Vorläufige Mitteilungen über das Vorkommen des aus Purpurbakterien stammenden Pigmentes Okenon in Seesedimenten

The isolation of the carotenoid Okenone from the sediments of several shallow lakes gives evidence of anaerobic zones existing during the sedimentation 13 000 years before.     

Limnological investigation of biogenic silica sedimentation and silica biogeochemistry in Lake St. Moritz and Lake Zürich

Biogenic silica concentrations were determined from core samples of laminated sediments collected from Lake Zürich and Lake St. Moritz and used to calculate rates of biogenic silica sedimentation. In Lake Zürich biogenic silica sedimentation increased from 65 g SiO₂·^?2·yr^?1 in 1894 to nearly 900 g SiO₂·m^?2·yr^?1 in 1896 and in Lake St. Moritz biogenic silica sedimentation increased about 6-fold during the 1930s. Both periods of increased biogenic silica flux followed increased loadings of domestic sewage to the lakes. In Lake Zürich the period of increased flux only lasted for a few years whereas in Lake St. Moritz high fluxes were maintained to the top of the core. In Lake Zürich increased production and sedimentation of diatoms could be maintained only until the silca reservoir in the water mass was depleted whereas in Lake St. Moritz (0.10 year residence time and a mean depth of 25 m) diatom production and sedimentation was maintained at a high level by rapid replenishment of silica from tributary inputs. Although historical patterns of biogenic silica sedimentation differed for the two lakes, it is hypothesized that increased biogenic silica deposition in both lakes occurred because diatom production was stimulated by phosphorus enrichment of the water mass and that the silica biogeochemistry of both lakes was affected as a result.     

Pigmente phototropher Bakterien in Seesedimenten und ihre Bedeutung für die Seenforschung

Sediments of shallow lakes contain besides plankton pigments as well pigments of purple non-sulfur and purple sulfur bacteria. A thin-layer chromatographic method was developed for the separation of the most important pigments of purple bacteria beside plankton pigments. The new method was examined in three different lakes for a stratigraphic analysis of bacteria pigments beside plankton pigments and the results were discussed subsequently.      

Hydrographie in Gegenwart und Zukunft

Ohne ZusammenfassungVortrag gehalten am 25. September 1986 in Hamburg.     

Zur Kenntnis der präkambrischen,schichtgebundenen Molybdänitvorkommen in Südnorwegen

The southern Norwegian molybdenum deposits have hitherto been looked upon as typical examples of deposits of pneumatolytic — catathermal origin formed by emanations from intrusive granites. It is now demonstrated that all these deposits are to be found stratabound in a series of grey gneisses. They are accompanied by varying amounts of graphite and apatite of biogenetic origin and all of them show the same sulphide and oxide ore mineral paragenesis. It is concluded that the concentration and precipitation of metals took place in marine environments. Both the ores and their host rocks later underwent the same highmetamorphic processes.