Alpine lakes acidification

Acidification Effects on High-Altitude Alpine Lakes. 125... 

In order to verify whether atmospheric deposition directly affects surface water chemistry of high-altitude Alpine lakes, trend analyses were performed for 20 mountain lakes with low alkalinity on the key variables involved in acidification and recovery alkalinity (Gran alkalinity), pH, sulphate, nitrate, base cations (calcium + magnesium). The analysis covers the period 1980-2004 and allows a comparison between atmospheric inputs and surface water quahty. 

At present two of 20 studied high Alpine lakes are still acid (Aik <0 meq P ), 13 are sensitive to acidification (0 acid sensitive (0.05 meq 1 < AUc <0.2 meq 1 ). In the 1980s the number of acid, acid sensitive, and not acid sensitive lakes was 4, 14 and 2, respectively. Because of the increase in aluminium dissolution a pH decrease below 6 can become critical for the biology of lakes. Today only three lakes from 20 have an average pH below 6. In the 1980s there were seven. 

Guilizzoni, P., A. Eami A. Marchetto, 1992. Plant pigment ratios from lake sediments as indicators of recent acidification in alpine lakes. Eimnol. Oceanogr. 37 1565-1569. 

Zobrist, J., and J. I. Drever (1990), "Weathering Processes in Alpine Watersheds Sensitive to Acidification", in M. Johannessen, R. Mosello, and H. Barth, Eds., Air Pollution Research Report 20 "Acidification Processes in Remote Mountain Lake", CEC, Brussels, 149-161. 

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