川西亚高山-高山土壤表层有机碳及活性组分沿海拔梯度的变化

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 川西亚高山-高山土壤表层有机碳及活性组分沿海拔梯度的变化 DOI: 10.5846/stxb201304040605 作者: 作者单位: 成都大学城乡建设学院环境工程系,四川大学环境科学与工程系,四川大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(41271094, 40871124);中央高校基本科研业务费(2010SCU22007)资助项目 Changes of organic carbon and its labile fractions in topsoil with altitude in subalpine-alpine area of southwestern China Author: Affiliation: Department of Environmental Engineering, College of Urban and Rural Construction,Department of Environmental Science and Engineering,Sichuan University,Department of Environmental Science and Engineering,Sichuan University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:青藏高原东缘亚高山-高山地带土壤碳被认为是我国重要的土壤碳库,作为高海拔低温生态系统,土壤碳对土壤暖化的响应可能也更加敏感。该区域亚高山森林一般分布在海拔3200 m以上,上缘接高山树线和灌丛草地,土壤有机碳含量高。海拔梯度上变化的土壤环境因子是主要土壤温度,海拔梯度上高寒土壤有机碳及活性有机碳组的分布格局,可体现海拔梯度上温度因子对土壤碳动态的影响。对沿海拔3200 m(亚高山针叶林)、3340 m(亚高山针叶林)、3540 m(亚高山针叶林)、3670 m(亚高山针叶林)、3740 m(亚高山针叶林)、3850 m(高山林线)、3940 m(高山树线)、4120 m(高山草地)的土壤表层(0-20 cm)有机碳和活性有机碳组分含量进行分析,结果表明在该海拔范围内,表层土壤总有机碳含量随着海拔的升高而增加,显示高海拔有利于土壤碳的固存;土壤活性有机碳组分中,颗粒态有机碳含量及其占总有机碳比例与海拔呈显著正相关,在海拔最高的4120 m含量和占有机碳总量比例分别达到50.81 g/kg和56.52%。在该海拔范围内海拔越高颗粒态有机碳占有机碳比例越高,显示高海拔土壤有机碳更多以土壤颗粒态碳形式贮存。微生物量碳、水溶性碳、轻组分有机碳与海拔高度没有明显的相关性,表明这些活性有机碳组分受海拔因素影响不大;易氧化有机碳含量与海拔高度显著正相关。因此,颗粒态有机碳含量及其比例可作为高海拔地带土壤活性有机碳库动态的特征指标,表征高海拔地带土壤有机碳动态与贮量受温度影响的指标。 Abstract:The alpine-subalpine area of the eastern Tibetan Plateau, as typical high-altitude low-temperature ecosystem, is one of the most important soil carbon pools in China. The soil there has high content of organic carbon due to abundant biomass of the alpine forest and shrub land distributed in the area, and is considered to be more sensitive to soil warming than that in the tropic or subtropical area. The spatial distribution pattern of soil carbon and its labile fractions with altitude could reflect the combined effects of altitudinal biological and environmental factors, particularly the temperature, on soil carbon dynamics. In this study, total organic carbon and its labile fractions including particulate organic carbon, microbial biomass carbon, light fraction of organic carbon, easily oxidized organic carbon, and water soluble organic carbon in topsoil (0-20 cm) were determined with an aim to understand changes of their characteristics with elvational gradients. The investigated altitude range was from 3200 to 4120 m that was covered by subalpine coniferous forest at 3200, 3340, 3540, 3670 and 3740 m, timberline at 3850 m, alpine tree line at 3940 m, and alpine meadows at 4120 m. The results showed that content of total organic carbon in topsoil increased significantly with altitude in the studied range, indicating that high altitude and low temperature are conducive to carbon sequestration in soil. Content of particulate organic carbon content and its ratio to total organic carbon showed significantly positive correlations with altitude, with its concentration reaching up to 50.81 g/kg and and accounting for 56.52% of total organic carbon, as measured at the highest elevation of 4120 m. Therefore, particulate organic carbon had become the major component of total organic carbon with its ratio gradually increased with altitude. On the other hand, microbial biomass carbon, water-soluble carbon, light fraction of organic carbon, as the group of less affected labile fractions, did not change significantly within the studied altitude range, while the fraction of easily-oxidized organic carbon tended to increase with altitude. To sum up, concentrations of particulate and easily-oxidized organic carbon fractions in topsoil could be used as indicators of labile organic carbon dynamics and balance in subalpine-alpine area at different altitudes. Moreover, soil warming may exacerbate the mineralization of particulate organic carbon, resulting in the decrease of the proportion of total organic carbon in soil. The elevational gradient study offered useful insights into the dynamics of high-altitude soil carbon and the differentiation of its labile fractions. It is indicated that soil carbon pool at high altitude could become a new carbon source under future warming scenarios. 参考文献 相似文献 引证文献