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| A human skull, widely used as a symbol of death and decomposition [1] |
Yes, I'm guessing the subject of decomposition may make some people cringe. But I'm a weirdo; I find every facet of nature, from dust to dust absolutely fascinating. There is such beauty in the balance of nature, even when accompanied by noxious odours. But the thing is, the very fact we find the odour of decomposition revolting is in itself a beautiful thing, for were it not so, we probably wouldn't be here.
For everything a reason; and yes, even those mosquitoes I detest are not without purpose. And though the apparent purpose of some things may be purely aesthetic, they are nonetheless representative pigments in nature's vast and beautiful canvass.
To my mind, it is often through gaining a better understanding of why things are as they are that we come to view even the less pleasant aspects of life (and death) as necessary, balanced and ... dare I say, beautiful? Yes, when we understand the why, even maggots can gain our appreciation. But as I said before, I'm a weirdo.
My only fear of death stems not from unsettling thoughts about decomposition, rather from the equally morbid idea of not actually being dead, but being pronounced dead. And perhaps my fears have been allayed somewhat through learning about the decomposition process, and knowing that, well, if its happening then I am most certainly deceased. Of course this does nothing to allay my fears of being mistakenly buried alive, but I guess for that one I will have to put my trust in the decision making abilities of modern medicine. Still, perhaps a bell attached to a string is not such a bad idea after all. And yes, in case it isn't already blatantly obvious, I did read far too much Poe in my formative years.
Death is the
termination of all biological functions that sustain a living organism.
Bodies of living organisms begin to decompose
shortly after death. [1]
*Decomposition: A process by which organic matter is broken down
into simpler forms of matter, accompanied by a strong, unpleasant odor. [1][2]
*Not all materials need to be
decomposed fully. One example is coal, a fossil fuel
formed over vast tracts of time in swamp ecosystems. [1]
Decomposition is caused by two factors: [2]
Autolysis: The breaking down of tissues by the body's own internal chemicals and enzymes.
Putrefaction: The breakdown of tissues by microbes.
The gases released by these processes are the main source of the putrid odor accompanying decaying animal tissue. [2]
Primary decomposers are bacteria or fungi, though larger scavengers also play an important role in decomposition if the body is accessible to insects, mites and other animals. The most important arthropods that are involved in the process include carrion beetles, mites,[3*] flesh-flies and blow-flies. [2]
Autolysis: The breaking down of tissues by the body's own internal chemicals and enzymes.
Putrefaction: The breakdown of tissues by microbes.
The gases released by these processes are the main source of the putrid odor accompanying decaying animal tissue. [2]
Primary decomposers are bacteria or fungi, though larger scavengers also play an important role in decomposition if the body is accessible to insects, mites and other animals. The most important arthropods that are involved in the process include carrion beetles, mites,[3*] flesh-flies and blow-flies. [2]
Stages of decomposition
Five general stages are used to describe the process of decomposition in
vertebrate animals: fresh, bloat, active decay, advanced decay, and dry/remains.[4*] The general stages of decomposition are coupled with the aforementioned two stages of
chemical decomposition: autolysis and putrefaction. [5*]
Fresh (Decomposition starts from within)
Pallor mortis: Paleness which happens in the 15–120 minutes after death.[1]
Livor mortis (lividity): When the heart stops beating, blood begins to pool creating, “an overall bluish-purple discoloration."[6*][7*]
Rigor mortis: Within 3 to 6 hours after death, muscle tissue becomes rigid.[6*][7*]
Algor mortis: From the moment of death, the body begins to lose heat.[6*][7*]
Autolysis:[6*][8*][18] When respiration ceases, acidic CO2 accumulates in cells. This causes sacs inside the cells to rupture and release enzymes, which break down cells and tissues. This process can be seen as blisters on the skin.
Purification:[6*][8*][18] Aerobic microbes residing in the respiratory and GI tracts, deplete the remaining oxygen. The environment is now primed for the invasion of anaerobic microbes. These microbes consume the slurry of carbohydrates, lipids and proteins, producing propionic acid, lactic acid, methane, hydrogen sulfide and ammonia in the process.
Bloat
 |
| Blowfly and fly larvae on 5-day old corpse of South African Porcupine [2] |
Microbial anaerobic metabolism leads to the accumulation of gases like
hydrogen sulfide, carbon dioxide and methane which cause the body cavity to appear
bloated and the liquefied tissue to froth.[7*][9*] The build-up of pressure will now force the release of gases into the
environment.[9*]
The build-up of pressure will also transport the pigmented products of
anaerobic metabolism through the body giving skin a marbled appearance.[10*] (ie: hemoglobin to sulfhemoglobin)
If maggots have access, they will hatch and feed, thus causing skin and
hair to slip and loosen, respectively.[4*][7*] This will cause further release gases and fluids.[6*] Exposure to oxygen will enable larvae to develop.[9*]
 |
| Proposed evolution of microorganisms within the body during decomposition. As oxygen is available at the beginning of decomposition, aerobic microorganisms flourish and quickly deplete the oxygen. Anaerobic bacteria can then proliferate in the body. Later in the decomposition process, fungi and bacteria from the environment will also become involved in the process.[19] |
Active decay
During this phase, the feeding maggots and beetles will consume any remaining
tissue. [9*] A CDI, or Cadaver Decomposition Island will form around the body from
the accumulation of released fluids.[6*] The end of
this stage is signaled by the migration of maggots away from the body to
pupate.[6*]
Advanced decay
Due to loss of tissue, there is minimal further decomposition during
this stage.[9*]
The CDI surrounding the carcass will display an increase in soil carbon, nitrogen
and nutrients, such as phosphorus, potassium, calcium, and magnesium and changes in
pH.[11*][6*]
Dry/Remains
All that remains of the cadaver at this stage is dry skin, cartilage,
and bones.[4*] Over time the protein in the bone decomposes as well.[18] When all of the soft tissue is removed from the cadaver, it is referred
to as completely skeletonized.[12*]
 |
Pig carcass in the different stages of decomposition: Fresh > Bloat > Active decay > Advanced decay > Dry remains [2]
|
The rate and manner of decomposition in an animal's body is strongly affected by factors like temperature and humidity.[2]
A basic guide for the effect of environment on decomposition is given as
Casper's ratio: if all other factors are equal, then, when there is
free access of air, a body decomposes twice as fast than if immersed in water
and eight times faster than if buried in earth.[2]
Under certain conditions (normally cool, damp soil), the actions of soil chemicals on the body's proteins and fats may cause the formation of a waxy substance called an adipocere. This process slows decomposition by inhibiting the bacteria that
cause putrefaction.[2]
 |
| Dead bodies can be mummified either naturally, as this one from Guanajuato, or by intention, as those in ancient Egypt. [1] |
In extremely dry or cold conditions, the normal process of decomposition is halted causing the body to be preserved as a mummy. Frozen mummies commonly restart the decomposition process when thawed, whilst heat-desiccated mummies remain so unless exposed to moisture.[2]
Bodies submerged in a peat bog may become naturally "embalmed", arresting decomposition and resulting in a preserved specimen known as a bog body.[2]
An animal can be preserved almost perfectly, for millions of years in a
resin such as amber.[2]
The chemicals used in the practice of embalming repel most insects, and slow down bacterial putrefaction by either killing existing bacteria in or on the body themselves or by "fixing" cellular proteins, which means that they cannot act as a nutrient source for subsequent bacterial infections.[2]
The chemicals used in the practice of embalming repel most insects, and slow down bacterial putrefaction by either killing existing bacteria in or on the body themselves or by "fixing" cellular proteins, which means that they cannot act as a nutrient source for subsequent bacterial infections.[2]
The Indescribable Scent Of Dead Bodies: Researchers Identify Unique Gases Emitted By Decomposing Human Flesh / Medical Daily / September 23, 2015
[1] http://en.wikipedia.org/wiki/Death
[2] http://en.wikipedia.org/wiki/Decomposition
[3] Braig, Henk R.; Perotti, M. Alejandra (2009). "Carcases and mites". Experimental and Applied Acarology 49 (1–2): 45–84. doi:10.1007/s10493-009-9287-6.
[4] Payne, J.A. (1965). "A summer carrion study of the baby pig sus scrofa Linnaeus". Ecology 46 (5): 592–602. doi:10.2307/1934999.
[5] Forbes, S.L. (2008). "Decomposition Chemistry in a Burial Environment". In M. Tibbett, D.O. Carter. Soil Analysis in Forensic Taphonomy. CRC Press. pp. 203–223. ISBN 1-4200-6991-8.
[6] Carter D.O., Yellowlees, D., Tibbett M. (2007). "Cadaver decomposition in terrestrial ecosystems". Naturwissenschaften 94 (1): 12–24. doi:10.1007/s00114-006-0159-1. PMID 17091303.
[7] Janaway R.C., Percival S.L., Wilson A.S. (2009). "Decomposition of Human Remains". In Percival, S.L. Microbiology and Aging. Springer Science + Business. pp. 13–334. ISBN 1-58829-640-7.
[8*] Knight, Bernard (1991). Forensic pathology. Oxford University Press. ISBN 0-19-520903-6.
[9] Carter D.O., Tibbett M. (2008). "Cadaver Decomposition and Soil: Processes". In M. Tibbett, D.O. Carter. Soil Analysis in Forensic Taphonomy. CRC Press. pp. 29–51. ISBN 1-4200-6991-8.
[10] Pinheiro, J. (2006). "Decay Process of a Cadaver". In A. Schmidt, E. Cumha, J. Pinheiro. Forensic Anthropology and Medicine. Humana Press. pp. 85–116. ISBN 1-58829-824-8.
[11] Vass A.A., Bass W.M., Wolt J.D., Foss J.E., Ammons J.T. (1992). "Time since death determinations of human cadavers using soil solution". Journal of Forensic Sciences 37 (5): 1236–1253. PMID 1402750.
[12] Dent B.B., Forbes S.L., Stuart B.H. "Review of human decomposition processes in soil". Environmental Geology 45: 576–585. doi:10.1007/s00254-003-0913-z.
[17] Quigley, C. (1998). Modern Mummies: The Preservation of the Human Body in the Twentieth Century. McFarland. pp. 213–214. ISBN 0-7864-0492-2.
[18] https://www.youtube.com/watch?v=Wg2A9iAe25c
[19] http://en.wikipedia.org/wiki/Microbiology_of_decomposition
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"Decomposition00" by Paul venter - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Decomposition00.jpg#mediaviewer/File:Decomposition00.jpg
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"Decomposition stages" by Hbreton19 - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Decomposition_stages.jpg#mediaviewer/File:Decomposition_stages.jpg
"Placid death" by Tomas Castelazo - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Placid_death.JPG#mediaviewer/File:Placid_death.JPG
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