Succession of N cycling processes in biological soil crusts on a Central European inland dune
Succession of N cycling processes in biological soil crusts on a Central European inland dune
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DOI：
10.1111/j.1574-6941.2012.01459.x
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发表时间：
2013-01-01
影响因子：
4.2
通讯作者：
Zeyer, Josef
中科院分区：
文献类型：
--
作者：
Brankatschk, Robert;Fischer, Thomas;Zeyer, Josef
生物土壤结皮（BSCs）是世界范围内存在的微生物组合，通过氮和碳的积累促进生态系统的发展。过去对平衡计分卡生态系统内的氮周转进行了深入研究；然而，在平衡计分卡发展过程中，N周期的变化以前没有被调查过。我们的目标是通过相应功能基因的丰度（括号内）和潜在的酶活性来表征N循环的发育；我们重点研究了四个过程：固氮（nifH），矿化作为蛋白质水解和几丁质水解（chiA），硝化（amoA）和反硝化（nosZ）。我们从BSC发育的四个阶段和位于德国内陆沙丘上的Corynephorus canescens生根区的参考资料中取样。BSC的发育与叶绿素、有机碳和氮含量的增加有关，潜在活性增加，且在发育的BSC中最高。同样，功能基因的丰度也增加了。我们提出并讨论了N过程演替的三个阶段。首先，异养阶段（不含BSCs的流动砂）由矿化活动主导。其次，在过渡阶段（初始BSCs）， N积累，潜在的硝化和反硝化活性增加。第三，发展阶段（建立的BSCs和参考）的特点是硝化作用占主导地位。
Biological soil crusts (BSCs) are microbial assemblages that occur worldwide and facilitate ecosystem development by nitrogen (N) and carbon accumulation. N turnover within BSC ecosystems has been intensively studied in the past; however, shifts in the N cycle during BSC development have not been previously investigated. Our aim was to characterise N cycle development first by the abundance of the corresponding functional genes (in brackets) and second by potential enzyme activities; we focussed on the four processes: N fixation (nifH), mineralisation as proteolysis and chitinolysis (chiA), nitrification (amoA) and denitrification (nosZ). We sampled from four phases of BSC development and from a reference located in the rooting zone of Corynephorus canescens, on an inland dune in Germany. BSC development was associated with increasing amounts of chlorophyll, organic carbon and N. Potential activities increased and were highest in developed BSCs. Similarly, the abundance of functional genes increased. We propose and discuss three stages of N process succession. First, the heterotrophic stage (mobile sand without BSCs) is dominated by mineralisation activity. Second, during the transition stage (initial BSCs), N accumulates, and potential nitrification and denitrification activity increases. Third, the developed stage (established BSCs and reference) is characterised by the dominance of nitrification.