Fungi mediate long term sequestration of carbon and nitrogen in soil through their priming effect
Fungi mediate long term sequestration of carbon and nitrogen in soil through their priming effect
复制标题
DOI：
10.1016/j.soilbio.2010.09.017
复制
发表时间：
2011-01-01
影响因子：
9.7
通讯作者：
Maron, P. A.
中科院分区：
文献类型：
--
作者：
Fontaine, S.;Henault, C.;Maron, P. A.
土壤微生物具有利用新鲜碳源分解老腐殖土有机质（SOM）的能力，这一现象被称为启动效应（PE）。然而，努力确定这种PE的土壤碳和氮动态的后果是在他们的早期阶段。此外，人们对所涉及的微生物种群知之甚少。在这里，我们探讨的后果，PE SOM动态和矿质氮的可用性在土壤培养实验（161天），结合供应的双标记（C-13和C-14）纤维素和矿质营养。利用分子指纹技术（FAMES和B-和F-ARISA）研究了PE中涉及的微生物组。我们发现，由PE控制的SOM池的平均停留时间从3130年的底土，新鲜碳的可用性是非常低的，在表层17-39年。这一结果表明，这种腐殖土碳库的分解是严格依赖于新鲜的C的存在下，并不是一个积极可行的手段访问C的土壤微生物。我们还认为，真菌是纤维素分解和诱导PE的主要演员，他们调整自己的降解活动的养分供应。真菌的主要作用可以解释为它们作为菌丝体生长的能力，这使得它们能够探索土壤空间并开采大量的SOM。最后，我们的研究结果支持存在一个银行的机制，调节养分和碳封存在土壤中：PE是低的，当养分的可用性是高的，允许封存的养分和碳;相反，微生物从SOM释放养分时，养分的可用性低。这种库机制可能有助于同步的可溶性养分的供应，植物的需求，并有助于长期的SOM积累的生态系统。(C)2010爱思唯尔有限公司保留所有权利。
It is increasingly recognized that soil microbes have the ability to decompose old recalcitrant soil organic matter (SOM) by using fresh carbon as a source of energy, a phenomena called priming effect (PE). However, efforts to determine the consequences of this PE for soil carbon and nitrogen dynamics are in their early stage. Moreover, little is known about the microbial populations involved. Here we explore the consequences of PE for SOM dynamics and mineral nitrogen availability in a soil incubation experiment (161 days), combining the supply of dual-labeled (C-13 and C-14) cellulose and mineral nutrients. The microbial groups involved in PE were investigated using molecular fingerprinting techniques (FAMES and B- and F-ARISA). We show that mean residence time of SOM pool controlled by the PE decreased from 3130 years in the subsoil, where the availability of fresh carbon is very low, to 17-39 years in the surface layer. This result suggests that the decomposition of this recalcitrant soil C pool is strictly dependent on the presence of fresh C and is not an energetically viable mean of accessing C for soil microbes. We also suggest that fungi are the predominant actors of cellulose decomposition and induced PE and they adjust their degradation activity to nutrient availability. The predominant role of fungi can be explained by their ability to grow as mycelium which allows them to explore soil space and mine large reserve of SOM. Finally, our results support the existence of a bank mechanism that regulates nutrient and carbon sequestration in soil: PE is low when nutrient availability is high, allowing sequestration of nutrients and carbon; in contrast, microbes release nutrients from SOM when nutrient availability is low. This bank mechanism may help to synchronize the availability of soluble nutrients to plant requirement and contribute to long-term SOM accumulation in ecosystems. (C) 2010 Elsevier Ltd. All rights reserved.