Impact of inorganic nitrogen additions on microbes in biological soil crusts
Impact of inorganic nitrogen additions on microbes in biological soil crusts
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无机氮添加对生物土壤结皮微生物的影响
DOI：
10.1016/j.soilbio.2015.06.004
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发表时间：
2015-09
影响因子：
9.7
通讯作者：
Xiaofei Ma
中科院分区：
文献类型：
--
作者：
Jieqiong Su;Xinrong Li;Guoxiong Chen;Xiaofei Ma
许多研究表明，氮素有效性的变化影响了各种陆地系统中土壤微生物群落的多样性和组成，但对生物土壤结皮(BSCs)特有微生物对增加氮素添加的响应知之甚少。经过7年的田间试验，地衣结皮中的细菌多样性随着无机氮施用量的增加呈线性下降(环境氮沉降量；低氮施用量，3.5g·N-m−2y−1；中等施氮量，7.0g·N-m−2y−1；高N施用量，14.0 g·N-m−2y−1)，而真菌多样性呈现出明显的格局，低施氮量结皮的多样性高于其他结皮。焦解测序数据显示，细菌群落向添加适量氮(低氮和中氮)的蓝藻转移，向放线菌和变形杆菌转移，向添加过量氮(高N)的蓝藻转移。我们的结果表明，土壤pH和土壤有机碳(C)一起构成了细菌群落，并增加了N。在真菌群落中，子囊菌相对丰度随施N量的增加而增加，随施氮量的增加而减少，但增加施氮量有利于担子菌的生长，这可能归因于施氮量增加时底物利用率增加，木质素含量降低，纤维素含量增加。土壤细菌/真菌比值在施氮后明显高于对照，说明在施氮后，地衣结皮中细菌生物量明显高于真菌生物量，在过量施氮条件下表现得尤为明显。由于细菌和真菌是生物干细胞的重要组成部分和重要分解者，细菌和真菌群落的变化可能对生物干细胞的形成和持续以及荒漠生态系统中碳的循环和储存产生影响。
Many studies have shown that changes in nitrogen (N) availability affect the diversity and composition of soil microbial community in a variety of terrestrial systems, but less is known about the responses of microbes specific to biological soil crusts (BSCs) to increasing N additions. After seven years of field experiment, the bacterial diversity in lichen-dominated crusts decreased linearly with increasing inorganic N additions (ambient N deposition; low N addition, 3.5 g N m−2y−1; medium N addition, 7.0 g N m−2y−1; high N addition, 14.0 g N m−2y−1), whereas the fungal diversity exhibited a distinctive pattern, with the low N-added crust containing a higher diversity than the other crusts. Pyrosequencing data revealed that the bacterial community shifted to more Cyanobacteria with modest N additions (low N and medium N) and to more Actinobacteria and Proteobacteria and much less Cyanobacteria with excess N addition (high N). Our results suggest that soil pH, together with soil organic carbon (C), structures the bacterial communities with N additions. Among the fungal communities, the relative abundance of Ascomycota increased with modest N but decreased with excess N. However, increasing N additions favored Basidiomycota, which may be ascribed to increases in substrate availability with low lignin and high cellulose contents under elevated N conditions. Bacteria/fungi ratios were higher in the N-added samples than in the control, suggesting that the bacterial biomass tends to dominate over that of fungi in lichen-dominated crusts after N additions, which is especially evident in the excess N condition. Because bacteria and fungi are important components and important decomposers in BSCs, the alterations of the bacterial and fungal communities may have implications in the formation and persistence of BSCs and the cycling and storage of C in desert ecosystems.
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影响因子：
2.9
作者：
Entwistle, Elizabeth M.;Zak, Donald R.;Edwards, Ivan P.
通讯作者：
Edwards, Ivan P.
影响因子：
9.7
作者：
Allison, Steven D.;Gartner, Tracy B.;Treseder, Kathleen
通讯作者：
Treseder, Kathleen
影响因子：
9.7
作者：
M. Waldrop;D. Zak;R. Sinsabaugh
通讯作者：
M. Waldrop;D. Zak;R. Sinsabaugh
影响因子：
4.9
作者：
S. Schulz;R. Brankatschk;A. Dümig;I. Kögel‐Knabner;M. Schloter;J. Zeyer
通讯作者：
S. Schulz;R. Brankatschk;A. Dümig;I. Kögel‐Knabner;M. Schloter;J. Zeyer
影响因子：
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作者：
Laiz, L.;Miller, A. Z.;Saiz-Jimenez, C.
通讯作者：
Saiz-Jimenez, C.