Decomposition - wikipedia Decomposition For other uses, see Decomposition ( disambiguation ). Stages of death 1. Pallor mortis 2. Algor mortis 3. Rigor mortis 4. Livor mortis 5. Putrefaction 6. Decomposition 7. Skeletonization Decomposing fallen nurse log in a forest Decomposition is the process by which organic substances are broken down into simpler matter. The process is a part of nutrient cycle and is essential for recycling the finite matter that occupies physical space in the biosphere. Bodies of living organisms begin to decompose shortly after death. Animals, such as worms, also help decompose the organic materials. Organisms that do this are known as decomposers. Although no two organisms decompose in the same way, they all undergo the same sequential stages of decomposition. The science which studies decomposition is generally referred to as taphonomy from the Greek word taphos, meaning tomb. One can differentiate abiotic from biotic decomposition ( biodegradation ). The former means `` degradation of a substance by chemical or physical processes, e.g., hydrolysis. The latter means `` the metabolic breakdown of materials into simpler components by living organisms '', typically by microorganisms. Contents 1 Animal decomposition 1.1 Stages of decomposition 1.1. 1 Fresh 1.1. 2 Bloat 1.1. 3 Active decay 1.1. 4 Advanced decay 1.1. 5 Dry / remains 2 Plant decomposition 3 Food decomposition 4 Importance to forensics 5 Factors affecting decomposition 5.1 Exposure to the elements 5.2 Anaerobic vs Aerobic 5.3 Artificial preservation 5.4 Environmental preservation 6 See also 7 References 8 External links Animal decomposition Ants eating a dead snake Decomposition begins at the moment of death, caused by two factors : 1. ) autolysis, the breaking down of tissues by the body 's own internal chemicals and enzymes, and 2. ) putrefaction, the breakdown of tissues by bacteria. These processes release compounds such as cadaverine and putrescine, that are the chief source of the unmistakably putrid odor of decaying animal tissue. Prime 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, the flesh - flies ( Sarcophagidae ) and blow - flies ( Calliphoridae ), such as the green - bottle fly seen in the summer. In North America, the most important non-insect animals that are typically involved in the process include mammal and bird scavengers, such as coyotes, dogs, wolves, foxes, rats, crows and vultures. Some of these scavengers also remove and scatter bones, which they ingest at a later time. Aquatic and marine environments have break - down agents that include bacteria, fish, crustaceans, fly larvae and other carrion scavengers. 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. The general stages of decomposition are coupled with two stages of chemical decomposition : autolysis and putrefaction. These two stages contribute to the chemical process of decomposition, which breaks down the main components of the body. Fresh Among those animals that have a heart, the `` fresh '' stage begins immediately after the heart stops beating. From the moment of death, the body begins cooling or warming to match the temperature of the ambient environment, during a stage called algor mortis. Shortly after death, within three to six hours, the muscular tissues become rigid and incapable of relaxing, during a stage called rigor mortis. Since blood is no longer being pumped through the body, gravity causes it to drain to the dependent portions of the body, creating an overall bluish - purple discolouration termed livor mortis or, more commonly, lividity. Once the heart stops, the blood can no longer supply oxygen or remove carbon dioxide from the tissues. The resulting decrease in pH and other chemical changes cause cells to lose their structural integrity, bringing about the release of cellular enzymes capable of initiating the breakdown of surrounding cells and tissues. This process is known as autolysis. Visible changes caused by decomposition are limited during the fresh stage, although autolysis may cause blisters to appear at the surface of the skin. The small amount of oxygen remaining in the body is quickly depleted by cellular metabolism and aerobic microbes naturally present in respiratory and gastrointestinal tracts, creating an ideal environment for the proliferation of anaerobic organisms. These multiply, consuming the body 's carbohydrates, lipids, and proteins, to produce a variety of substances including propionic acid, lactic acid, methane, hydrogen sulfide, and ammonia. The process of microbial proliferation within a body is referred to as putrefaction and leads to the second stage of decomposition, known as bloat. Blowflies and flesh flies are the first carrion insects to arrive, and they seek a suitable oviposition site. Bloat The bloat stage provides the first clear visual sign that microbial proliferation is underway. In this stage, anaerobic metabolism takes place, leading to the accumulation of gases, such as hydrogen sulfide, carbon dioxide, methane, and nitrogen. The accumulation of gases within the bodily cavity causes the distention of the abdomen and gives a cadaver its overall bloated appearance. The gases produced also cause natural liquids and liquefying tissues to become frothy. As the pressure of the gases within the body increases, fluids are forced to escape from natural orifices, such as the nose, mouth, and anus, and enter the surrounding environment. The buildup of pressure combined with the loss of integrity of the skin may also cause the body to rupture. Intestinal anaerobic bacteria transform haemoglobin into sulfhemoglobin and other colored pigments. The associated gases which accumulate within the body at this time aid in the transport of sulfhemoglobin throughout the body via the circulatory and lymphatic systems, giving the body an overall marbled appearance. If insects have access, maggots hatch and begin to feed on the body 's tissues. Maggot activity, typically confined to natural orifices, and masses under the skin, causes the skin to slip, and hair to detach from the skin. Maggot feeding, and the accumulation of gases within the body, eventually leads to post-mortem skin ruptures which will then further allow purging of gases and fluids into the surrounding environment. Ruptures in the skin allow oxygen to re-enter the body and provide more surface area for the development of fly larvae and the activity of aerobic microorganisms. The purging of gases and fluids results in the strong distinctive odors associated with decay. Active decay Active decay is characterized by the period of greatest mass loss. This loss occurs as a result of both the voracious feeding of maggots and the purging of decomposition fluids into the surrounding environment. The purged fluids accumulate around the body and create a cadaver decomposition island ( CDI ). Liquefaction of tissues and disintegration become apparent during this time and strong odors persist. The end of active decay is signaled by the migration of maggots away from the body to pupate. Advanced decay Decomposition is largely inhibited during advanced decay due to the loss of readily available cadaveric material. Insect activity is also reduced during this stage. When the carcass is located on soil, the area surrounding it will show evidence of vegetation death. The CDI surrounding the carcass will display an increase in soil carbon and nutrients, such as phosphorus, potassium, calcium, and magnesium ; changes in pH ; and a significant increase in soil nitrogen. Dry / remains During the dry / remains stage, the resurgence of plant growth around the CDI may occur and is a sign that the nutrients present in the surrounding soil have not yet returned to their normal levels. All that remains of the cadaver at this stage is dry skin, cartilage, and bones, which will become dry and bleached if exposed to the elements. If all soft tissue is removed from the cadaver, it is referred to as completely skeletonized, but if only portions of the bones are exposed, it is referred to as partially skeletonised. Pig carcass in the different stages of decomposition : Fresh > Bloat > Active decay > Advanced decay > Dry remains Plant decomposition See also : Composting, Anaerobic digestion, and Fungal extracellular enzyme activity A decaying peach over a period of six days. Each frame is approximately 12 hours apart, as the fruit shrivels and becomes covered with mold. Decomposition of plant matter occurs in many stages. It begins with leaching by water ; the most easily lost and soluble carbon compounds are liberated in this process. Another early process is physical breakup or fragmentation of the plant material into smaller bits which have greater surface area for microbial colonization and attack. In smaller dead plants, this process is largely carried out by the soil invertebrate fauna, whereas in the larger plants, primarily parasitic life - forms such as insects and fungi play a major breakdown role and are not assisted by numerous detritivore species. Following this, the plant detritus ( consisting of cellulose, hemicellulose, microbial products, and lignin ) undergoes chemical alteration by microbes. Different types of compounds decompose at different rates. This is dependent on their chemical structure. For instance, lignin is a component of wood, which is relatively resistant to decomposition and can in fact only be decomposed by certain fungi, such as the black - rot fungi. Wood decomposition is a complex process involving fungi which transport nutrients to the nutritionally scarce wood from outside environment. Because of this nutritional enrichment the fauna of saproxylic insects may develop and in turn affect dead wood, contributing to wood decomposition and nutrient cycling in the forest floor. Lignin is one such remaining product of decomposing plants with a very complex chemical structure causing the rate of microbial breakdown to slow. Warmth determines the speed of plant decay, with the rate of decay increasing as heat increases, i.e. a plant in a warm environment will decay over a shorter period of time. In most grassland ecosystems, natural damage from fire, insects that feed on decaying matter, termites, grazing mammals, and the physical movement of animals through the grass are the primary agents of breakdown and nutrient cycling, while bacteria and fungi play the main roles in further decomposition. The chemical aspects of plant decomposition always involve the release of carbon dioxide. Food decomposition Main article : Meat spoilage This section needs expansion with : information from the main article. You can help by adding to it. ( July 2010 ) The decomposition of food, either plant or animal, called spoilage in this context, is an important field of study within food science. Food decomposition can be slowed down by conservation. The spoilage of meat occurs, if the meat is untreated, in a matter of hours or days and results in the meat becoming unappetizing, poisonous or infectious. Spoilage is caused by the practically unavoidable infection and subsequent decomposition of meat by bacteria and fungi, which are borne by the animal itself, by the people handling the meat, and by their implements. Meat can be kept edible for a much longer time -- though not indefinitely -- if proper hygiene is observed during production and processing, and if appropriate food safety, food preservation and food storage procedures are applied. Spoilage of food is attributed to contamination from microorganisms such as bacteria, molds, and yeasts, along with natural decay of the food. These decomposition bacteria reproduce at rapid rates under conditions or moisture and preferred temperatures. When the proper conditions are lacking the bacteria may form spores which lurk until suitable conditions arise to continue reproduction. Importance to forensics Further information : Forensic entomological decomposition Various sciences study the decomposition of bodies under the general rubric of forensics because the usual motive for such studies is to determine the time and cause of death for legal purposes : Forensic taphonomy specifically studies the processes of decomposition in order to apply the biological and chemical principles to forensic cases in order to determine post-mortem interval ( PMI ), post-burial interval as well as to locate clandestine graves. Forensic pathology studies the clues to the cause of death found in the corpse as a medical phenomenon. Forensic entomology studies the insects and other vermin found in corpses ; the sequence in which they appear, the kinds of insects, and where they are found in their life cycle are clues that can shed light on the time of death, the length of a corpse 's exposure, and whether the corpse was moved. Forensic anthropology is the medico - legal branch of physical anthropology that studies skeletons and human remains, usually to seek clues as to the identity, age, sex, height and ethnicity of their former owner. The University of Tennessee Anthropological Research Facility ( better known as the Body Farm ) in Knoxville, Tennessee has a number of bodies laid out in various situations in a fenced - in plot near the medical center. Scientists at the Body Farm study how the human body decays in various circumstances to gain a better understanding of decomposition. Factors affecting decomposition Further information : Environmental effects on forensic entomology This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( November 2013 ) Exposure to the elements A dead body that has been exposed to the open elements, such as water and air, will decompose more quickly and attract much more insect activity than a body that is buried or confined in special protective gear or artifacts. This is due, in part, to the limited number of insects that can penetrate a coffin and the lower temperatures under soil. The rate and manner of decomposition in an animal body is strongly affected by several factors. In roughly descending degrees of importance, they are : Temperature ; The availability of oxygen ; Prior embalming ; Cause of death ; Burial, depth of burial, and soil type ; Access by scavengers ; Trauma, including wounds and crushing blows ; Humidity, or wetness ; Rainfall ; Body size and weight ; Clothing ; The surface on which the body rests ; Foods / objects inside the specimen 's digestive tract ( bacon compared to lettuce ). The speed at which decomposition occurs varies greatly. Factors such as temperature, humidity, and the season of death all determine how fast a fresh body will skeletonize or mummify. A basic guide for the effect of environment on decomposition is given as Casper 's Law ( or 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. Ultimately, the rate of bacterial decomposition acting on the tissue will depend upon the temperature of the surroundings. Colder temperatures decrease the rate of decomposition while warmer temperatures increase it. A dry body will not decompose efficiently. Moisture helps the growth of microorganisms that decompose the organic matter, but too much moisture could lead to anaerobic conditions slowing down the decomposition process. The most important variable is a body 's accessibility to insects, particularly flies. On the surface in tropical areas, invertebrates alone can easily reduce a fully fleshed corpse to clean bones in under two weeks. The skeleton itself is not permanent ; acids in soils can reduce it to unrecognizable components. This is one reason given for the lack of human remains found in the wreckage of the Titanic, even in parts of the ship considered inaccessible to scavengers. Freshly skeletonized bone is often called `` green '' bone and has a characteristic greasy feel. Under certain conditions ( normally cool, damp soil ), bodies may undergo saponification and develop a waxy substance called adipocere, caused by the action of soil chemicals on the body 's proteins and fats. The formation of adipocere slows decomposition by inhibiting the bacteria that cause putrefaction. In extremely dry or cold conditions, the normal process of decomposition is halted -- by either lack of moisture or temperature controls on bacterial and enzymatic action -- causing the body to be preserved as a mummy. Frozen mummies commonly restart the decomposition process when thawed ( see Ötzi the Iceman ), whilst heat - desiccated mummies remain so unless exposed to moisture. The bodies of newborns who never ingested food are an important exception to the normal process of decomposition. They lack the internal microbial flora that produce much of decomposition and quite commonly mummify if kept in even moderately dry conditions. Anaerobic vs aerobic Aerobic decomposition takes place in the presence of oxygen. This is most common to occur in nature. Living organisms that use oxygen to survive feed on the body. Anaerobic decomposition takes place in the absence of oxygen. This could be place where the body is buried in organic material and oxygen can not reach it. This process of putrefaction has a bad odor accompanied by it due to the hydrogen sulfide and organic matter containing sulfur. Artificial preservation Embalming is the practice of delaying decomposition of human and animal remains. Embalming slows decomposition somewhat, but does not forestall it indefinitely. Embalmers typically pay great attention to parts of the body seen by mourners, such as the face and hands. The chemicals used in 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 can not act as a nutrient source for subsequent bacterial infections. In sufficiently dry environments, an embalmed body may end up mummified and it is not uncommon for bodies to remain preserved to a viewable extent after decades. Notable viewable embalmed bodies include those of : Eva Perón of Argentina, whose body was injected with paraffin was kept perfectly preserved for many years, and still is as far as is known ( her body is no longer on public display ). Vladimir Lenin of the Soviet Union, whose body was kept submerged in a special tank of fluid for decades and is on public display in Lenin 's Mausoleum. Other Communist leaders with pronounced cults of personality such as Mao Zedong, Kim Il - sung, Ho Chi Minh, Kim Jong - il and most recently Hugo Chávez have also had their cadavers preserved in the fashion of Lenin 's preservation and are now displayed in their respective mausoleums. Pope John XXIII, whose preserved body can be viewed in St. Peter 's Basilica. Padre Pio, whose body was injected with formalin prior to burial in a dry vault from which he was later removed and placed on public display at the San Giovanni Rotondo. Environmental preservation A body buried in a sufficiently dry environment may be well preserved for decades. This was observed in the case for murdered civil rights activist Medgar Evers, who was found to be almost perfectly preserved over 30 years after his death, permitting an accurate autopsy when the case of his murder was re-opened in the 1990s. Bodies submerged in a peat bog may become naturally `` embalmed '', arresting decomposition and resulting in a preserved specimen known as a bog body. The time for an embalmed body to be reduced to a skeleton varies greatly. Even when a body is decomposed, embalming treatment can still be achieved ( the arterial system decays more slowly ) but would not restore a natural appearance without extensive reconstruction and cosmetic work, and is largely used to control the foul odors due to decomposition. An animal can be preserved almost perfectly, for millions of years in a resin such as amber. There are some examples where bodies have been inexplicably preserved ( with no human intervention ) for decades or centuries and appear almost the same as when they died. In some religious groups, this is known as incorruptibility. It is not known whether or for how long a body can stay free of decay without artificial preservation. See also Cadaverine Microbiology of decomposition Putrescine Staling Humus Leachate Peat ( turf ) References Jump up ^ Water Quality Vocabulary. IShaO 6107 - 6 : 1994. Jump up ^ `` Biotic decomposition ''. Water Words Dictionary ( WWD ). Jump up ^ González Medina A, González Herrera L, Perotti MA, Jiménez Ríos G ( 2013 ). `` Occurrence of Poecilochirus austroasiaticus ( Acari : Parasitidae ) in forensic autopsies and its application on postmortem interval estimation ''. Exp. Appl. Acarol. 59 ( 3 ) : 297 -- 305. doi : 10.1007 / s10493 - 012 - 9606 - 1. Jump up ^ 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. Jump up ^ González Medina A, Soriano Hernando Ó, Jiménez Ríos G ( 2015 ). `` The Use of the Developmental Rate of the Aquatic Midge Chironomus riparius ( Diptera, Chironomidae ) in the Assessment of the Postsubmersion Interval ''. J. Forensic. Sci. 60 ( 3 ) : 822 -- 826. doi : 10.1111 / 1556 - 4029.12707. ^ Jump up to : Payne, J.A. ( 1965 ). `` A summer carrion study of the baby pig sus scrofa Linnaeus ''. Ecology. 46 ( 5 ) : 592 -- 602. doi : 10.2307 / 1934999. Jump up ^ 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. ^ Jump up to : 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. CS1 maint : Multiple names : authors list ( link ) Jump up ^ Knight, Bernard ( 1991 ). Forensic pathology. Oxford University Press. ISBN 0 - 19 - 520903 - 6. ^ Jump up to : Carter D.O., Yellowlees ; D., Tibbett M. ( 2007 ). `` Cadaver decomposition in terrestrial ecosystems ''. Naturwissenschaften. 94 ( 1 ) : 12 -- 24. PMID 17091303. doi : 10.1007 / s00114 - 006 - 0159 - 1. ^ Jump up to : 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. Jump up ^ 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. Jump up ^ Vass A.A. ; Bass W.M. ; volt 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. Jump up ^ 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. Jump up ^ Filipiak, Michał ; Sobczyk, Łukasz ; Weiner, January ( 2016 - 04 - 09 ). `` Fungal Transformation of Tree Stumps into a Suitable Resource for Xylophagous Beetles via Changes in Elemental Ratios ''. Insects. 7 ( 2 ) : 13. doi : 10.3390 / insects7020013. ^ Jump up to : Filipiak, Michał ; Weiner, January ( 2016 - 09 - 01 ). `` Nutritional dynamics during the development of xylophagous beetles related to changes in the stoichiometry of 11 elements ''. Physiological Entomology : n / a -- n / a. ISSN 1365 - 3032. doi : 10.1111 / phen. 12168. ^ Jump up to : Anita, Tull ( 1997 ). Food and nutrition. Oxford University Press. pp. 154, 155. ISBN 978 - 0 - 19 - 832766 - 0. Jump up ^ Smith, KGV. ( 1987 ). A Manual of Forensic Entomology. Cornell Univ. Pr. p. 464. ISBN 0 - 8014 - 1927 - 1. Jump up ^ Kulshrestha P, Satpathy DK ( 2001 ). `` Use of beetles in forensic entomology ''. Forensic Sci. Int. 120 ( 1 -- 2 ) : 15 -- 17. PMID 11457603. doi : 10.1016 / S0379 - 0738 ( 01 ) 00410 - 8. Jump up ^ Schmitt, A. ; Cunha, E. ; Pinheiro, J. ( 2006 ). Forensic Anthropology and Medicine : Complementary Sciences From Recovery to Cause of Death. Humana Press. p. 464. ISBN 1 - 58829 - 824 - 8. Jump up ^ Haglund, WD. ; Sorg, MH. ( 1996 ). Forensic Taphonomy : The Postmortem Fate of Human Remains. CRC Press. p. 636. ISBN 0 - 8493 - 9434 - 1. ^ Jump up to : `` Chapter 1, The Decomposition Process Earth - Kind ® Landscaping ''. aggie-horticulture.tamu.edu. Retrieved 2017 - 02 - 05. Jump up ^ Quigley, C. ( 1998 ). Modern Mummies : The Preservation of the Human Body in the Twentieth Century. McFarland. pp. 213 -- 214. ISBN 0 - 7864 - 0492 - 2. Jump up ^ Clark, Josh. `` How can a corpse be incorruptible ? ''. HowStuffWorks. External links Look up decomposition, spoilage, or perishable in Wiktionary, the free dictionary. Media related to Decomposition at Wikimedia Commons 1Lecture.com -- Food decomposition ( a Flash animation ) Preceded by Death Stages of human development Decomposition Succeeded by Skeletonization Ecology : Modelling ecosystems : Trophic components General Abiotic component Abiotic stress Behaviour Biogeochemical cycle Biomass Biotic component Biotic stress Carrying capacity Competition Ecosystem Ecosystem ecology Ecosystem model Keystone species List of feeding behaviours Metabolic theory of ecology Productivity Resource Producers Autotrophs Chemosynthesis Chemotrophs Foundation species Mixotrophs Myco - heterotrophy Mycotroph Organotrophs Photoheterotrophs Photosynthesis Photosynthetic efficiency Phototrophs Primary nutritional groups Primary production Consumers Apex predator Bacterivore Carnivores Chemoorganotroph Foraging Generalist and specialist species Intraguild predation Herbivores Heterotroph Heterotrophic nutrition Insectivore Mesopredators Mesopredator release hypothesis Omnivores Optimal foraging theory Predation Prey switching Decomposers Chemoorganoheterotrophy Decomposition Detritivores Detritus Microorganisms Archaea Bacteriophage Environmental microbiology Lithoautotroph Lithotrophy Microbial cooperation Microbial ecology Microbial food web Microbial intelligence Microbial loop Microbial mat Microbial metabolism Phage ecology Food webs Biomagnification Ecological efficiency Ecological pyramid Energy flow Food chain Trophic level Example webs Cold seeps Hydrothermal vents Intertidal Kelp forests Lakes North Pacific Subtropical Gyre Rivers San Francisco Estuary Soil Tide pool Processes Ascendency Bioaccumulation Cascade effect Climax community Competitive exclusion principle Consumer - 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Question: where do materials that decay or decompose come from
Answer: organic substances