Increasing silicon concentrations in Bohemian Forest lakes

Abstract

Long-term trends of dissolved silicon (Si) concentrations in five glacial lakes in the Bohemian Forest, Czech Republic, recovering from acidification show higher mobility of Si from the soil to surface waters despite lower atmospheric deposition of acids. Si increased by 0.95 to 1.95 µmol yr 1 (36 to 51%) from 19862004 and with increasing pH. A change in soil solution conditions because of a sharp decrease in acidic deposition has led to marked decline in Al mobility and to considerable decreases in dissolved Al, especially Al 3+ . The increase in Si may be related to: (1) unblocking of the inhibitory effect of dissolved Al on weathering of aluminosilicates, (2) biogenic opal (phytoliths) dissolving faster, and/or (3) lower Si precipitation as secondary aluminosilicates in soil. The change in Al speciation on the dissolution rate of biogenic silica is critical. A lack of change in Si at sites outside central Europe may be explained by small or no decline in mobility of dissolved Al. The effect of a long-term increase in temperature was probably minor.

Assessment of Spatio-temporal Variations of Selected Water Quality Parameters of Lake Ziway, Ethiopia Using Multivariate Techniques

“…Higher concentration of SiO 2 -Si was found in dry season compared to wet season, this might be because of dilution in the wet season. Similar results were reported by Vessely et al (2005). Signi cant uctuations in mean SiO 2 -Si concentrations were observed over the different seasons and across the different sampling sites in the Lake.…”

Deforestation causes increased dissolved silicate losses in the Hubbard Brook Experimental Forest

“…However, the increase in diatom biomass is not currently sufficient to remove significant quantities of DSi. By contrast, increasing DSi concentrations have been observed in lakes in the Bohemian Forest, Czech Republic, and attributed to recovery from acid deposition and changes in Al biogeochemistry (Vesely et al , 2005).…”

Tracing the origin of dissolved silicon transferred from various soil-plant systems towards rivers: a review

“…Similarly, some fraction of the DSi exported from a deforested temperate ecosystem derive from the dissolution of a biologically derived pool of ASi (phytoliths), which supports the impact of Si biocycling in this environment . In a Bohemian forest, despite lower atmospheric deposition of acids, the higher leaching of DSi in five glacial lakes could be explained by the decline of Al activity and increase in silicate weathering by BSi dissolution (Veselý et al, 2005). In the wet climate of the Buenos Aires province, ASi from volcanic or biogenic origin is likely responsible for the high concentration of DSi (1 mM) in the shallow groundwater (Miretzky et al, 2001).…”