InBioS - Centre for Protein Engineering, University of Liège, Allée du Six Août 13, B6a, Quartier Agora, Sart-Tilman, 4000, Liège, Belgium.
Department of Microbiology, University of Helsinki, P.O. Box 56 (Viikinkaari 9), 00014, Helsinki, Finland.
Microb Ecol. 2019 Jan;77(1):136-147. doi: 10.1007/s00248-018-1203-3. Epub 2018 May 23.
Cyanobacteria are important colonizers of recently deglaciated proglacial soil but an in-depth investigation of cyanobacterial succession following glacier retreat has not yet been carried out. Here, we report on the successional trajectories of cyanobacterial communities in biological soil crusts (BSCs) along a 100-year deglaciation gradient in three glacier forefields in central Svalbard, High Arctic. Distance from the glacier terminus was used as a proxy for soil age (years since deglaciation), and cyanobacterial abundance and community composition were evaluated by epifluorescence microscopy and pyrosequencing of partial 16S rRNA gene sequences, respectively. Succession was characterized by a decrease in phylotype richness and a marked shift in community structure, resulting in a clear separation between early (10-20 years since deglaciation), mid (30-50 years), and late (80-100 years) communities. Changes in cyanobacterial community structure were mainly connected with soil age and associated shifts in soil chemical composition (mainly moisture, SOC, SMN, K, and Na concentrations). Phylotypes associated with early communities were related either to potentially novel lineages (< 97.5% similar to sequences currently available in GenBank) or lineages predominantly restricted to polar and alpine biotopes, suggesting that the initial colonization of proglacial soil is accomplished by cyanobacteria transported from nearby glacial environments. Late communities, on the other hand, included more widely distributed genotypes, which appear to establish only after the microenvironment has been modified by the pioneering taxa.
蓝藻是最近冰川退缩后冰碛土壤的重要定殖者，但对冰川后退后蓝藻演替的深入调查尚未进行。在这里，我们报告了在斯瓦尔巴群岛中部三个冰川前缘的生物土壤结皮（BSC）中蓝藻群落的演替轨迹，这是一个 100 年的冰川退缩梯度。距冰川末端的距离被用作土壤年龄（冰川退缩以来的年数）的替代物，分别通过荧光显微镜和部分 16S rRNA 基因序列的焦磷酸测序来评估蓝藻丰度和群落组成。演替的特征是表型丰富度下降和群落结构明显变化，导致早期（冰川退缩后 10-20 年）、中期（30-50 年）和晚期（80-100 年）群落之间的明显分离。蓝藻群落结构的变化主要与土壤年龄以及与土壤化学组成的相关变化（主要是水分、SOC、SMN、K 和 Na 浓度）有关。与早期群落相关的分类群要么与潜在的新谱系（<97.5%与 GenBank 中现有序列相似）有关，要么与主要局限于极地和高山生物区系的谱系有关，这表明冰碛土壤的初始定殖是由从附近冰川环境中运输的蓝藻完成的。另一方面，晚期群落包括分布更广的基因型，这些基因型似乎只在先驱类群改变微环境后才建立。
