decay of organic matter


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decay of organic matter

or

putrefaction,

process whereby heterotrophic organisms, including some bacteria, fungi, saprophytic plants, and lower animals, utilize the remains of once-living tissue as a source of nutrition. The polysaccharides, lipids, nucleic acids, and proteins of dead tissue are broken down into smaller organic molecules, often by enzymes that are secreted into the external environment by the bacteria and fungi that are involved; the breakdown products are then readily absorbed by the heterotrophs and are used both as a source of building blocks for the synthesis of their own polysaccharides, lipids, nucleic acids, and proteins, and as a source of chemical energy, obtained either by fermentationfermentation,
process by which the living cell is able to obtain energy through the breakdown of glucose and other simple sugar molecules without requiring oxygen. Fermentation is achieved by somewhat different chemical sequences in different species of organisms.
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 (in an anaerobic environment) or respirationrespiration,
process by which an organism exchanges gases with its environment. The term now refers to the overall process by which oxygen is abstracted from air and is transported to the cells for the oxidation of organic molecules while carbon dioxide (CO2
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 (in the presence of oxygen). Often during the process of putrefaction, trace elements and nitrogen are released into the environment in forms suitable for uptake by higher plants; this is the basis for the use of decayed organic matter as fertilizer. The disagreeable odor produced as putrefaction takes place is caused by the formation of certain gases, including ammonia and hydrogen sulfide, and certain volatile amines, including putrescine and cadaverine, two products of the breakdown of protein by microorganisms.
References in periodicals archive ?
Rates of decay of organic matter in wetland environments are strongly influenced by the species of emergent vascular plants and the chemical composition of plant tissues (Polunin 1984; Webster and Benfield 1986).
In natural ecosystems, it is the recycling of nutrients through decay of organic matter that primarily defines nutrient availability and productivity of the system.