High hydrostatic pressure (HHP) is a common factor in the deep sea and provides an ignorable parameter of consideration in all studies related to deep life. High-temperature environments in the deep sea, mainly including hydrothermal vents and deep sediments in the subseafloor, support enormous amounts of biomass, productivity, and diversity of life. Many microbes living there are usually (hyper)thermophilic piezophiles, which cope with the dual stresses of high temperature and HHP at the same time and playing significant roles in geochemical elemental cycling. Knowledge of the upper temperature limit of life under deep-sea HHP conditions can help us to estimate the boundary of the biosphere and explore its habitability on Earth and in extraterrestrial areas, but uncertainties remain. Here, we have summarized the current known knowledge of physiological correlations between high temperature and HHP, as well as the effects of HHP on cells at high temperature. These effects mainly comprise two aspects: biological integrity and metabolic feasibility. The former has been investigated in many studies on various microorganisms, from which we can draw a general conclusion that HHP helps cells maintain biological integrity under high temperature. For the latter, existing studies have provided clues suggesting that both high temperature and HHP challenge metabolic feasibility, but it is still difficult to draw conclusions on the additive effects on metabolism due to the lack of systematic analysis. Here, we also propose a series of questions for further investigation and called for more attention on metabolic responses to high temperature and HHP; this could provide a direct bridge between geochemistry and ecology, help us to understand the microbial functions in the deep biosphere and allow us to estimate the boundaries of life and habitats.

高静水压力 (HHP) 是深海中的一个常见因素，并且在所有与深海生命相关的研究中提供了一个可忽略的参数。深海的高温环境，主要包括海底的热液喷口和深层沉积物，支撑着大量的生物量、生产力和生物多样性。生活在那里的许多微生物通常是（超）嗜热嗜压菌，它们同时应对高温和高温高压的双重压力，在地球化学元素循环中发挥着重要作用。了解深海高温高压条件下生命的温度上限可以帮助我们估计生物圈的边界并探索其在地球和外星区域的宜居性，但不确定性仍然存在。这里，我们总结了目前已知的高温与 HHP 之间生理相关性的知识，以及 HHP 在高温下对细胞的影响。这些影响主要包括两个方面：生物完整性和代谢可行性。前者在对各种微生物的许多研究中得到了研究，从中我们可以得出一个普遍的结论，即HHP有助于细胞在高温下保持生物完整性。对于后者，现有研究已提供线索，表明高温和高温高压均挑战代谢可行性，但由于缺乏系统分析，仍难以得出对代谢的累加效应的结论。这里，我们还提出了一系列需要进一步研究的问题，并呼吁更多关注对高温和HHP的代谢反应；这可以提供地球化学和生态之间的直接桥梁，帮助我们了解深层生物圈中的微生物功能，并使我们能够估计生命和栖息地的界限。