Short-term dynamics of abiotic and biotic soil 13CO2 effluxes after in situ 13CO2 pulse labelling of a boreal pine forest.
Short-term dynamics of abiotic and biotic soil 13CO2 effluxes after in situ 13CO2 pulse labelling of a boreal pine forest.
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DOI：
10.1111/j.1469-8137.2009.02883.x
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发表时间：
2009-04
期刊：
影响因子：
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通讯作者：
J. Subke;H. Vallack;T. Magnusson;S. G. Keel;D. Metcalfe;P. Högberg;P. Ineson
中科院分区：
文献类型：
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作者：
J. Subke;H. Vallack;T. Magnusson;S. G. Keel;D. Metcalfe;P. Högberg;P. Ineson
物理扩散的同位素示踪剂进出土壤孔隙造成相当大的不确定性的时间和幅度的植物地下分配脉冲标记实验。在这里，我们划分土壤CO（2）同位素通量为非生物示踪剂通量（物理回报），异养通量，和自养通量贡献（13）CO（2）标记的瑞典樟子松森林。利用现场部署的质谱仪监测了土壤CO2排放及其同位素组成。此外，监测了土壤剖面中的（13）CO（2）。脉冲标记后48 h内，土壤孔隙中13 CO 2的物理（非生物）流出量显著，相当于6 d内生物标记通量的量。测量和模拟的变化（13）CO（2）浓度在整个土壤剖面证实了这些结果。示踪剂返回通过土壤CO（2）流出显着相关的衣领接近树木，而每天的总通量（包括异养和自养源）的幅度显示出令人惊讶的时间变化相比，异养通量。结果首次显示了物理同位素CO（2）示踪剂从土壤基质返回的混淆影响的意义，呼吁在未来的脉冲追踪实验中包括有意义的控制处理。
Physical diffusion of isotopic tracers into and out of soil pores causes considerable uncertainty for the timing and magnitude of plant belowground allocation in pulse-labelling experiments. Here, we partitioned soil CO(2) isotopic fluxes into abiotic tracer flux (physical return), heterotrophic flux, and autotrophic flux contributions following (13)CO(2) labelling of a Swedish Pinus sylvestris forest. Soil CO(2) efflux and its isotopic composition from a combination of deep and surface soil collars was monitored using a field-deployed mass spectrometer. Additionally, (13)CO(2) within the soil profile was monitored. Physical (abiotic) efflux of (13)CO(2) from soil pore spaces was found to be significant for up to 48 h after pulse labelling, and equalled the amount of biotic label flux over 6 d. Measured and modelled changes in (13)CO(2) concentration throughout the soil profile corroborated these results. Tracer return via soil CO(2) efflux correlated significantly with the proximity of collars to trees, while daily amplitudes of total flux (including heterotrophic and autotrophic sources) showed surprising time shifts compared with heterotrophic fluxes. The results show for the first time the significance of the confounding influence of physical isotopic CO(2)-tracer return from the soil matrix, calling for the inclusion of meaningful control treatments in future pulse-chase experiments.