Planetary Resources and Astroecology. Planetary Microcosm Models of Asteroid and Meteorite Interiors: Electrolyte Solutions and Microbial Growth— Implications for Space Populations and Panspermia

Abstract

Planetary microcosms were constructed using extracts from meteorites that simulate solutions in the pores of carbonaceous chondrites. The microcosms were found to support the growth of complex algal and microbial populations. Such astroecology experiments demonstrate how a diverse ecosystem could exist in fluids within asteroids, and in meteorites that land on aqueous planets. The microcosm solutions were obtained by extracting nutrient electrolytes under natural conditions from powders of the Allende (CV3) and Murchison (CM2) meteorites at low (0.02 g/ml) and high (10.0 g/ml) solid/solution ratios. The latter solutions contain > 3 mol/L electrolytes and about 10 g/L organics, that simulate natural fluids in asteroids during aqueous alteration and in the pores of meteorites, which can help prebiotic synthesis and the survival of early microorganisms. These solutions and wet solids were in fact found to support complex self-sustaining microbial communities with populations of 4 x 10(5) algae and 6 x 10(6) bacteria and fungi for long periods (> 8 months). The results show that planetary microcosms based on meteorites can: assay the fertilities of planetary materials; identify space bioresources; target astrobiology exploration; and model past and future space-based ecosystems. The results show that bioresources in the carbonaceous asteroids can sustain a biomass of 10(18) kg, comprising 10(32) microorganisms and a human population of 10(14). The results also suggest that protoplanetary nebulae can support and disperse microorganisms and can be therefore effective environments for natural and directed panspermia.

Astroecology, cosmo-ecology, and the future of life

“…4) [8,9,14]. We also found that brine shrimp eggs can uptake meteorite materials and can hatch in meteorite extracts, which shows that the extracts are not significantly toxic.…”

“…The biomass that can be constructed from element x in a resource material is given by Equation (3) [8,9].…”

“…This gives the potential yield of biomass from a unit mass (kg) of resource materials [Equation (3) and Tab. 1], with bioavailable P and N as the limiting elements [8,9]. For example, eight different carbonaceous chondrite meteorites contained an average bioavailable phosphate content of c x,resource = 0.0012 g/kg meteorite solids [14].…”

“…Tests of meteorites showed that microorganisms can be sustained by the nutrients in these asteroid solutions [8,9].…”

Biological evidence against the panspermia theory

“…This suggestion has been criticised (Gualtieri, 1977). Planetary microcosms models of asteroids and meteorites also suggest that protoplanetary nebulae might support and disperse micro-organisms (Mautner, 2002). Wickramasinghe (2004) has been one of the great supporters of the panspermia theory and has gathered considerable evidence in its favour (Wallis et al, 1992;Sommer and Wickramasinghe, 2005).…”