Cockell Charles S, Raven John A
Centre for Earth, Planetary, Space and Astronomical Research, Open University, Milton Keynes, UK.
Philos Trans A Math Phys Eng Sci. 2007 Jul 15;365(1856):1889-901. doi: 10.1098/rsta.2007.2049.
The trace gas ozone, produced in the present-day stratosphere, acts as a screen for UV radiation between 195 and approximately 290 nm, depending on its column abundance. On the anoxic Archaean Earth, such an ozone screen would not have existed. Although the presence of other screens, such as an organic haze, might have ameliorated the UV radiation flux, even assuming the worst-case scenario (no UV screen), it can be shown that early land masses and the photic zone of the oceans could have been colonized, suggesting that: (i) high UV radiation would not have prevented the colonization of land and (ii) it is unlikely that the fossil record can be used to constrain estimates of the UV radiation environment of the early Earth (although geochemical approaches and the study of extrasolar planetary atmospheres are likely to provide empirical constraints on the early photobiological environment).
现今平流层中产生的痕量气体臭氧，根据其柱丰度，可作为195至约290纳米之间紫外线辐射的屏障。在缺氧的太古宙地球，这样的臭氧屏障并不存在。尽管可能存在其他屏障，如有机霾，或许能减弱紫外线辐射通量，但即便假设最坏的情况（没有紫外线屏障），也能证明早期陆地和海洋光合带本可被殖民，这表明：（i）高紫外线辐射不会阻止陆地的殖民化，且（ii）化石记录不太可能用于限制对早期地球紫外线辐射环境的估计（尽管地球化学方法和对系外行星大气的研究可能会为早期光生物学环境提供实证约束）。
