Project Number: 3100-027375
||01/01/1987 - 05/31/1993 project completed
||Prof. Ferdinand Schanz
Institut für Pflanzenbiologie
Phone: +41 (0) 44 910 86 44 ; +41 (0) 44 634 83 79
FAX: +41 (0) 44 634 82 04
| environmental sciences|
| hydrology, limnology, glaciology|
high mountain lakes
in situ- experiments
Swiss alpine region
historical development of acidification
The investigations have been done in lakes of the following regions of Switzerland: Bellwald (Goms, canton Wallis), Cristallina (north part of canton Tessin), Gotthard (central Switzerland) and Macun (near Lavin, Engadin, canton Graubünden). The regions of Cristallina and Gotthard are severely influenced by acid precipitation; a much smaller influence was found to be into the regions Bellwald and Macun. It was recognized that several mechanisms of buffering must have an important influence in reducing the chemical effect of acid precipitation. Nevertheless, the today values of acid input lie below those measured 10 years ago. The periphyton diatom communities in the alpine lakes changed with the pH of the water. The highest number of different taxa has been found in the pH range from 6.0 to 6.5. The pH values of the lakes and its correlated factors influenced mainly the epilithic diatom communities as it could be demonstrated by means of cluster and correspondence analysis. To use the diatom taxa for pH estimations it was necessary to find out the pH range of the water bodies for every taxum and the most preferred pH (the water bodies with the highest frequencies). Based on these results we could reconstruct the historical development of the pH value in the Lago della Zota (Cristallina) and in the Lengsee (Bellwald) using the diatom communities or different sediment layers. Both lakes showed a similar patteril of acidification: the pH values scattered in the range from 5.7 to 5.9 until the end of the 19th century; since then an increasing acidification was observed.
1 ) Which influence have the hydrogen ions of sulfuric, nitric acid, and ammonia on the acidification of high alpine lakes?
2 ) Which differences are recognizable in the amount of acid input into the four regions chosen for investigations (Bellwald, Cristallina, Gotthard, Macun)?
3 ) Which factors influence most the community structure of periphyton diatoms in the lakes? Is there a possibility to explain differences in the community structures by means of differencies in the chemical characteristics of the lakes?
4 ) Which are the pH preferences of diatom species in high alpine lakes (pH ranges of the lakes where they occur, pH optima)? If using these diatom species: Are the reconstructions of pH values of the lakes investigated correct?
5 ) Which is the historical development of the acidification of the Lago della Zota (Cristallina) and the Lengsee (Bellwald)?
Niederhauser,P. & F.Schanz, 1993a. Effects of nutrient (N,P,C) enrichment upon the littoral diatom community of an oligotrophic high-mountain lake. In H.Van Dam (ed.), 12th International Diatom Symposium. Dev.Hydrobiol. (in press).
Niederhauser,P. & F.Schanz, 1993b. Comparison of diatom communities in remote high-mountain lakes using index B and cluster analysis. In J.Fott (ed.), Limnology of mountain lakes. Dev.Hydrobiol. (in press).
Schanz,F., 1984. Chemical and algological characteristics of five high mountain lakes near the Swiss National Park. Verh.Internat.Verein.Limnol. 22:1066-1070.
Schanz,F., 1987. Beurteilung des Einflusses von sauren Niederschlägen auf das' Macun-Gebiet im Unterengadin (Schweiz). Verh.Ges.Oekol. (Graz 1985) 15:249-255
Last update: 12/23/16
Source of data: ProClim- Research InfoSystem (1993-2020)
Update the data of project: CH-27375