Increasing silicon concentrations in Bohemian Forest lakes

J. Veselý, V. Majer, J. Kopácek, J. Safanda, S. A. Norton
2005 Hydrology and Earth System Sciences  
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
more » ... s 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.
doi:10.5194/hess-9-699-2005 fatcat:vtruu644cbes7ip7nwsasqc3by