ni·tro·gen cy·cle

the series of events in which the nitrogen of the atmosphere is fixed, thus made available for plant and animal life, and is then returned to the atmosphere: nitrifying bacteria convert N₂ and O₂ to NO₂^- and NO₃^-, the latter being absorbed by plants and converted to protein; if plants decay, the nitrogen is in part given up to the atmosphere and the remainder is converted by microorganisms to ammonia, nitrites, and nitrates; if the plants are eaten, the animals' excreta or bacterial decay return the nitrogen to the soil and air.

Farlex Partner Medical Dictionary © Farlex 2012

nitrogen cycle

The circulation of nitrogen in nature, consisting of a cycle of chemical reactions in which nitrogen from the atmosphere is fixed in compounds in soil or water, assimilated by plants and animals, released to the soil and water through decomposition, and returned to the atmosphere through denitrification.

ni·tro·gen cy·cle

(nī'trŏ-jĕn sī'kĕl)

The series of events in which the nitrogen of the atmosphere is fixed, thus made available for plant and animal life, and is then returned to the atmosphere: nitrifying bacteria convert N₂ and O₂ to NO₂^- and NO₃^-, the latter being absorbed by plants and converted to protein; if plants decay, the nitrogen is in part given up to the atmosphere and the remainder is converted by microorganisms to ammonia, nitrites, and nitrates; if the plants are eaten, the animals' excreta or bacterial decay return the nitrogen to the soil and air.

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

Fig. 229 Nitrogen cycle .

nitrogen cycle

the circulation of nitrogen in the environment as a result of the activity of living organisms. 80% of the atmosphere is made up of nitrogen and this is maintained by the balancing action of the cycle.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

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References in periodicals archive

It has been reported that inoculating nitrifying bacteria maybe a viable alternative for promoting their development in the system.

Assessment of the nitrification process in a culture of pacific white shrimp, using artificial substrate and bacterial inoculum in a biofloc technology system (BFT)/Avaliacao do processo de nitrificacao no cultivo do camarao branco do pacifico Litopenaeus vannamei com uso de substrato artificial e inoculo de bacterias em sistema de bioflocos (BFT)

Isolation and identification of native nitrifying bacterial consortia: Based on the growth observed in the count of nitrifying bacteria, isolation and purification of native bacterial consortia were carried out through reseeding in a minimal mineral agar medium with a composition of 0.66 g [K.sup.2]HP[O.sub.4] x 3[H.sup.2]O, 1 g N[H.sub.4]Cl, 2 g NaS[O.sub.4], 0.2 g MgS[O.sub.4] x 7[H.sup.2]O, and 15 g of Agar-Agar in 1 000 mL of distilled water, adjusting the final pH to 7.5.

Aislamiento de cepas bacterianas oxidantes de amonio y nitrito del suelo y su uso potencial en la reduccion de nitrogeno en las aguas residuales domesticas

The final results of the total count of heterotrophic and nitrifying bacteria showed no significant difference between treatments (p [greater than or equal to] 0.05) and are presented in Table 1.

Cultivation of marine shrimp in biofloc technology (BFT) system under different water alkalinities/Cultivo de camaroes marinhos em sistema de bioflocos (BFT) sob diferentes alcalinidades da agua

Keywords: Low temperature heterotrophic nitrifying bacteria ICR mice Safety.

Identification of Low-temperature Oligotrophic and Heterotrophic Nitrifying Bacteria and Safety Tests with ICR Mice

During the experiment, we observed the presence of nitrifying bacteria inside the reactor at about 3% abundance, which would facilitate the processes of partial nitrification under oxygen limitation.

Crecimiento rapido autotrofico de microorganismos anaerobios oxidadores de amonio en presencia de nitrito, usando inoculos de Colombia

Effect of Mancozeb on Nitrifying Bacteria. The results on varying concentrations of mancozeb (0-2000 ppm) on nitrifying bacteria (Figure 2) showed gradual decrease in average number of nitrifying bacterial population from 2.14 log cfu at zero ppm to 1.44 log cfu at 2000 ppm.

Impact of fungicide mancozeb at different application rates on soil microbial populations, soil biological processes, and enzyme activities in soil

Copper is an essential trace element in nitrifying bacteria but becomes toxic as concentrations increase to levels that disrupt normal cellular function (Sato et al.

The influence of copper, lead and iron on stream sediment nitrification in central Indiana streams

The depletion of DO in the water, during the rainy season, may have limited the number of nitrifying bacteria in relation to heterotrophic bacteria on the water surface (HARGREAVES, 1998), but the dilution of the water during the rainy period, when rainfall was 240.8 mm, may have contributed to reduce the population of the latter, especially Streptococcus spp.

Physical and chemical water parameters and Streptococcus spp. occurrence in intensive tilapia farming in the State of Espirito Santo, Brazil/Parametros fisico-quimicos da agua e ocorrencia de Streptococcus spp. em criacao intensiva de tilapia no Estado do Espirito Santo, Brasil

Seasonal fluctuations are attributive to spore-forming bacteria, including Azotobacter and nitrifying bacteria. The number of bacteria decreases sharply at the soil withering.

The taxonomic composition of soil microorganisms in the ecosystems of southern chernozems of Northern Kazakhstan

"Nitrification potential is a sensitive indicator of stress because nitrifying bacteria are especially sensitive to toxic conditions," White explains.

Using manure to mend mine-damaged soils

As a result, the number of bacteria increased up to about four-fold and nitrifying bacteria, which decompose ammonia, intensified their activities some 1.5 times, they said.

Nano-level oxygen bubbles found useful to purify lake