Paleolimnological records of carotenoids and carbonaceous particles in sediments of some lakes in Southern Alps

Sediment cores up to 22 cm deep and water samples were taken from 4 oligotrophic or mildly productive Italian and Swiss lakes with a pH of 5.7-8.0. The trophic history of the sediments was reconstructed by stratigraphic analyses of organic carbon, organic nitrogen, algal and bacterial carotenoids. D...

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Bibliographic Details
Published in:Hydrobiologia 1994-01, Vol.274 (1-3), p.57-64
Main Authors: LAMI, A, MARCHETTO, A, GUILIZZONI, P, GIORGIS, A, MASAFERRO, J
Format: Article
Language:English
Subjects:
Earth sciences
Earth, ocean, space
Engineering and environment geology. Geothermics
Exact sciences and technology
Freshwater
Marine and continental quaternary
Pollution, environment geology
Surficial geology
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Summary:Sediment cores up to 22 cm deep and water samples were taken from 4 oligotrophic or mildly productive Italian and Swiss lakes with a pH of 5.7-8.0. The trophic history of the sediments was reconstructed by stratigraphic analyses of organic carbon, organic nitrogen, algal and bacterial carotenoids. Dating was principally by lead-210 techniques supplemented by caesium-137 analysis. Lake contamination by atmospheric deposition was assessed after nitric acid oxidation by counting carbonaceous particle concentrations. The distribution of the carotenoids, okenone and isorenieratene in 3 lakes indicated the importance of sulphur photosynthetic bacteria, some of which were strictly anaerobic. This indicated periods of very low oxygen and high hydrogen sulphide concentrations. Chlorophyta, Pyrrhophyta and Cryptophyta dominated the algal community. The increase of carbonaceous particles in the upper sediments of all lakes indicated that atmospheric contamination started in 1940-1950 and that recent acidification had begun in the poorly buffered lakes.
ISSN:0018-8158
1573-5117
DOI:10.1007/BF00014627