The order of magnitude of increased growth, multiplication rate, and decreased sporulation of Bacillus subtilis after exposure to nanotesla magnetic fields (MFs) relative to control samples were observed experimentally. Earth's total magnetic field intensity was reduced from 47.9 ± 0.4 μT to cover the range from 97.5 ± 1.7 nT to 1115 ± 158 nT in eight subsequent experiments by using three pairs of Helmholtz coils combined with Mu-metal shielding. The growth, multiplication rate, sporulation, and potassium content were measured in the probe and control containing B. subtilis cultures after 24 h of exposure to nanotesla and Earth's magnetic fields, respectively. The observed effect is discussed with regard to its possible repercussions on Earth's living species during geomagnetic reversals that occurred when the magnetic field was much weaker than the field that exists today. In addition, effects on future manned voyages into deep space, an environment with reduced magnetic field intensity, are considered.

中文翻译：

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纳特斯拉磁场中枯草芽孢杆菌的生长和孢子形成

通过实验观察到在暴露于纳米特斯拉磁场 (MF) 后枯草芽孢杆菌的生长增加、繁殖率增加和孢子形成减少的数量级。在随后的 8 次实验中，通过使用三对亥姆霍兹线圈结合 Mu 金属屏蔽，地球的总磁场强度从 47.9 ± 0.4 μT 降低到 97.5 ± 1.7 nT 到 1115 ± 158 nT 的范围。在含有枯草芽孢杆菌的探针和对照中测量生长、增殖率、孢子形成和钾含量分别暴露于纳米特斯拉和地球磁场 24 小时后的培养物。讨论了观察到的效应，讨论了它在地磁反转期间对地球生物可能产生的影响，这种反转发生在磁场比今天存在的磁场弱得多的情况下。此外，还考虑了对未来载人深空航行的影响，这是一个磁场强度降低的环境。