Nutrients biogeochemical cycles

Biogeochemical cycling in forests includes elemental inputs, exports, and a complex set of physical, chemical and biotic processes which comprise internal nutrient cycles (Fig. 1). Any disturbance, whether anthropogenic (i.e. 

Biomass Redistribution Associated with Deforestation and Fire. The influence of deforestation on biogeochemical cycles is dependent upon a number of factors associated with the unique characteristics of the ecosystem (climate, soils, topography, etc), the quantity of the total nutrient pool stored in aboveground biomass (Table II), and the level of disturbance (i.e. the degree of canopy removal, soil disturbance, and the quantity of wood or other forest products exported from the site). The quantity of biomass consumed by one or more slash fires following deforestation can also dramatically increase nutrient losses, influence post fire plant succession, and hence, postfire biogeochemical cycles. 

Williams, G. R. (1987). The coupling of biogeochemical cycles of nutrients. Biogeochemistry 4,61-75. 

Anderson, L. A. and Sarmiento, J. L. (1994). Redfield ratios of remineralization by nutrient data analysis. Glob. Biogeochem. Cycles 8,65-80. 

The evolution of life on Earfh has depended on a sustained supply of nutrients provided by the physical environment. Life, in turn, has profoundly influenced the availability and cycling of these nutrients hence the inclusion of bio in biogeochemical cycles. The involvement of the biosphere with biogeochemical cycles has been determined by the evolution of life s biochemical properties in the context of the physical and chemical properties of planet Earth. 

We can see that the content of trace metals in water extraction is very low. This means that the direct involvement of these metals in biogeochemical cycles is very restricted. The significant increase of metal contents in acid-soluble form was shown only for Fe, Mn and, partly, for Zn. These data testify the importance of atmospheric deposition for the Arctic ecosystems as a source of nutrients. 

A high amount of various nutrients and trace metals is retained in peat and dead plant residues and thus temporarily eliminated from the biogeochemical cycles and pollutants exposure to human and ecosystem health. The period of this elimination depends on the solubility of these metals. It has been shown (Dobrovolsky, 1994) that... 

Since nitrogen is a nutrient, which limits the productivity of almost all Boreal and Sub-Boreal Forest ecosystems, its biogeochemical cycling is relatively well understood at present. The major N transformations and fluxes are shown in Figure 3. 

The possible explanation of these results is related to the construction of dikes in this area a few years prior to the experiment. This changed the biogeochemical cycles of many nutrients in natural ecosystems too. Furthermore, the input of nutrients with flooded waters was not taken into account. 

The main specificity of biogeochemical cycling and exposure pathways in Tropical Rain Forest ecosystems is related to its almost closed character. This means that almost the total number of nutrients and/or pollutants is re-circulating in biogeochemical cycles (Figure 1). 

Considerable evidence exists that human activities have already perturbed parts of the interlinked global biogeochemical cycles of the nutrients, micronutrients, carbon, and O2. Some of these perturbations are the consequence of climate change and others are associated with changes in the rates of input of nutrients and iron to the sea. As... 

Vertical segregation The vertical gradient in biogenic materials, such as nutrients and O2, that is established by the interaction between the biogeochemical cycling of particulate organic matter and the vertical density stratification of the water column. Strongest at mid and low latitudes. 

Nutrient (biogeochemical) cycles Development and evolution Control... 

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