Microbial activity and litter decomposition under snow cover in a cool-temperate broad-leaved deciduous forest
Microbial activity and litter decomposition under snow cover in a cool-temperate broad-leaved deciduous forest
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DOI：
10.1016/j.agrformet.2005.11.003
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发表时间：
2005-11
影响因子：
6.2
通讯作者：
M. Uchida;W. Mo;T. Nakatsubo;Y. Tsuchiya;T. Horikoshi;H. Koizumi
中科院分区：
文献类型：
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作者：
M. Uchida;W. Mo;T. Nakatsubo;Y. Tsuchiya;T. Horikoshi;H. Koizumi
冬季土壤和积雪覆盖表面的CO2排放量可以代表冷温带阔叶落叶林年度碳循环的一个重要部分。然而，这种二氧化碳生产的来源知之甚少。为了阐明腐解微生物在冬季（12月至4月）碳循环中的作用，研究了日本冷温带阔叶落叶林凋落物层中有机基质（落叶和纤维素片）的质量损失率、微生物活性和真菌生物量。叶片质量损失率达13%，占全年质量损失的26%。在实验室中测量的落叶中的微生物呼吸，即使在-2 °C也能检测到。麦角甾醇含量（真菌生物量的指标）的纤维素片显着增加，在积雪覆盖的季节。从雪下落叶层中分离得到7个真菌属，包括油枝变孢菌、紫附球菌和腐殖酸菌。根据凋落物量、微生物呼吸的温度依赖性和凋落物层温度之间的关系，估算了冬季的微生物呼吸。凋落物层中的微生物排放了31 gCO 2-Cm−2，占冬季总CO2排放量的38%。这些结果表明，通过土壤呼吸，凋落物层中的微生物在冬季的碳循环中发挥了重要作用。
Winter CO2emissions from soil and snow-covered surfaces can represent a significant fraction of the annual carbon cycle in cool-temperate broad-leaved deciduous forests. The sources of this CO2production are, however, poorly understood. To clarify the role of saprophytic microorganisms in the carbon cycle during the winter (December–April), mass loss rates of organic substrates (leaf litter and cellulose sheets), and microbial activity and fungal biomass in the litter layer of a cool-temperate broad-leaved deciduous forest in Japan were investigated. The mass loss rate of leaves reached 13%, which accounted for 26% of the annual mass loss. Microbial respiration in the leaf litter, measured in the laboratory, was detected even at −2°C. The ergosterol content (an indicator of fungal biomass) of the cellulose sheets increased significantly in the snow-covered season. Seven genera of fungi including Varicosporium elodeae, Epicoccum purpurascens and Cylindrocarpon destructans were isolated from leaf litter collected from under snow cover. Microbial respiration during the winter was estimated based on the relationships between the amount of leaf litter available, the temperature dependency of microbial respiration and the temperature in the litter layer. The microorganisms in the litter layer emitted 31gCO2-Cm−2, which accounts for 38% of the total CO2efflux during the winter. These results suggest that through soil respiration, microorganisms in the litter layer play an important role in the carbon cycle during the winter.