ASTROBIOLOGY Volume 2, Number 1, 2002 © Mary Ann Liebert, Inc. Research Paper Planetary Resources and Astroecology. Planetary Microcosm Models of Asteroid and Meteorite Interiors: Electrolyte Solutions and Microbial Growth— Implications for Space Populations and Panspermia MICHAEL N. MAUTNER 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 aque- ous planets. The microcosm solutions were obtained by extracting nutrient electrolytes un- der natural conditions from powders of the Allende (CV) and Murchison (CM2) meteorites at low (0.02 g/ml) and high (10.0 g/ml) solid/solution ratios. The latter solutions, which sim- ulate natural extractions of asteroids and meteorites by water during aqueous alteration, were found to contain 3 mol/L electrolytes and 1 mol/L organics, concentrated solutions favor- able for prebiotic synthesis. The solutions and wet solids, inoculated with diverse microbial populations from a wetland, were found to support complex self-sustaining microbial com- munities for long periods (8 months), with steady-state populations on the order of 4  10 5 CFU/ml algae and 6  10 6 CFU/ml bacteria and fungi. Planetary microcosm experiments based on meteorite materials can assist in assaying the fertilities of planetary materials and identi- fying space bioresources, targeting astrobiology exploration, modeling past and future space- based ecosystems, and evaluating sustainable populations in the Solar System. The results also suggest that protoplanetary nebulae can be effective nurseries for microorganisms and useful targets for directed panspermia. Key Words: Astroecology—Asteroids—Comets—Me- teorites—Microorganisms—Panspermia. Astrobiology 2, xxx–xxx. 59 INTRODUCTION C ARBONACEOUS OBJECTS in the Solar System in- clude meteorites, asteroids, comets, and inter- planetary dust particles (IDPs). Under aqueous conditions, internal solutions that form in these ob- jects may originate and sustain microbial life. To assess these roles requires an understanding of the chemistry and biology of these materials. The pre- sent series of experiments applies microcosm sim- ulations, based on actual extraterrestrial materials in meteorites, to elucidate these properties (Maut- Soil, Plant and Ecological Sciences Division, Lincoln University, Lincoln, New Zealand and Department of Chem- istry, University of Canterbury, Christchurch, New Zealand.