LOCEAN Laboratory, Sorbonne Université-CNRS-IRD-MNHN, Paris, France.
LMD-IPSL, CNRS, Ecole Normale Supérieure/PSL Research University, Ecole Polytechnique, Sorbonne Université, Paris, France.
Glob Chang Biol. 2023 Feb;29(4):982-997. doi: 10.1111/gcb.16514. Epub 2022 Nov 20.
Our understanding of how increasing atmospheric CO and climate change influences the marine CO system and in turn ecosystems has increasingly focused on perturbations to carbonate chemistry variability. This variability can affect ocean-climate feedbacks and has been shown to influence marine ecosystems. The seasonal variability of the ocean CO system has already changed, with enhanced seasonal variations in the surface ocean pCO over recent decades and further amplification projected by models over the 21st century. Mesocosm studies and CO vent sites indicate that diurnal variability of the CO system, the amplitude of which in extreme events can exceed that of mean seasonal variability, is also likely to be altered by climate change. Here, we modified a global ocean biogeochemical model to resolve physically and biologically driven diurnal variability of the ocean CO system. Forcing the model with 3-h atmospheric outputs derived from an Earth system model, we explore how surface ocean diurnal variability responds to historical changes and project how it changes under two contrasting 21st-century emission scenarios. Compared to preindustrial values, the global mean diurnal amplitude of pCO increases by 4.8 μatm (+226%) in the high-emission scenario but only 1.2 μatm (+55%) in the high-mitigation scenario. The probability of extreme diurnal amplitudes of pCO and [H ] is also affected, with 30- to 60-fold increases relative to the preindustrial under high 21st-century emissions. The main driver of heightened pCO diurnal variability is the enhanced sensitivity of pCO to changes in temperature as the ocean absorbs atmospheric CO . Our projections suggest that organisms in the future ocean will be exposed to enhanced diurnal variability in pCO and [H ], with likely increases in the associated metabolic cost that such variability imposes.
我们对大气 CO 和气候变化如何影响海洋 CO 系统，进而影响生态系统的理解，越来越关注碳酸盐化学变化的干扰。这种可变性会影响海洋气候反馈，并已被证明会影响海洋生态系统。海洋 CO 系统的季节性变化已经发生了变化，近几十年来，表层海洋 pCO 的季节性变化增强，模型预测 21 世纪还会进一步放大。中观宇宙研究和 CO 通风口表明，CO 系统的日变化幅度，在极端事件中日变化幅度可能超过季节性变化幅度，也可能因气候变化而改变。在这里，我们修改了一个全球海洋生物地球化学模型，以解决物理和生物驱动的海洋 CO 系统日变化。通过使用来自地球系统模型的 3 小时大气输出来驱动模型，我们探讨了表层海洋日变化如何响应历史变化，并预测了在两种对比的 21 世纪排放情景下它将如何变化。与工业化前相比，高排放情景下全球平均 pCO 日振幅增加了 4.8 μatm（+226%），而高缓解情景下仅增加了 1.2 μatm（+55%）。极端 pCO 和[H ]日振幅的概率也受到影响，在高排放情景下，与工业化前相比，增加了 30 到 60 倍。pCO 日变化幅度增加的主要驱动因素是，海洋吸收大气 CO 时，pCO 对温度变化的敏感性增强。我们的预测表明，未来海洋中的生物将面临 pCO 和[H ]的日变化幅度增强，这可能会增加相关代谢成本。
