Biogeochemical Migration of Silicon in Wet Boreal and Tropical Ecosystems

Biogeochemical Migration of Silicon in Wet Boreal and Tropical Ecosystems Wet Boreal Ecosystems 

The modern biogeochemical accumulation of silicon species was monitored in various parts of northern Eurasia, like Island Greenland, European (Karelia and Kola peninsula) and the Asian part of Russia (Chukotka peninsula). Enlarged concentrations of silicon (15-30mg/L) were found in surface waters, especially in lakes. The source 

A similar modern accumulation of silicon, as opal mineral, was monitored in Boreal Peat ecosystems in Belarussia and in floodplains of varions rivers in the Central Russian Plain. The biogeochemical mechanism of this silicon species formation is connected with the evapotranspiration of ground waters enriched in silicon by plants and deposition of amorphous silicon (Kovda, 1984). 

On the other hand, the abundant silicon powder formation was monitored in Podsoluvisols and Phaerozems at 0.5-2.0 m depth in Forest Steppe Ecosystems of Central Russian Plain, Sonth Siberia, Amnr River valley, and Manjury region of China. In this case, the most reasonable explanation is connected with the deposition of silicon from glacial melting waters after the glaciation period. 

Periodic soil freezing leads also to the Si deposition from soil and ground waters as a powder, Si02 sand and opal-like materials. The physical mechanism of Si deposits formation dne to winter freezing is similar to that of summer evaporation. Diatomic algae seem to accelerate this process. The chemical composition of Si-containing deposits is shown in Table 27. 

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