The Interplanetary Exchange of Photosynthesis

Cockell, Charles S.

doi:10.1007/s11084-007-9112-3

Cited by 48 publications

(43 citation statements)

References 71 publications

(77 reference statements)

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“…The final scenario considered is the possibility of a planetary system harbouring two rocky planets, each with a photosynthetic biosignature (Cockell 2008) -a binary photosynthesis system. Such a system could occur through the independent evolution of photosynthesis on each of two planets or the transfer of photosynthesis from one planet on which photosynthesis has evolved to another.…”

Section: A Binary Photosynthesis Systemmentioning

confidence: 99%

“…Without knowledge of the probability of the evolution of photosynthesis (Rothschild 2008), the probability of the evolution of photosynthesis on two planetary bodies cannot be assessed. The second mechanism, the interplanetary transfer of photosynthesis, is, however, experimentally testable (Cockell 2008). The notion of the potential exchange of photosynthesis between two planets within a single star system may not be unwarranted speculation.…”

Section: A Binary Photosynthesis Systemmentioning

confidence: 99%

“…This has proven to be experimentally testable. Under the auspices of the ESA (European Space Agency) STONE experiment, designed to investigate the survival of artificial meteorites during atmospheric entry , we studied the effects of atmospheric entry on photosynthetic organisms (Cockell 2008).…”

Section: Survival Of Atmospheric Entrymentioning

confidence: 99%

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Planetary targets in the search for extrasolar oxygenic photosynthesis

Cockell

Raven

Kaltenegger

et al. 2009

Plant Ecology & Diversity

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Background:In the coming decades space telescopes will be constructed that will attempt to find the gaseous products of oxygenic photosynthesis, the most promising biosignatures of life, in the atmospheres of temperate Earth-like planets orbiting distant stars. Aims: This paper aims to provide a synthesis of the range of feasible targets -either planets or their satellites -that could harbour photosynthesis. Methods: We calculated photosynthetically active radiation (PAR) fluxes on a diversity of planetary bodies including those receiving direct light from a single star, similarly to the Earth, and investigated the potential of these fluxes to support photosynthesis. Results: All main sequence stars emit radiation that is capable of supporting photosynthesis on Earth-like planets. We discuss tidally-locked M star planets as a special case. Less conventional targets for searches include large moons orbiting gas giant planets, which receive reflected light from their host planets and from the host star, planets in stable orbits in binary star systems, and the search for two planets within the same star system with photosynthetic signatures. Conclusions: A diversity of planetary bodies are targets in the search for extrasolar photosynthesis. The demonstration that many or none of these candidate planetary bodies harbour photosynthesis would be an important conclusion in understanding the evolution and prevalence of photosynthesis.

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Section: A Binary Photosynthesis Systemmentioning

confidence: 99%

Section: A Binary Photosynthesis Systemmentioning

confidence: 99%

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Planetary targets in the search for extrasolar oxygenic photosynthesis

Cockell

Raven

Kaltenegger

et al. 2009

Plant Ecology & Diversity

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“…Richter (1865) and Arrhenius (1903) first proposed the panspermia theory, which speculates about the transfer of life between planets. Although panspermia still remains little more than an idea and there is no evidence that it has occurred, the various steps required for the transfer of organisms from one planet to another have been the focus of experimental testing (Cockell, 2008). This technical availability has led to several studies, either under simulated space conditions (Buecker and Horneck, 1970;Mancinelli and Klovstad, 2000;De la Torre et al, 2003) or in spaceflight experiments (Horneck, 1993;Fajardo-Cavalzos et al, 2005;Sancho et al, 2007;Horneck et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Whole Lichen Thalli Survive Exposure to Space Conditions: Results of Lithopanspermia Experiment withAspicilia fruticulosa

et al. 2011

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The Lithopanspermia space experiment was launched in 2007 with the European Biopan facility for a 10-day spaceflight on board a Russian Foton retrievable satellite. Lithopanspermia included for the first time the vagrant lichen species Aspicilia fruticulosa from Guadalajara steppic highlands (Central Spain), as well as other lichen species. During spaceflight, the samples were exposed to selected space conditions, that is, the space vacuum, cosmic radiation, and different spectral ranges of solar radiation (λ ≥ 110, ≥200, ≥290, or ≥400 nm, respectively). After retrieval, the algal and fungal metabolic integrity of the samples were evaluated in terms of chlorophyll a fluorescence, ultrastructure, and CO(2) exchange rates. Whereas the space vacuum and cosmic radiation did not impair the metabolic activity of the lichens, solar electromagnetic radiation, especially in the wavelength range between 100 and 200 nm, caused reduced chlorophyll a yield fluorescence; however, there was a complete recovery after 72 h of reactivation. All samples showed positive rates of net photosynthesis and dark respiration in the gas exchange experiment. Although the ultrastructure of all flight samples showed some probable stress-induced changes (such as the presence of electron-dense bodies in cytoplasmic vacuoles and between the chloroplast thylakoids in photobiont cells as well as in cytoplasmic vacuoles of the mycobiont cells), we concluded that A. fruticulosa was capable of repairing all space-induced damage. Due to size limitations within the Lithopanspermia hardware, the possibility for replication on the sun-exposed samples was limited, and these first results on the resistance of the lichen symbiosis A. fruticulosa to space conditions and, in particular, on the spectral effectiveness of solar extraterrestrial radiation must be considered preliminary. Further testing in space and under space-simulated conditions will be required. Results of this study indicate that the quest to discern the limits of lichen symbiosis resistance to extreme environmental conditions remains open.

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“…Each phase of interplanetary transfer is fraught with its own particular hazards to the survival of life. (reviewed in Mileikowsky et al, 2000;Nicholson et al, 2000;Clark, 2001;Horneck et al, 2002;Cockell, 2008;Nicholson, 2009).…”

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confidence: 99%

Bacterial Spores in Granite Survive Hypervelocity Launch by Spallation: Implications for Lithopanspermia

et al. 2009

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Bacterial spores are considered good candidates for endolithic life-forms that could survive interplanetary transport by natural impact processes, i.e., lithopanspermia. Organisms within rock can only embark on an interplanetary journey if they survive ejection from the surface of the donor planet and the associated extremes of compressional shock, heating, and acceleration. Previous simulation experiments have measured each of these three stresses more or less in isolation of one another, and results to date indicate that spores of the model organism Bacillus subtilis can survive each stress applied singly. Few simulations, however, have combined all three stresses simultaneously. Because considerable experimental and theoretical evidence supports a spallation mechanism for launch, we devised an experimental simulation of launch by spallation using the Ames Vertical Gun Range (AVGR). B. subtilis spores were applied to the surface of a granite target that was impacted from above by an aluminum projectile fired at 5.4 km/s. Granite spall fragments were captured in a foam recovery fixture and then recovered and assayed for shock damage by transmission electron microscopy and for spore survival by viability assays. Peak shock pressure at the impact site was calculated to be 57.1 GPa, though recovered spall fragments were only very lightly shocked at pressures of 5-7 GPa. Spore survival was calculated to be on the order of 10(-5), which is in agreement with results of previous static compressional shock experiments. These results demonstrate that endolithic spores can survive launch by spallation from a hypervelocity impact, which lends further evidence in favor of lithopanspermia theory.

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The Interplanetary Exchange of Photosynthesis

Cited by 48 publications

References 71 publications

Planetary targets in the search for extrasolar oxygenic photosynthesis

Planetary targets in the search for extrasolar oxygenic photosynthesis

Whole Lichen Thalli Survive Exposure to Space Conditions: Results of Lithopanspermia Experiment withAspicilia fruticulosa

Bacterial Spores in Granite Survive Hypervelocity Launch by Spallation: Implications for Lithopanspermia

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