LIPID PRODUCTION IN NATURAL PHYTOPLANKTON COMMUNITIES IN A SMALL FRESH-WATER BALTIC LAKE, LAKE-SCHOHSEE, GERMANY

1. Seasonal patterns in lipid production and the photosynthetic parame ters describing lipid production in Lake Schohsee (a small freshwater mono-dimictic and moderately eutrophic North German Baltic lake) were determined. 2. The mean Lipid fraction of C fixation (LIP-FCF) was 13. 2% (range 7.6-21%), measured bimonthly from January to December 1995. Periods of high nutrient concentration, low temperatures and particula r species of algae (diatoms and/or cryptophytes), were associated with the highest LIP-FCF values. 3. None of the static indicators of nutri ent status [dissolved nitrate, soluble reactive silica (SRS); C/N or N /P] are apparently related to the allocation of carbon to lipid in Lak e Schohsee. 4. The light saturation parameters (I-k:I-k-LIP) indicated that carbon fixation into lipid was saturated at much lower light tha n that of total carbon fixation. This suggested that carbon fixation i nto lipid was more light efficient than total carbon fixation. 5. The relative allocation of carbohydrate and protein was related to dayleng th and temperature, respectively.