Girard Catherine, Vincent Warwick F, Culley Alexander I
Département de biochimie, de microbiologie et de bio-informatique & Institut de biologie intégrative et des systèmes (IBIS), Université Laval, Québec, QC, Canada.
Centre d'études nordiques (CEN), Québec, QC, Canada.
ISME Commun. 2023 Sep 26;3(1):105. doi: 10.1038/s43705-023-00313-w.
Arctic climate change is leading to sea-ice attrition in the Last Ice Area along the northern coast of Canada and Greenland, but less attention has been given to the associated land-based ecosystems. Here we evaluated bacterial community structure in a hydrologically coupled cryo-ecosystem in the region: Thores Glacier, proglacial Thores Lake, and its outlet to the sea. Deep amplicon sequencing revealed that Polaromonas was ubiquitous, but differed genetically among diverse niches. Surface glacier-ice was dominated by Cyanobacteria, while the perennially ice-capped, well-mixed water column of Thores Lake had a unique assemblage of Chloroflexi, Actinobacteriota, and Planctomycetota. Species richness increased downstream, but glacier microbes were little detected in the lake, suggesting strong taxonomic sorting. Ongoing climate change and the retreat of Thores Glacier would lead to complete drainage and loss of the lake microbial ecosystem, indicating the extreme vulnerability of diverse cryohabitats and unique microbiomes in the Last Ice coastal margin.
北极气候变化正导致加拿大北部海岸和格陵兰岛沿岸最后一个冰区的海冰损耗，但对相关陆地生态系统的关注较少。在此，我们评估了该地区一个水文耦合的低温生态系统中的细菌群落结构：托雷斯冰川、冰川前缘的托雷斯湖及其入海河口。深度扩增子测序显示，极地单胞菌属无处不在，但在不同生态位之间存在基因差异。表面冰川冰以蓝藻为主，而常年被冰覆盖、充分混合的托雷斯湖水柱中含有绿弯菌门、放线菌门和浮霉菌门的独特组合。物种丰富度在下游增加，但在湖中很少检测到冰川微生物，这表明存在强烈的分类分选现象。持续的气候变化和托雷斯冰川的退缩将导致湖泊微生物生态系统完全排水并丧失，这表明最后一个冰区沿海边缘各种低温栖息地和独特微生物群落极易受到影响。
