瑞士洛桑联邦理工学院Kohler, Tyler J.和Battin, Tom J.课题组报道了河流微生物代谢对冰川收缩的全球紧急响应。2024年3月1日出版的《自然—地球科学》杂志发表了这项成果。

冰川融化的河流穿过地球的主要山脉，研究团队对154条冰川融化的河流进行资源化学计量和微生物能量学研究，结果发现，这些生态系统及其底栖微生物群总体上受碳和磷的限制。细胞外酶活性模拟的阈值元素比率和低碳利用效率(中位数：0.15)证实了资源限制与底栖微生物的维持代谢一致。空间—时间替代分析表明，冰川收缩将刺激冰川补给河流中的底栖生物初级生产力，从而缓解微生物代谢对碳的限制。

同时，研究发现，提高水流温度可能会刺激微生物的生长(温度敏感性：0.62eV)。因此，随着冰川的缩小，微生物对磷的需求增加，但冰下来源的输入减少，可能会加剧磷的限制。因此，该研究揭示了世界冰川补给河流向自养生物的“绿色转变”，这涉及到微生物能量学的变化。

研究人员表示，大多数冰冻圈生态系统的能量是有限的。它们的能量如何对气候变化作出反应在很大程度上仍然未知。对于冰川补给的河流来说尤其如此，这些河流与冰冻圈相连，形成了地球上一些最大的河流系统。

附：英文原文

Title: Global emergent responses of stream microbial metabolism to glacier shrinkage

Author: Kohler, Tyler J., Bourquin, Massimo, Peter, Hannes, Yvon-Durocher, Gabriel, Sinsabaugh, Robert L., Deluigi, Nicola, Styllas, Michael, Battin, Tom J.

Issue&Volume: 2024-03-01

Abstract: Most cryospheric ecosystems are energy limited. How their energetics will respond to climate change remains largely unknown. This is particularly true for glacier-fed streams, which interface with the cryosphere and initiate some of Earth’s largest river systems. Here, by studying resource stoichiometry and microbial energetics in 154 glacier-fed streams sampled by the Vanishing Glaciers project across Earth’s major mountain ranges, we show that these ecosystems and their benthic microbiome are overall carbon and phosphorus limited. Threshold elemental ratios and low carbon use efficiencies (median: 0.15) modelled from extracellular enzymatic activities corroborate resource limitation in agreement with maintenance metabolism of benthic microorganisms. Space-for-time substitution analyses suggest that glacier shrinkage will stimulate benthic primary production in glacier-fed streams, thereby relieving microbial metabolism from carbon limitation. Concomitantly, we find that increasing streamwater temperature will probably stimulate microbial growth (temperature sensitivity: 0.62eV). Consequently, elevated microbial demands for phosphorus, but diminishing inputs from subglacial sources, may intensify phosphorus limitation as glaciers shrink. Our study thus unveils a ‘green transition’ towards autotrophy in the world’s glacier-fed streams, entailing shifts in the energetics of their microorganisms.

DOI: 10.1038/s41561-024-01393-6

Source: https://www.nature.com/articles/s41561-024-01393-6