Impact shocked rocks as protective habitats on an anoxic early Earth

On Earth, microorganisms living under intense ultraviolet (UV) radiation stress can adopt endolithic lifestyles, growing within cracks and pore spaces in rocks. Intense UV irradiation encountered by microbes leads to death and significant damage to biomolecules, which also severely diminishes the li...

Full description

Saved in:
Bibliographic Details
Published in:International journal of astrobiology 2015-01, Vol.14 (1), p.115-122
Main Authors: Bryce, Casey C., Horneck, Gerda, Rabbow, Elke, Edwards, Howell G. M., Cockell, Charles S.
Format: Article
Language:English
Subjects:
Earth
Irradiation
Microorganisms
Rocks
Ultraviolet radiation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:On Earth, microorganisms living under intense ultraviolet (UV) radiation stress can adopt endolithic lifestyles, growing within cracks and pore spaces in rocks. Intense UV irradiation encountered by microbes leads to death and significant damage to biomolecules, which also severely diminishes the likelihood of detecting signatures of life. Here we show that porous rocks shocked by asteroid or comet impacts provide protection for phototrophs and their biomolecules during 22 months of UV radiation exposure outside the International Space Station. The UV spectrum used approximated the high-UV flux on the surface of planets lacking ozone shields such as the early Earth. These data provide a demonstration that endolithic habitats can provide a refugium from the worst-case UV radiation environments on young planets and an empirical refutation of the idea that early intense UV radiation fluxes would have prevented phototrophs without the ability to form microbial mats or produce UV protective pigments from colonizing the surface of early landmasses.
ISSN:1473-5504
1475-3006
DOI:10.1017/S1473550414000123