Chemolithotrophic microorganisms are key primary producers in hydrothermal environments. However, the complex thermal and compositional gradients that frequently describe these settings commonly obfuscate which reactions are fueling such complex ecosystems. Nonetheless, potential sources of microbial energy can be identified by combining analytical geochemical data from hydrothermal systems and thermodynamic calculations. This approach provides a quantitative assessment of how habitats are shaped by environmental conditions such as temperature, pressure, pH and the concentrations of electron donors and acceptors. In this study, we have calculated the Gibbs energy available from 730 redox reactions in 30 terrestrial, shallow-sea, and deep-sea hydrothermal systems around the world (326 geochemical datasets) to reveal trends in how energy availability can shape hydrothermal ecology. The most energy-yielding (exergonic) reactions were predominantly the reduction of O₂, NO₂⁻, NO₃⁻, and MnO₂ and the oxidation of Fe²⁺, pyrite, CO, and CH₄. In contrast, the reduction of N₂, CO, and CO₂ and oxidation of N₂, Mn²⁺, and NO₂⁻, though still often exergonic, yielded significantly less energy. Also, our results show that, in terms Gibbs energies of reactions, shallow-sea hydrothermal vent systems are more like terrestrial hot springs than deep-sea hydrothermal systems. Per kilogram of water in hydrothermal fluid, energy yields from inorganic redox reactions are much higher in deep-sea hydrothermal systems than in the other systems considered here. Our results provide a comprehensive view of the distribution of energy supplies from redox reactions in high-temperature ecosystems on a global scale.

化学营养微生物是热液环境中的主要初级生产者。然而，经常描述这些环境的复杂的热和成分梯度通常会混淆哪些反应正在推动这种复杂的生态系统。尽管如此，可以通过结合来自热液系统的分析地球化学数据和热力学计算来确定微生物能量的潜在来源。这种方法提供了对栖息地如何受温度、压力、pH 值以及电子供体和受体浓度等环境条件影响的定量评估。在这项研究中，我们计算了 30 个陆地浅海中 730 个氧化还原反应的可用吉布斯能量，和世界各地的深海热液系统（326 个地球化学数据集），以揭示能源可用性如何塑造热液生态的趋势。最能产生能量的（exergonic）反应主要是 O 的减少₂、NO ₂ ^-、NO ₃ ^-和MnO ₂以及Fe ²⁺、黄铁矿、CO 和CH ₄的氧化。相反，N ₂、CO 和CO _{2 的}还原以及N ₂、Mn ²⁺和NO ₂ ^{- 的}氧化，虽然仍然经常exergical，产生明显较少的能量。此外，我们的结果表明，就吉布斯反应能而言，浅海热液喷口系统更像是陆地温泉，而不是深海热液系统。深海热液系统中每千克水的无机氧化还原反应的能量产量远高于此处考虑的其他系统。我们的结果提供了全球范围内高温生态系统中氧化还原反应的能量供应分布的综合视图。