土壤水分
环境科学
土壤呼吸
土壤碳
生态系统
浸出(土壤学)
生长季节
矿化(土壤科学)
农学
土壤科学
生态学
生物
作者
Frank Hagedorn,Melissa R. Martin,Christian Rixen,Silvan Rusch,Peter Bebi,Alois Zürcher,Rolf Siegwolf,Sonja Wipf,Christophe Escape,Jacques Roy,Stephan Hättenschwiler
出处
期刊:Biogeochemistry
[Springer Nature]
日期:2009-04-01
卷期号:97 (1): 7-19
被引量:108
标识
DOI:10.1007/s10533-009-9297-9
摘要
Climatic warming will probably have particularly large impacts on carbon fluxes in high altitude and latitude ecosystems due to their great stocks of labile soil C and high temperature sensitivity. At the alpine treeline, we experimentally warmed undisturbed soils by 4 K for one growing season with heating cables at the soil surface and measured the response of net C uptake by plants, of soil respiration, and of leaching of dissolved organic carbon (DOC). Soil warming increased soil CO2 effluxes instantaneously and throughout the whole vegetation period (+45%; +120 g C m y−1). In contrast, DOC leaching showed a negligible response of a 5% increase (NS). Annual C uptake of new shoots was not significantly affected by elevated soil temperatures, with a 17, 12, and 14% increase for larch, pine, and dwarf shrubs, respectively, resulting in an overall increase in net C uptake by plants of 20–40 g C m−2y−1. The Q 10 of 3.0 measured for soil respiration did not change compared to a 3-year period before the warming treatment started, suggesting little impact of warming-induced lower soil moisture (−15% relative decrease) or increased soil C losses. The fraction of recent plant-derived C in soil respired CO2 from warmed soils was smaller than that from control soils (25 vs. 40% of total C respired), which implies that the warming-induced increase in soil CO2 efflux resulted mainly from mineralization of older SOM rather than from stimulated root respiration. In summary, one season of 4 K soil warming, representative of hot years, led to C losses from the studied alpine treeline ecosystem by increasing SOM decomposition more than C gains through plant growth.
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