ABSTRACT

High-temperature aquifer thermal energy storage (HT-ATES) is a promising technique to reduce the CO₂ footprint of heat supply in the frame of transitioning to renewable energies. However, HT-ATES causes temperature fluctuations in groundwater ecosystems potentially affecting important microbial-mediated ecosystem services. Hence, assessing the impact of increasing temperatures on the structure and functioning of aquifer microbiomes is crucial to evaluate potential environmental risks associated with HT-ATES. In this study, we investigated the effects of temperature variations (12–80°C) on microbial communities and their capacity to mineralize acetate in aerobically incubated sediment sampled from a pristine aquifer. Compared to natural conditions (12°C), increased acetate mineralization rates were observed at 25°C, 37°C and 45°C, whereas mineralization was decelerated at 60°C and absent at 80°C. Sequencing of 16S rRNA genes revealed that the bacterial diversity in acetate-amended and non-acetate-amended sediments decreased with rising temperatures. Distinct communities dominated by bacterial groups affiliated with meso- and thermophilic bacteria established at 45°C and 60°C, respectively, while the number of archaeal phylotypes decreased. The changes in microbial diversity observed at 45°C and 60°C indicate a potential loss of ecosystem functioning, functional redundancy and resilience, while heat storage at 80°C bears the risk of ecological collapse.

中文翻译：

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温度管理可能会影响浅层含水层的碳矿化能力和微生物群落组成

摘要

高温含水层热能存储（HT-ATES）是减少CO ₂的有前途的技术过渡到可再生能源框架中的供热足迹。但是，HT-ATES会引起地下水生态系统的温度波动，从而可能影响重要的微生物介导的生态系统服务。因此，评估温度升高对含水层微生物群落结构和功能的影响对于评估与HT-ATES相关的潜在环境风险至关重要。在这项研究中，我们调查了温度变化（12–80°C）对微生物群落的影响以及它们在从原始含水层中取样的需氧培养沉积物中使乙酸矿化的能力。与自然条件（12°C）相比，在25°C，37°C和45°C时观察到乙酸盐矿化速率增加，而在60°C时矿化速率降低，而在80°C时矿化速率降低。对16S rRNA基因的测序表明，随着温度的升高，醋酸盐改良和非醋酸盐改良沉积物中的细菌多样性降低。不同的群落由分别与分别在45°C和60°C建立的中温和嗜热细菌相关的细菌群控制，而古细菌系统型的数量减少。在45°C和60°C时观察到的微生物多样性变化表明，生态系统功能，功能冗余和弹性可能会损失，而80°C的热量存储存在生态崩溃的风险。而古细菌系统型的数量减少。在45°C和60°C时观察到的微生物多样性变化表明，生态系统功能，功能冗余和弹性可能会损失，而80°C的热量存储存在生态崩溃的风险。而古细菌系统型的数量减少。在45°C和60°C时观察到的微生物多样性变化表明，生态系统功能，功能冗余和弹性可能会损失，而80°C的热量存储存在生态崩溃的风险。