Geochemical cycles nitrogen

Hudson R. J. M. et al. (1994). Modeling the global carbon cycle Nitrogen fertilization of the terrestrial biosphere and the "missing" CO2 sink. Global Bio-geochem. Cycles 8, 307-333. 

Biodegradation. Under aerobic conditions, biodegradation results in the mineralization of an organic compound to carbon dioxide and water and—if the compound contains nitrogen, sulfur, phosphorus, or chlorine—with the release of ammonium (or nitrite), sulfate, phosphate, or chloride. These inorganic products may then enter well-established geochemical cycles. Under anaerobic conditions, methane may be formed in addition to carbon dioxide, and sulfate may be reduced to sulhde. 

Figure 3. The general nitrogen model for illustrating the bio geochemical cycling in Forest ecosystems. Explanations for the fluxes 1, ammonia volatilization 2, forest fertilization 3, N2-fixation 4, denitrification 5, nitrate respiration 6, nitrification 7, immobilization 8, mineralization 9, assimilatory and dissimilatory nitrate reduction to ammonium 10, leaching 11, plant uptake 12, deposition N input 13, residue composition, exudation 14, soil erosion 15, ammonium fixation and release by clay minerals 16, biomass combustion 17, forest harvesting 18, litterfall (Bashkin, 2002).

Duce, R. (1986). The impact of atmospheric nitrogen, phosphorus and iron species on marine biological productivity. In The Role of Air-Sea Exchange in Geochemical Cycling (Buat-Menard, P., ed.). D. Reidel Publishing Company, Hingham, MA. pp. 497-529. 

Of the major volatile elements described above, water, a variety of carbon compounds, nitrogen and sulfur are the volatile compounds which dominate in the modern Earth. In this section we review the modern-Earth geochemical cycles for water, carbon, nitrogen, and sulfur and look in some detail at volatile mass balances between the Earth s surface reservoirs and the deep Earth. Then, having established how the modern Earth works we seek to determine how these geochemical cycles might have operated in the early Earth. 

Christensen J.P., Murray J.W., Devol A.H., Codispoti L.A. (1987) Denitrification in continental shelf sediments has major impact on the oceanic nitrogen budget. Glob. Bio-geochem. Cycles 1, 97—116. 

Most of the sampling carried out In the atmosphere is intended for the determination of pollutants or their effects in localized industrial areas or areas devoted to global environmental studies. Only ocassionally (e.g. measurements of boron [19] or nitrogen oxides in air [20]) are these studies aimed at the Identification of the geochemical cycle of some species in the atmosphere. 

Thus, denitrification prevents fixing nitrogen and returning it in the bio-geochemical cycle. Oxidizing of organic matter in the process of denitrification looks like this... 

Microorganisms are omnipresent in the environment bacteria, algae, lichens, fungi etc. They play an important role for all forms of life and for the geochemical cycles of elements such as the carbon, nitrogen and sulfur [30]. They can also affect the corrosion rate of metals. 

In regions of the globe where the concentrations of sulfur oxides and nitrogen oxides are unusually high, due primarily to the combustion of fossil fuels, rainwater consists of a mixture of sulfuric acid, nitric acid, and water as well as other chemicals. In such circumstances, the pH of rainwater can reach values of 4 or lower. This is the phenomenon of acid rain, which can cause damage to fish, soil, crops, and property. It also has important consequences for geochemical cycling of various minerals and their constituent elements. 

Changes from one compartment to another are known as phase transitions, as compounds can transition from solid to liquid to gas. For elements and small molecules, these transitions are intimately associated with geochemical cycling as elements naturally transition from one phase to another. The common elements carbon, nitrogen, and phosphorus have the vast bulk of their matter locked up in solid form within the crust of the Earth, where they may remain stable for eons. A much smaller pool of these molecules may transition from solid to being dissolved in water, to being volatilized into the atmosphere. 

Source Smil, V. 1999. Nitrogen in crop production an account of global flows. Global Bio-geochemical Cycles 13 647-662. All figures are rounded to avoid the appearance of unwarranted precision. 

Biogeochemistry- Study of microbially mediated chemical transformations of geochemical interest, such as nitrogen or sulfur cycling. 

Smith, S. V., and HoUibaugh, J. T. (1998). Carbon-nitrogen—phosphorus cycling in Tomales Bay, California. Aquat. Geochem. 4, 395-402. 

---