Carotenoids from plankton and photosynthetic bacteria in sediments as indicators of trophic changes in Lake Lobsigen during the last 14000 years
- Cite this article as:
- Züllig, H. Hydrobiologia (1986) 143: 315. doi:10.1007/BF00026676
Previous examination of drilling cores showed that the majority of the carotenes and carotenoids originally present in the various planktonic organisms and phototrophic bacteria are preserved in sediments. The indicator pigments for algae phyla are: Lutein for Chlorophyta, Myxoxanthophylls and their derivatives for Cyanophyta, Fucoxanthin for Chrysophyta, and Alloxanthin for Cryptophyta.
The pigments in the deepest sediment sample (late glacial time, clay, 12.83 m) consists primarily of Alloxanthin, secondly of Lutein and β-carotene and thirdly of traces of Okenone, Speroidenone and other such bacterial carotenoids. The first plankton organisms were thus Cryptophyta and some Chlorophyta. The presence of the phototrophic bacteria pigments indicates that at the time of sediment formation, anaerobic conditions prevailed at the lake bottom.
The Holocene era commences at a depth of 8.55 m and is characterized by the first occurrence of Myxoxanthophyll and Echinenone from Cyanophyta, as well as by a rapid increase of β-carotene, Lutein and Alloxanthin. The pronounced occurrence of Oscillatoria rubescens (‘blood of the Burgundies’), characterized by Oscillaxanthin at 8.21 m must be considered for Swiss lakes as a very surprising discovery.
The intensive plankton production again lead to stringent anaerobic conditions. Predominant among phototrophic bacteria pigments were Okenone, Spheroidene and Rhodopin.