Stability of organic carbon in deep soil layers controlled by fresh carbon supply
Stability of organic carbon in deep soil layers controlled by fresh carbon supply
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DOI：
10.1038/nature06275
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发表时间：
2007-11-08
期刊：
影响因子：
64.8
通讯作者：
Rumpel, Cornelia
中科院分区：
文献类型：
--
作者：
Fontaine, Sebastien;Barot, Sebastien;Rumpel, Cornelia
世界土壤储存的碳比生物量和大气中存在的碳还要多(1)。然而，人们对控制土壤有机碳库稳定性的因素知之甚少(2-4)，土壤碳库对气候变化的响应仍不确定(5,6)。我们通过结合有机碳的物理和化学特征、土壤孵化和放射性碳测年，研究了一种土壤剖面深层土壤中碳的稳定性。在这里，我们表明，向底土（0.6-0.8 m 深）供应新鲜植物来源的碳刺激了 2,567 +/- 226 年碳的微生物矿化。我们的结果支持了之前提出的想法(7)，即在缺乏新鲜有机碳（土壤微生物的重要能量来源）的情况下，深层土壤层中有机碳的稳定性得以维持。我们认为，新鲜碳供应的缺乏可能会阻止深层土壤中的有机碳库因未来温度变化而分解。然而，土地利用和农业实践中任何增加新鲜碳沿土壤剖面分布的变化(1,8,9)都可能刺激古代埋藏碳的流失。
The world's soils store more carbon than is present in biomass and in the atmosphere(1). Little is known, however, about the factors controlling the stability of soil organic carbon stocks(2-4) and the response of the soil carbon pool to climate change remains uncertain(5,6). We investigated the stability of carbon in deep soil layers in one soil profile by combining physical and chemical characterization of organic carbon, soil incubations and radiocarbon dating. Here we show that the supply of fresh plant-derived carbon to the subsoil (0.6-0.8 m depth) stimulated the microbial mineralization of 2,567 +/- 226-year-old carbon. Our results support the previously suggested idea(7) that in the absence of fresh organic carbon, an essential source of energy for soil microbes, the stability of organic carbon in deep soil layers is maintained. We propose that a lack of supply of fresh carbon may prevent the decomposition of the organic carbon pool in deep soil layers in response to future changes in temperature. Any change in land use and agricultural practice that increases the distribution of fresh carbon along the soil profile(1,8,9) could however stimulate the loss of ancient buried carbon.