Halomethanes (e.g., CH₃Cl, CH₃Br, CH₃I and CHBr₃) are ozone‐depleting compounds that, in contrast to the human‐made chlorofluorocarbons, marine organisms synthesize naturally. Therefore, their production cannot be totally controlled by human action. However, identifying all their natural sources and understanding their synthesis regulation can help to predict their production rates and their impact on the future recovery of the Earth's ozone layer. Here we show that the synthesis of mono‐halogenated halocarbons CH₃Cl, CH₃Br, and CH₃I is a generalized process in representatives of the major marine heterotrophic bacteria groups. Furthermore, halomethane production was growth rate dependent in all the strains we studied, implying uniform synthesis regulation patterns among bacterioplankton. Using these experimental observations and in situ halomethane concentrations, we further evaluated the potential production rates associated with higher bacterial growth rates in response to global warming in a coastal environment within the Southern California Bight. Our estimates show that a 3°C temperature rise would translate into a 35%–84% increase in halomethane production rate by 2100. Overall, these data suggest that marine heterotrophic bacteria are significant producers of these climate‐relevant gases and that their contribution to the atmospheric halogen budget could increase in the future, impacting the ozone layer recovery.

中文翻译：

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海洋异养细菌中卤代甲烷的生长速率依赖合成及其对臭氧层恢复的影响

卤代甲烷（例如 CH ₃ Cl、CH ₃ Br、CH ₃ I 和 CHBr ₃）是消耗臭氧层的化合物，与人造氯氟烃相比，海洋生物可以自然合成。因此，它们的生产不能完全由人为控制。然而，识别它们的所有天然来源并了解它们的合成规律有助于预测它们的生产率及其对地球臭氧层未来恢复的影响。在这里，我们展示了单卤代卤代烃 CH ₃ Cl、CH ₃ Br 和 CH _3的合成I 是代表主要海洋异养菌群的广义过程。此外，卤代甲烷的产生在我们研究的所有菌株中都依赖于生长速率，这意味着浮游细菌之间的合成调控模式一致。使用这些实验观察和原位卤甲烷浓度，我们进一步评估了与更高的细菌生长率相关的潜在生产率，以应对南加州湾沿海环境中的全球变暖。我们的估计表明，到 2100 年，温度升高 3°C 将转化为卤代甲烷产量增加 35%–84%。总体而言，这些数据表明海洋异养细菌是这些与气候相关的气体的重要生产者，它们对未来大气中的卤素预算可能会增加，从而影响臭氧层的恢复。