PDF(Pubmed)
Abstract：
Climate change is rapidly transforming Arctic landscapes where increasing soil temperatures speed up permafrost thaw. This exposes large carbon stocks to microbial decomposition, possibly worsening climate change by releasing more greenhouse gases. Understanding how microbes break down soil carbon, especially under the anaerobic conditions of thawing permafrost, is important to determine future changes. Here, we studied the microbial community dynamics and soil carbon decomposition potential in permafrost and active layer soils under anaerobic laboratory conditions that simulated an Arctic summer thaw. The microbial and viral compositions in the samples were analyzed based on metagenomes, metagenome-assembled genomes, and metagenomic viral contigs (mVCs). Following the thawing of permafrost, there was a notable shift in microbial community structure, with fermentative Firmicutes and Bacteroidota taking over from Actinobacteria and Proteobacteria over the 60-day incubation period. The increase in iron and sulfate-reducing microbes had a significant role in limiting methane production from thawed permafrost, underscoring the competition within microbial communities. We explored the growth strategies of microbial communities and found that slow growth was the major strategy in both the active layer and permafrost. Our findings challenge the assumption that fast-growing microbes mainly respond to environmental changes like permafrost thaw. Instead, they indicate a common strategy of slow growth among microbial communities, likely due to the thermodynamic constraints of soil substrates and electron acceptors, and the need for microbes to adjust to post-thaw conditions. The mVCs harbored a wide range of auxiliary metabolic genes that may support cell protection from ice formation in virus-infected cells.
OBJECTIVE: As the Arctic warms, thawing permafrost unlocks carbon, potentially accelerating climate change by releasing greenhouse gases. Our research delves into the underlying biogeochemical processes likely mediated by the soil microbial community in response to the wet and anaerobic conditions, akin to an Arctic summer thaw. We observed a significant shift in the microbial community post-thaw, with fermentative bacteria like Firmicutes and Bacteroidota taking over and switching to different fermentation pathways. The dominance of iron and sulfate-reducing bacteria likely constrained methane production in the thawing permafrost. Slow-growing microbes outweighed fast-growing ones, even after thaw, upending the expectation that rapid microbial responses to dominate after permafrost thaws. This research highlights the nuanced and complex interactions within Arctic soil microbial communities and underscores the challenges in predicting microbial response to environmental change.
OBJECTIVE: As the Arctic warms, thawing permafrost unlocks carbon, potentially accelerating climate change by releasing greenhouse gases. Our research delves into the underlying biogeochemical processes likely mediated by the soil microbial community in response to the wet and anaerobic conditions, akin to an Arctic summer thaw. We observed a significant shift in the microbial community post-thaw, with fermentative bacteria like Firmicutes and Bacteroidota taking over and switching to different fermentation pathways. The dominance of iron and sulfate-reducing bacteria likely constrained methane production in the thawing permafrost. Slow-growing microbes outweighed fast-growing ones, even after thaw, upending the expectation that rapid microbial responses to dominate after permafrost thaws. This research highlights the nuanced and complex interactions within Arctic soil microbial communities and underscores the challenges in predicting microbial response to environmental change.
摘要：
气候变化正在迅速改变北极景观，土壤温度的升高加速了多年冻土的融化。这使得大量的碳库暴露于微生物分解，可能会通过释放更多的温室气体来加剧气候变化。了解微生物如何分解土壤碳，特别是在冻土融化的厌氧条件下，对于确定未来的变化很重要。这里,我们研究了模拟北极夏季解冻的厌氧实验室条件下多年冻土和活性层土壤中的微生物群落动态和土壤碳分解潜力。基于宏基因组分析样品中的微生物和病毒组成，宏基因组组装的基因组，和宏基因组病毒重叠群(mVC)。冻土融化后,微生物群落结构发生了显著的变化，在60天的潜伏期内，发酵性Firmicutes和拟杆菌从放线菌和变形菌中接管。铁和硫酸盐还原微生物的增加在限制融化的多年冻土产生甲烷方面具有重要作用，强调微生物群落内的竞争。我们探索了微生物群落的生长策略，发现缓慢生长是活性层和多年冻土的主要策略。我们的发现挑战了快速生长的微生物主要响应环境变化的假设，如永久冻土融化。相反，它们表明了微生物群落缓慢生长的共同策略，可能是由于土壤基质和电子受体的热力学约束，以及微生物适应解冻后条件的需要。mVC具有广泛的辅助代谢基因，可以支持细胞保护免受病毒感染细胞的冰形成。
目标：随着北极变暖，融化永久冻土释放碳，通过释放温室气体可能加速气候变化。我们的研究深入研究了潜在的生物地球化学过程，可能是由土壤微生物群落响应于潮湿和厌氧条件而介导的。类似于北极夏季解冻。我们观察到解冻后微生物群落的显著变化，Firmicutes和拟杆菌等发酵细菌接管并转换为不同的发酵途径。铁和硫酸盐还原细菌的优势可能会限制融化的多年冻土中甲烷的产生。缓慢生长的微生物胜过快速生长的微生物，即使解冻后，推翻了在多年冻土融化后微生物快速反应占主导地位的预期。这项研究强调了北极土壤微生物群落之间微妙而复杂的相互作用，并强调了预测微生物对环境变化反应的挑战。
目标：随着北极变暖，融化永久冻土释放碳，通过释放温室气体可能加速气候变化。我们的研究深入研究了潜在的生物地球化学过程，可能是由土壤微生物群落响应于潮湿和厌氧条件而介导的。类似于北极夏季解冻。我们观察到解冻后微生物群落的显著变化，Firmicutes和拟杆菌等发酵细菌接管并转换为不同的发酵途径。铁和硫酸盐还原细菌的优势可能会限制融化的多年冻土中甲烷的产生。缓慢生长的微生物胜过快速生长的微生物，即使解冻后，推翻了在多年冻土融化后微生物快速反应占主导地位的预期。这项研究强调了北极土壤微生物群落之间微妙而复杂的相互作用，并强调了预测微生物对环境变化反应的挑战。
