Sensitivity of peatland carbon loss to organic matter quality
Sensitivity of peatland carbon loss to organic matter quality
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DOI：
10.1029/2012gl051856
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发表时间：
2012-07-24
影响因子：
5.2
通讯作者：
Galego-Sala, Angela
中科院分区：
文献类型：
--
作者：
Leifeld, Jens;Steffens, Markus;Galego-Sala, Angela
泥炭地土壤储存了大量的有机质（OM）。在泥炭形成过程中，容易分解的有机质优先损失，更多的有机质部分积累。因此，在泥炭剖面中，有机质质量随深度而变化。排水和持续的气候变化造成了有机质快速流失的风险，当以前缺氧的泥炭层氧化。在泥炭分解过程中，更深、更易分解的泥炭暴露在富氧表面，这可能会影响分解速率。我们发现，扰动温带泥炭地的土壤呼吸速率强烈控制泥炭的质量，特别是其多糖含量。通过固体C-13 NMR和DRIFT光谱推断了在更大范围的泥炭地网站与不同程度的干扰土壤剖面的多糖含量。这些数据证实了一个强烈的下降，多糖含量与深度和一个贫穷的OM质量的土壤排水几十年前的表面泥炭。我们结合呼吸和光谱测量的证据，推断泥炭地碳损失的敏感性相对于OM质量缩放测量质量的泥炭地沉降和碳损失的142年的记录在一个网站。根据质量与呼吸作用之间的函数关系，在该地点测得的平均年碳损失率为2.5 t C ha（-1），在泥炭地排水开始时为20 t C ha（-1），近年来下降到不到1 t C ha（-1）。引文：Leifeld，J.，M. Steffens和A. Galego-Sala（2012），泥炭地碳损失对有机质质量的敏感性，Geophys。保留信函：39，L14704，doi：10.1029/2012GL051856。
Peatland soils store substantial amounts of organic matter (OM). During peat formation, easily decomposable OM is preferentially lost and more recalcitrant moieties accumulate. In a peat profile, OM quality thus scales with depth. Drainage and ongoing climate change poses the risk of rapid OM loss when formerly anoxic peat layers oxidize. During peat decomposition, deeper, more recalcitrant peat is exposed to the oxygen-rich surface, which may influence the decomposition rate. We show that the soil respiration rate of a disturbed temperate peatland is strongly controlled by the peat's quality and especially its polysaccharides content. The polysaccharide content of soil profiles in a wider range of peatland sites with differing degrees of disturbance was inferred by means of solid-state C-13 NMR and DRIFT spectroscopy. The data confirmed a strong decline in polysaccharide content with depth and a poor OM quality of surface peat in soils drained decades ago. We combined the evidence from respiration and spectroscopic measurements to deduce the sensitivity of peatland carbon loss with respect to OM quality by scaling measured quality to a 142-years record of peatland subsidence and carbon loss at one of the sites. According to the functional relationship between quality and respiration, the measured average annual carbon loss rate of 2.5 t C ha(-1) at that site was 20 t C ha(-1) at the onset of peatland drainage and dropped to less than 1 t C ha(-1) in recent times. Citation: Leifeld, J., M. Steffens, and A. Galego-Sala (2012), Sensitivity of peatland carbon loss to organic matter quality, Geophys. Res. Lett., 39, L14704, doi: 10.1029/2012GL051856.