Body decays in a microbe-free environment?

[drcathyc]

Hi! I'm a science fiction writer and need to know if a body would decay in a microbe-free environment. I have a killer running loose on a space station (far future). He kills and leaves a body in a secluded area. After a couple months, would the body have decayed? To what extent? Thanks for the help.

 

[vadslram]

Entirely depends on how microbe free. The body has a lot of wee beasties in it at any time so decomp doesn't really depend on external flora.
If the environment is hostile enough to microbial life the body will last a LOOOONNGG time. There are documented cases of natural mummies in the Andes where it is very cold and dry. And there was that ice mummy they found also.

 

[Decimator]

Your gut flora is perfectly happy to decompose you. The victim would start to stink just like normal, but there wouldn't be any flies or scavengers to speed the actual eating process. So the body would stink worse, and longer.

How squeamish are you? There's a lot of research on this subject for police forensics.

 

[StrayCatalyst]

You carry microbes around with you. Unless the body were sterilized, decomposition wouldn't need to wait for external sources of microbes.

You're also carrying around a few litres of acid in your stomach, as well... at a ph of 1.5-3.5, it will start digesting its way through the stomach promptly.

 

[SteamKing]

Ancient Egyptians were very careful to dry the body inside and out, which inhibited microbe activity. In addition, the internal organs were removed during mummification and stored in special jars.

 

[SteamKing]

You carry microbes around with you. Unless the body were sterilized, decomposition wouldn't need to wait for external sources of microbes.

You're also carrying around a few litres of acid in your stomach, as well... at a ph of 1.5-3.5, it will start digesting its way through the stomach promptly.

The capacity of the average human stomach is about one liter. The stomach only releases gastric acid when food enters to be digested. The mixture of partially digested food, containing the gastric acid, then goes to the small intestine for absorption.

The stomach releases HCl partly to sterilize any bacteria swallowed during the meal and also to activate the enzymes which do the bulk of the digestion.

http://en.wikipedia.org/wiki/Stomach

 

[snorkack]

Corpses routinely undergo significant degree of mummification at homes. Stomach microbes do cause a lot of decomposition, but drying competes with them in warm, dry air thanks to central heating.

How dry is the air in the space station?

 

[Chronos]

Biological decomposition would not occur in the absence of microbes. The microbes already present in the human body would happily assume the job in the absence of completion. A human body devoid of microbes and in a sterile environment would mummify due to desiccation. Dying cells would also release metabolites that would degrade tissues, but, are routinely cleansed by a living body. It is an interesting question if the human body could survive without any microbes. They are known to participate in some normal body functions, like digestion, and perhaps other critical functions in ways not yet understood. Given we evolved in a microbe rich environment, we surely have developed certain symbiotic relationships with some of our little bug buddies. Eliminating all of them could have drastic, perhaps even fatal consequences. At best, you would have little protection if exposed to them after a microbe free existence.

 

[snorkack]

Biological decomposition would not occur in the absence of microbes.

As pointed out below, there are other decomposition mechanisms besides microbes.

The microbes already present in the human body would happily assume the job in the absence of completion. A human body devoid of microbes and in a sterile environment would mummify due to desiccation.

Human bodies devoid of microbes are universally found. Placenta successfully blocks all microbes except in case of some serious infections. Children born by caesarean section are devoid of microbes; children born by vagina have small number on microbes on their skin (that came from vagina) but none in their bellies.

A human body can only mummify die to desiccation if the environment, besides being sterile, is also dry! A human body in sterile water or in sterile but moist air obviously cannot mummify. For example children who die in womb and for some reason take time being born will stay sterile - but decompose, in a manner called "maceration".

And the opposite - in dry air, bodies devoid of microbes will readily mummify even if the environment is not sterile. After all, body starts drying from skin. In an adult or an older baby corpse, the belly deep inside would be the last to dry, and meanwhile the gut microbes will start consuming the corpse inside out until they meet the skin that has dried out in the meantime; in a newborn corpse that has not sucked microbes into its belly, bacteria do not easily get into the still wet entrails before they dry up throughout.

It is an interesting question if the human body could survive without any microbes. They are known to participate in some normal body functions, like digestion, and perhaps other critical functions in ways not yet understood. Given we evolved in a microbe rich environment, we surely have developed certain symbiotic relationships with some of our little bug buddies. Eliminating all of them could have drastic, perhaps even fatal consequences. At best, you would have little protection if exposed to them after a microbe free existence.

We know that monkeys can and do survive without any microbes. There is no reason to expect that man could not.

 

[Chronos]

It is true that newborn infants guts are microbe free, especially those born by C-section. Studies show [http://www.cmaj.ca/site/misc/pr/11feb13_pr.xhtml] however, that children born by C section are compromised compared to those birthed naturally. There is also clear evidence [http://www.npr.org/templates/story/story.php?storyId=7039533] microbes play important roles later in life. Studies also show [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3520023/] we share analogous microbiatae with monkeys.

 

[SteamKing]

Corpses routinely undergo significant degree of mummification at homes. Stomach microbes do cause a lot of decomposition, but drying competes with them in warm, dry air thanks to central heating.

How dry is the air in the space station?

According to this:

http://space.stackexchange.com/questions/2539/air-temperature-and-humidity-inside-the-iss

not very dry at all, about 60% RH. If the air gets too dry, the nasal passages get dried out and inflamed.

 

[DHF]

You have a lot of room to play with here being set in a far future on a space station so you can craft an environment to do what you need. if you need the body to forgo decomp then the body could be stashed not only in a sterile room but one that is hostile to microbes. If for example the body was stashed in a room near a reactor where low levels of radiation were present, or if the body were stashed in some manner of clean room with UV lamps then the body would soon be devoid of all living organisms. The body might however suffer burns from exposure, I am not sure on that.

 

[javamann]

Ancient Egyptians were very careful to dry the body inside and out, which inhibited microbe activity. In addition, the internal organs were removed during mummification and stored in special jars.

Canopic jars. q.v.

 

[Nugatory]

Hi! I'm a science fiction writer and need to know if a body would decay in a microbe-free environment. I have a killer running loose on a space station (far future). He kills and leaves a body in a secluded area. After a couple months, would the body have decayed? To what extent? Thanks for the help.

If you can arrange to freeze the body (inhibiting activity of microorganisms and slowing enzymatic processes) and then allow the moisture to sublimate away (dry air will do the trick, but vacuum will work much faster) you should get a pretty convincing mummy.

Think about freeze-dried backpackers' food, freezer-burned meat, and Otzi the iceman, for example.