The nitrogen cycle in cryoconites: naturally occurring nitrification-denitrification granules on a glacier.
The nitrogen cycle in cryoconites: naturally occurring nitrification-denitrification granules on a glacier.
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DOI：
10.1111/1462-2920.12543
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发表时间：
2014-10
影响因子：
5.1
通讯作者：
T. Segawa;S. Ishii;N. Ohte;Ayumi Akiyoshi;Akinori Yamada;F. Maruyama;Zhong-qin Li;Yuichi Hongoh
中科院分区：
文献类型：
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作者：
T. Segawa;S. Ishii;N. Ohte;Ayumi Akiyoshi;Akinori Yamada;F. Maruyama;Zhong-qin Li;Yuichi Hongoh
冰尘是冰川表面常见的微生物聚集体，它们往往呈球形，颗粒状。虽然有人认为冰尘颗粒中的微生物在冰川生态系统中发挥着重要作用，但有关其群落结构的信息仍然有限，其功能仍不清楚。在这里，我们提出的证据发生在中亚冰川上的冰屑颗粒氮循环。我们通过数字聚合酶链反应（PCR）检测了冰孢子颗粒中固氮、硝化和反硝化的标记基因，而数字逆转录PCR分析表明，只有硝化和反硝化的标记基因被大量转录。同位素比值分析也表明了硝化作用的发生;冰川表面融水中的硝酸盐是生物来源的，而雪中的硝酸盐则是大气来源的。amoA序列和16 S核糖体RNA焦磷酸测序分析表明，该冰川上的主要硝化细菌属于亚硝化单胞菌目。我们的研究结果表明，强烈的碳和氮循环的硝化，硝化和蓝藻支持丰富和活跃的微生物在亚洲冰川。
Cryoconites are microbial aggregates commonly found on glacier surfaces where they tend to take spherical, granular forms. While it has been postulated that the microbes in cryoconite granules play an important role in glacier ecosystems, information on their community structure is still limited, and their functions remain unclear. Here, we present evidence for the occurrence of nitrogen cycling in cryoconite granules on a glacier in Central Asia. We detected marker genes for nitrogen fixation, nitrification and denitrification in cryoconite granules by digital polymerase chain reaction (PCR), while digital reverse transcription PCR analysis revealed that only marker genes for nitrification and denitrification were abundantly transcribed. Analysis of isotope ratios also indicated the occurrence of nitrification; nitrate in the meltwater on the glacier surface was of biological origin, while nitrate in the snow was of atmospheric origin. The predominant nitrifiers on this glacier belonged to the order Nitrosomonadales, as suggested by amoA sequences and 16S ribosomal RNA pyrosequencing analysis. Our results suggest that the intense carbon and nitrogen cycles by nitrifiers, denitrifiers and cyanobacteria support abundant and active microbes on the Asian glacier.