emergence occurred in the mean time. Now, permafrost wetland research is still very limited in the Great Hing’an Mountains. Most of the earlier studies were qualitative and little was quantitative, focusing on the distribution of permafrost wetland, the mechanism between permafrost and wetland, and description of permafrost degradation and its impact on wetlands. We measured the peat carbon mineralization under different soil temperatures and soil moistures and under freezing-thawing treatment cycles through the incubation experiment, with samples collected from the permafrost wetlands in the Great Hing’an Mountains. Combined with regression models, we analyzed the effects of soil temperature and soil moisture on peat carbon mineralization and discussed the response of permafrost wetland to climate change under linear climate scenarios. The main conclusions obtained are as follows: (1) There is a discontinuous carbon pool in the peat layer of the permafrost wetlands in the Great Hing’an Mountains. The depths of peat layer are different because of the topographical conditions, the active layers and climatic factors. The contents of organic carbon and total nitrogen were very high. There was a decreasing trend of peat carbon with depth, but the trend of total nitrogen with depth was not consistent. The contents of the total nitrogen are influenced by climatic conditions, micro-topography and vegetation types. The peat C/N ratios in the continuous permafrost zone were higher than that in the discontinuous permafrost zone. There was a significant coupled relationship between contents of peat carbon and total nitrogen. (2) The peat carbon mineralization of permafrost wetlands increased with the temperature in the Great Hing’an Mountains. The total carbon mineralization of peat carbon ranged between 18.55 to 112.91 mg g-1, when the temperature ranged between 5 and 20℃. Although the contents of peat carbon and total nitrogen in the continuous permafrost zone were higher than those in the discontinuous permafrost zone, the peat carbon mineralization was significantly affected by the temperature in the discontinuous permafrost zone, because the temperature sensitivity Q10 values were higher in the discontinuous permafrost zone. Through the analysis of a kinetics function, the response of the peat carbon mineralization was more significant to 15 ℃ than that under other temperatures in the permafrost wetlands of the Great Hing’an Mountains. (3) The peat carbon mineralization was obviously affected by the soil moisture in the permafrost wetlands of the Great Hing’an Mountains. The total carbon mineralization increased with soil moisture till the optimal level, and then decreased. The optimal soil moisture was 60%WHC according to the experiment treatments. A quadric regression model successfully predicted carbon mineralization as a function of soil moisture. The optimal soil moisture was 63%WHC for 10-20cm peat layer and 65%WHC for 20-30cm peat layer, respectively in the permafrost wetlands of the Great Hing’an Mountains, according to the prediction of the model. The optimal soil moisture was 65%WHC for 10-20cm peat layer and 59% for 20-30cm peat layer respectively in the discontinuous permafrost wetlands. (4) Total carbon mineralization was significantly affected by temperature and soil moisture in the permafrost wetlands of the Great Hing’an Mountains. The total carbon mineralization rate in the continuous permafrost zone was higher than that in the discontinuous permafrost zone, because the contents of peat organic carbon and total nitrogen were higher in the continuous permafrost zone. A two-compartment model based on temperature and moisture successfully fit the dynamics of peat carbon mineralization (P<0.001). Through analysis of the regression function and ANOVA, we found that soil temperature and soil moisture were equally important in the peat carbon mineralization process of the permafrost wetland in the Great Hing’an Mountains. (5) The peat carbon mineralization of the permafrost wetlands was not significantly affected by the freezing-thawing process in the Great Hing’an Mountains. The study area belongs to the cold-temperature zone. The frequency of freezing-thawing cycle would increase under climate warming. The effects of freezing-thawing on peat mineralization of permafrost wetlands in the Great Hing’an Mountains should be considered as an additional factor in the long run. (6) The main annual temperature had increased significantly and annual precipitation had not been stable according to the analysis of the data from weather stations in the Great Hing’an Mountains. Both original wetland shrinkage and expansion of new wetland occurred due to permafrost degradation. The oligotrophic bog would be successed by eutrophic swamp or marsh in the discontinuous permafrost zone. The wetlands succession would become complicated and there would be more types in the continuous permafrost zone. We used linear regression model to predict the climate change. The results showed the carbon mineralization of permafrost wetlands would be significantly affected by the climate change in the Great Hing’an Mountains, especially under the wetter condition. A large proportion of permafrost wetlands are potentially mineralized and it would lead to a positive feedback effect under climate change.; 大兴安岭地区是我国地带性多年冻土和冻土湿地的主要分布区，近30年来，大兴安岭地区整体增温显著，气候变化的幅度加大，加之人类活动的频繁，冻土退化严重，冻土湿地出现了原有湿地萎缩和新生湿地扩张的现象。目前，对大兴安岭多年冻土湿地的研究还非常有限，且定性的研究较多，定量的研究极少，多数研究集中于冻土湿地的分布，冻土与湿地之间的机理探讨及描述多年冻土退化对湿地产生的影响等方面。 本论文通过室内培养实验，分析不同温度和湿度梯度及冻融作用下，大兴安岭不同多年冻土区湿地两层泥炭有机碳的矿化状况。结合回归模型，分析大兴安岭多年冻土湿地泥炭有机碳矿化对不同温度和湿度的响应，探讨在气候预案下，大兴安岭多年冻土湿地对气候变化的潜在响应。获得的主要结论如下： （1）大兴安岭多年冻土湿地存在着碳储层，其不同的冻土湿地区由于自然条件、融深等因素的不同，碳储层的厚度也存在着差异。多年冻土湿地含碳量和含氮量都很高，有机碳含量随剖面深度的增加有降低的趋势，泥炭全氮的含量随剖面深度变化复杂，这与湿地土壤形成的气候条件、微地貌和植被类型等有关。大兴安岭连续多年冻土区泥炭，C/N比要高于不连续多年冻土区湿地，并且有机碳含量与全氮含量存在着很好的耦合关系。 （2）大兴安岭多年冻土湿地泥炭有机碳矿化随温度的升高而升高，在培养温度5-20℃下，总的泥炭有机碳矿化量变化范围为18.55~112.91 mg g-1。虽然连续多年冻土区湿地泥炭有机碳矿化率和矿化量都要高于不连续多年冻土区湿地，但经过温度敏感性系数Q10分析，大兴安岭不连续多年冻土区湿地泥炭矿化对温度的响应更显著。从一元动力学方程分析结果来看，大兴安岭多年冻土湿地泥炭有机碳的矿化对15℃响应更显著。 （3）土壤湿度对大兴安岭多年冻土湿地泥炭有机碳矿化产生一定的影响，泥炭总矿化量出现了先随湿度的增加而增加，达到最适宜值后降低的趋势。从本论文的实验设置来看，大兴安岭多年冻土湿地泥炭有机碳矿化的最适宜湿度为60%WHC。利用二元回归模型很好地反映了湿度对大兴安岭多年冻土湿地泥炭矿化的影响，模型推测大兴安岭连续多年冻土区湿地泥炭有机碳矿化的最优湿度为10-20cm层63%WHC，20-30cm层65%WHC；不连续多年冻土区湿地有机碳矿化的最优湿度为10-20cm层65%WHC，20-30cm层59%WHC。 （4）大兴安岭多年冻土湿地泥炭有机碳矿化受温度和湿度的影响显著，其之间的交互作用同样显著。连续多年冻土区湿地有机碳矿化量要高于不连续多年冻土区湿地，这与其含有更高的有机碳和全氮有关。温度和湿度对泥炭有机碳矿化的影响可以用二元二次回归方程很好的表示（P<0.001），通过回归方程和方差分析，结果表明温度和湿度对大兴安岭多年冻土湿地泥炭有机碳矿化都非常重要。 （5）通过培养实验结果显示，虽然温度仍是影响大兴安岭多年冻土湿地泥炭有机碳矿化的主要因子，但随冻融作用处理次数的增加，冻土湿地泥炭有机碳矿化量和温度敏感性系数Q10值有增加的趋势，这意味着冻融作用对大兴安岭多年冻土湿地泥炭矿化产生了不小的影响。虽然冻融作用对大兴安岭多年冻土湿地的影响并不是很大，但大兴安岭处于寒温带，在气候变暖下，冻融过程的频率将加高，冻融作用对大兴安岭多年冻土湿地的影响不容忽视。 （6）大兴安岭地区近30年气候变化趋势分析表明，年均温增长显著，年降水量变化幅度大。在气候变化下，对于不连续多年冻土区，多年冻土不断的退缩及最终的消失，会使冻土湿地萎缩和消失，原有的典型的贫营养的泥炭藓沼泽湿地可能演化为富营养的苔草沼泽湿地或灌丛沼泽湿地，对于大片连续多年冻土区，冻土湿地的变化更加复杂，出现的湿地类型会更多。通过线性气候预案下的大兴安岭多年冻土湿地泥炭有机碳矿化分析，结果显示大兴安岭多年冻土湿地对气候变化响应显著，特别是对于变湿的环境。气候变化下，大兴安岭多年冻土湿地泥炭存在着潜在的分解，多年冻土湿地与气候变化之间存在着正反馈机制。 目前研究表明，大兴安岭地区对气候变化特别敏感，对大兴安岭冻土湿地的研究既填补了国内研究的空白，又对全球的碳循环研究提供了数据支持，并且加深了对冻土湿地生态过程的了解。
语种	中文
公开日期	2010-12-15
页码	152
内容类型	学位论文
源URL	[http://210.72.129.5/handle/321005/2767]
专题	沈阳应用生态研究所_沈阳应用生态研究所
推荐引用方式 GB/T 7714	王宪伟. 大兴安岭冻土湿地泥炭有机碳矿化对气候变化因子的潜在响应[D]. 沈阳应用生态研究所. 中国科学院沈阳应用生态研究所. 2006.

个性服务

查看访问统计

相关权益政策

暂无数据

收藏/分享

除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。