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 (3-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 /3-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 .

Species composition and density of cladoceran populations changed in Lakes ZUrich, St. Mortiz and Baldegg as human populations increased in these watersheds. Lake ZUrich sediments became annually laminated in the 1890's as a result of increased organic input as the size of the cities surrounding the lake grew. At the same time, the Bosmina species changed from a oligotrophic form (longispina) to a eutrophic form (longirostris). An increase in Daphnia spp. populations also occurred at this time in the lake's history. Bosmina longispina reappeared in the lake in 1965 as the lake's trophic status changed from eutrophic to mesotrophic due to effective sewage treatment facilities. Annual laminations appear in the Lake St. Moritz sediments about 1910. Shortly thereafter, a shift from B. longispina to B. longirostris occurred. This change in trophic status is associated with increased tourism in the area. Lake Baldegg sediments also show annual laminations beginning in 1885 and a similar shift in the Bosmina species. Other cladoceran remains were too scarce to be useful in interpreting the histories of these lakes.