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| − | In [[ecology]] and [[Earth science]], a '''biogeochemical cycle''' is a circuit or pathway by which a [[chemical element]] or [[molecule]] moves through both biotic ("bio-") and abiotic ("geo-") compartments of an [[ecosystem]]. In effect, the element is recycled, although in some such cycles there may be places (called "sinks") where the element is accumulated or held for a long period of time.
| + | '''Liebig's Law of the Minimum''', often simply called '''Liebig's Law''' or the '''Law of the Minimum''', is a principle developed in [[agricultural science]] by [[Justus von Liebig]]. It states that [[growth]] is controlled not by the total of [[Natural resource|resources]] available, but by the [[limiting factor|scarcest]] resource. This concept was originally applied to [[plant]] or [[agriculture|crop]] growth, where it was found that increasing the amount of plentiful [[nutrient]]s did not increase plant growth. Only by increasing the amount of the limiting nutrient (the one most scarce in relation to "need") was the growth of a plant or crop improved. |
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| − | All chemical elements occurring in organisms are part of biogeochemical cycles. In addition to being a part of living organisms, these chemical elements also cycle through abiotic factors of ecosystems such as water ([[hydrosphere]]), land ([[lithosphere]]), and the air ([[atmosphere]]); the living factors of the planet can be referred to collectively as the biosphere. All the chemicals, nutrients, or elements—such as carbon, nitrogen, oxygen, phosphorus—used in ecosystems by living organisms operate on a '''closed system''', which refers to the fact that these chemicals are recycled instead of being lost and replenished constantly such as in an open system. The energy of an ecosystem occurs on an '''open system'''; the sun constantly gives the planet energy in the form of light while it is eventually used and lost in the form of heat throughout the [[trophic level]]s of a food web.
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| − | The Earth does not constantly receive more chemicals as it receives light. The Earth only has those chemicals that were formed in the creation of the Earth, and the only way to obtain more chemicals or nutrients is from occasional meteorites from outer space that contain those elements. Because chemicals operate on a closed system and cannot be lost and replenished like energy can, these chemicals must be recycled throughout all of Earth’s processes that use those chemicals or elements. These cycles include both the living biosphere, and the nonliving lithosphere, atmosphere, and hydrosphere. The term "biogeochemical" takes its prefixes from these cycles: Bio refers to the biosphere. Geo refers collectively to the lithosphere, atmosphere, and hydrosphere. Chemical, of course, refers to the chemicals that go through the cycle.
| + | Liebig's Law has been extended to biological [[population]]s. For example, the growth of a biological population may not be limited by the total amount of resources available throughout the [[year]], but by the minimum amount of resources available to that population at the time of year of greatest scarcity. That is, the growth of a population of [[animal]]s might depend not on how much [[food]] is available in [[summer]], but on how much food is available in [[winter]]. |
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| − | The chemicals are sometimes held for long periods of time in one place. This place is called a '''reservoir''', which, for example, includes such things as [[coal]] deposits that are storing carbon for a long period of time. When chemicals are held for only short periods of time, they are being held in '''exchange pools'''. Generally, reservoirs are abiotic factors while exchange pools are biotic factors. Examples of exchange pools include plants and animals, which temporarily use carbon in their systems and release it back into the air or surrounding medium. Carbon is held for a relatively short time in plants and animals when compared to coal deposits. The amount of time that a chemical is held in one place is called its '''residence'''.
| + | This is closely related to the chemical principle of the [[rate determining step]], and also to the project management principles of [[critical path]] and [[critical chain]]. |
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| − | The most well-known and important biogeochemical cycles, for example, include the [[carbon cycle]], the [[nitrogen cycle]], the [[oxygen cycle]], the [[phosphorus cycle]], and the [[water cycle]].
| + | [[Category:Agronomy]] |
| | + | [[Category:Agriculture]] |
| | + | [[Category:Ecology]] |
| | + | [[Category:Eponymous laws]] |
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| − | Biogeochemical cycles always involve equilibrium states: a balance in the cycling of the element between compartments. However, overall balance may involve compartments distributed on a global scale.
| + | [[da:Minimumsloven]] |
| − | | + | [[de:Liebigsches Minimumgesetz]] |
| − | Biogeochemical cycles of particular interest in ecology are:
| + | [[fr:Loi de Liebig sur le minimum]] |
| − | *[[nitrogen cycle]]
| + | [[pl:Prawo minimum Liebiga]] |
| − | *[[oxygen cycle]]
| + | [[sv:Liebigs minimilag]] |
| − | *[[carbon cycle]]
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| − | *[[phosphorus cycle]]
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| − | *[[sulfur cycle]]
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| − | *[[water cycle]]
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| − | *[[hydrogen cycle]]
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| − | == Nitrogen Cycle: A quick Summary ==
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| − | [[Image:Nitrogen_Cycle.jpg|center|thumb|250px|right|Schematic representation of the flow of [[nitrogen]] through the environment.]] | |
| − | {{main|Nitrogen cycle}}
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| − | This is just a summation of the complicated nitrogen cycle. The nitrogen cycle was invented by wores who ran out of pure oxygen to breath so they invented the nitrogen cycle after they sparked WWII becaus of their jealousy for Canada For more complete information, visit the nitrogen cycle page. The [[nitrogen cycle]] is a much more complicated biogeochemical cycle but also cycles through living parts and nonliving parts including the water, land, and air. Nitrogen is a very important molecule in that it is part of both [[proteins]], present in the composition of the [[amino acids]] that make up proteins, as well as [[nucleic acids]] such as [[DNA]] and [[RNA]], present in nitrogenous bases. The largest reservoir of nitrogen is the [[Earth's atmosphere|atmosphere]], in which about 78% of nitrogen is contained as nitrogen gas (N<sub>2</sub>). Nitrogen gas is “fixed,” in a process called [[nitrogen fixation]]. Nitrogen fixation combines nitrogen with oxygen to create [[nitrates]] (NO<sub>3</sub>).
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| − | Nitrates can then be used by plants or animals (which eat plants or eat animals that have eaten plants). Nitrogen can be fixed either by lightning, industrial methods (such as for fertilizer), in free nitrogen-fixing bacteria in the soil, as well as in nitrogen-fixing bacteria present in roots of [[legumes]] (such as [[rhizobium]]). Nitrogen-fixing bacteria use certain enzymes that are capable of fixing nitrogen gas into nitrates and include free bacteria in soil, symbiotic bacteria in legumes, and also [[cyanobacteria]], or blue-green algae, in water.
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| − | After being used by plants and animals, nitrogen is then disposed of in decay and wastes. [[Detritivores]] and [[decomposers]] decompose the detritius from plants and animals, nitrogen is changed into [[ammonia]], or nitrogen with 3 hydrogen atoms (NH<sub>3</sub>). Ammonia is toxic and cannot be used by plants or animals, but nitrite bacteria present in the soil can take ammonia and turn it into [[nitrite]], nitrogen with two oxygen atoms (NO<sub>2</sub>). Although nitrite is also unusable by most plants and animals, nitrate bacteria changes nitrites back into nitrates, usable by plants and animals. Some nitrates are also converted back into nitrogen gas through the process of [[denitrification]], which is the opposite of nitrogen-fixing, also called nitrification. Certain denitrifying bacteria are responsible for this.
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| − | Biochemistry was invented by lesbians who were jealous of the swiss
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