Re: If a dead body were floating in space, would it decompose?

Bacteria and fungi carry out the majority biological decomposition, or "recycling" of organic molecules in dead organisms. Humans have a dense microbial flora living on the skin, and in the gastrointestinal and genitourinay systems. After death these organisms have free reign as host defenses are no longer present to keep them in their place (a veritable microbial smorgasbord..). However, their growth and metabolism require certain conditions.

1. Oxygen?: Aerobes, microbes requiring oxygen, cannot grow and divide without it. However, after death, the host is anoxic due to the lack of O2 transport in the blood. No O2 in space either..
2. No oxygen?: Anaerobes represent the majority of organisms that colonize host environments. They cannot grow in the presence of O2. These guys carry out most biodecomposition reactions in normal environments.
3. "Food source": Microbes need certain things to grow, a source of carbon (sugars, e.g.), nitrogen (found in proteins), and vitamins and minerals. Death provides the ultimate organic buffet if you happen to be a bacterium. Host proteins, sugars, fats, vitamins and minerals are suddenly there for the taking..
4. "Growth conditions": All microbes have an ideal temperature for growth - 37°C (98.6°F) is usually optimal for organisms colonizing mammalian intestines. Pressure can also play a role, particularly in the vacuum of space. The vacuum could possibly rupture cell membranes. However, the temperature of space ( close to abolute zero) will keep the body from decomposing once the microbes freeze.

-L. Bry, MadSci Admin