Sequestration and turnover of plant‐ and microbially derived sugars in a temperate grassland soil during 7 years exposed to elevated atmospheric pCO2
Sequestration and turnover of plant‐ and microbially derived sugars in a temperate grassland soil during 7 years exposed to elevated atmospheric pCO2
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DOI：
10.1111/j.1365-2486.2006.01303.x
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发表时间：
2007-02
影响因子：
11.6
通讯作者：
M. Bock;B. Glaser;N. Millar
中科院分区：
文献类型：
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作者：
M. Bock;B. Glaser;N. Millar
温带草原对全球陆地碳(C)预算的贡献约为20%，其中糖类对土壤碳库的贡献为10%-50%。观测到的大气二氧化碳浓度(PCO2)的增加是否导致这些生态系统中额外的碳固存或土壤有机质(SOM)的矿化仍不清楚。因此，本研究的目的是研究大气二氧化碳浓度升高对土壤中植物糖(阿拉伯糖和木糖)和微生物衍生糖(岩藻糖、鼠李糖、半乳糖、甘露糖)的C固定和周转的影响。这项研究是在苏黎世附近的瑞士自由空气二氧化碳浓缩(Face)实验中进行的。连续7年，多年生黑麦草被暴露在环境和高二氧化碳(分别为36和60帕)中。与周围地块相比，Face地块中额外的二氧化碳在13C中被耗尽，因此可以通过化合物特有的稳定同位素分析(13C：12C)来确定新的(7年)C输入。样品被分成粘土、粉砂、细砂和粗砂，形成了相对稳定和不稳定的有机质储量，但周转率不同。与对照样地相比，暴露在高二氧化碳浓度下7年后，土壤中糖的总固着量约为28%。在环境样地和高地样地中，颗粒级分中的总糖浓度按沙子顺序增加。
Temperate grasslands contribute about 20% to the global terrestrial carbon (C) budget with sugars contributing 10–50% to this soil C pool. Whether the observed increase of the atmospheric CO2 concentration (pCO2) leads to additional C sequestration into these ecosystems or enhanced mineralization of soil organic matter (SOM) is still unclear. Therefore, the aim of the presented study was to investigate the impact of elevated atmospheric pCO2 on C sequestration and turnover of plant‐ (arabinose and xylose) and microbially derived (fucose, rhamnose, galactose, mannose) sugars in soil, representing a labile SOM pool. The study was carried out at the Swiss Free Air Carbon Dioxide Enrichment (FACE) experiment near Zurich. For 7 years, Lolium perenne swards were exposed to ambient and elevated pCO2 (36 and 60 Pa, respectively). The additional CO2 in the FACE plots was depleted in 13C compared with ambient plots, so that ‘new’ (<7 years) C inputs could be determined by means of compound‐specific stable isotope analysis (13C : 12C). Samples were fractionated into clay, silt, fine sand and coarse sand, which yielded relatively stable and labile SOM pools with different turnover rates. Total sugar sequestration into bulk soil after 7 years of exposure to elevated pCO2 was about 28% compared with the control plots. In both ambient and elevated plots, total sugar concentrations in particle size fractions increased in the order sand