中国科学院青藏高原研究所刘勇勤团队，在研究青藏高原冻土中微生物对有机质的潜在转化作用上取得新进展。相关论文于2024年3月18日发表在《中国科学：地球科学》杂志上。

团队人员采用超高分辨率傅里叶变换离子回旋共振质谱(FT-ICR MS)和16S rRNA基因深度测序技术，研究了青藏高原冻土中溶解有机质(DOM)的时间微生物转化。研究发现，在60天的培养过程中，低温结晶中的DOM经历了三个阶段的转化，随着时间的推移，生物利用率逐渐降低。在降解与高H/C_wa和较低O/C_wa相关的DOM分子时，微生物群落在第一周内变化不大。在15-30天中, DOM组成保持稳定，微生物多样性增加。

到第60天，DOM在微生物作用下被转化为更高的顽固状态，具有更高的芳香指数、O/C_wa值和更低的H/C_wa值，其分子中含有更多的杂原子。蓝细菌、拟杆菌门、γ-变形菌门、厚壁菌门、放线菌门等多种微生物类群之间的合作推动了冻土层中DOM的转化。本研究揭示了微生物种群在时间尺度上对冻土层DOM成分的原位转化，为理解微生物在冰川有机碳转化中的作用提供了新的视角。

据了解，微生物在冰川碳循环中起着重要作用。但是，它们是如何转化山地冰川冻土层中的有机质这一问题还有待研究。

附：英文原文

Title: Potential transformation of organic matter by microbes in cryoconite, Tibetan Plateau

Author: Bixi GUO, Yongqin LIU, Kevin Xu ZHONG, Quan SHI, Chen HE, Qiang ZHENG, Ruanhong CAI

Issue&Volume: 2024/03/18

Abstract: Microorganisms play an essential role in the glacier carbon cycle; how they transform organic matter in mountain glacial cryoconite remains to be studied. Here, we applied ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and deep sequencing of 16S rRNA gene, to investigate the temporal microbial transformation of dissolved organic matter (DOM) of the Tibetan Plateau cryoconite. During the 60-day incubation, we found that DOM in cryoconite underwent a three-stage transformation, with decreasing bioavailability over time. The microbial community did not change much in the first week while degrading DOM molecules that were associated with higher H/C_wa and lower O/C_wa. During days 15–30, DOM composition remained stable while microbial diversity increased. By day 60, the DOM was microbially converted into a higher state of recalcitrance, with higher values of aromatic index, O/C_wa, and lower H/C_wa, which contained molecules containing more heteroatoms. Cooperation among various microbial taxa, like Cyanobacteria, Bacteroidota, Gammaproteobacteria, Firmicutes, and Actinobacteriota, drove the DOM transformation in cryoconite. This study sheds light on the in-situ transformation of DOM composition meditated by microbial populations in cryoconite at a temporal scale, providing new insights into understanding the microbial roles in the glacier organic carbon transformation.

DOI: 10.1007/s11430-023-1270-0

Source: https://www.sciengine.com/10.1007/s11430-023-1270-0