Biogeochemical cycles of individual elements

As is known, the three chemical elements - oxygen, carbon and hydrogen - 98% of the total mass of living matter, wherein the first of them represents 70, the second - 18, and the third - 10%. Unlike most of the oxygen and hydrogen present in the body in the form of an aqueous substance (a solvent and a medium for biochemical reactions), carbon is essentially structure-forming component. In science, a well-known ability to easily form a carbon carbon - carbon bonds, to make the polymer chains and rings, serve as the basis for a variety of organic compounds.
During the long evolution of the biosphere in the distribution of carbon have been significant changes. A huge amount of carbon appeared concentrated at the bottom of the ocean in the form of poorly soluble calcium carbonate and carbonate sedimentary strata in the lithosphere as caustobiolites etc.. Etc.. Lot of carbon in the biomass is concentrated in the bodies of land and sea, in the atmosphere, gumosfere. The driving force behind today's global carbon cycle is the biological cycle proceeds as follows: "bioassimilyatsiya carbon from the atmosphere, aquatic or terrestrial environments plants, consumption of organic compounds in animals and humans, the oxidation of organic matter to carbon dioxide during respiration and decomposition of waste, return of carbon dioxide in the atmosphere. "
The carbon cycle on land and in the ocean is not the same: it is mostly on land back into the atmosphere, the ocean remains largely in solution. It is known that the ocean is a semi-autonomous system in gas exchange with the atmosphere, indicating a slow exchange of carbon dioxide in the "ocean - atmosphere." As for the system of "land-ocean", here dominated by unilateral migration of carbon in the form of the removal of this item from the land in the carbonate and organic compounds.
A huge scientific interest is the oxygen circuit - one of the most important elements in nature, due in part to growing its consumption for industrial and other purposes. It is believed that mankind is primarily face a shortage of oxygen is because it burns every year about a quarter of this element produced by terrestrial vegetation.
Starting intensive accumulation of oxygen in the atmosphere associated with the spread of photosynthetic elements about 2 billion years ago. In the process of long-term evolution of the global circulation of oxygen largest portion of this element has remained in the atmosphere, the other part was dissolved in the ocean, and the third was fixed in the earth's crust in the form of sulfates, carbonates, and various oxides.
Relatively less studied the global nitrogen cycle, mainly due to difficulties in assessing the components of the cycle. Still do not know exactly which organisms are able to fix nitrogen, translate it in such chemical compounds that can be used by living organisms. Meanwhile, in the biological cycle of the huge stock of nitrogen in the atmosphere and sedimentary shell of the lithosphere is involved only fixed nitrogen assimilable by living organisms land and ocean. In general, in vivo binding processes and release nitrogen balance each other.
Of certain interest is the sedimentary cycle of phosphorus - quite rare element in the biosphere (the earth's crust its contents do not exceed 1%). Phosphorus cycle diagram on land as follows: "uptake by plants of inorganic phosphorus, its translation into the living matter of plants and animals (and people), the return of organic phosphates with corpses, waste and excrement of living beings in the land, processing of phosphates by microorganisms."
A completely different situation occurs in the reservoirs, which is associated with the deposition of dead organisms on the bottom of the pond, and their accumulation in sediments. It is well known that the decomposition of organic matter near the bottom often occurs at slow speed due to an insufficient supply of oxygen. As a result, phosphorus mineralized forms an insoluble complex with the trivalent iron and thus is already unavailable for uptake by aquatic organisms. However, this is not the only "taking" of the global phosphorus cycle. Large amount of it is made in the world's oceans, the same rate of return migration (birds and fisheries products) is considerably smaller. An example of the global cycle of phosphorus shows how dangerous are any maloobdumannye human impact on the natural course of biogeochemical processes in the biosphere.

We have considered some cycles critical to the biosphere elements show the great importance of maintaining the existing dynamic equilibrium in a single global biogeochemical cycles.