Changes of algal biomass as carbon, cell number and volume, in bottles suspended in Lake Constance

Changes of algal biomass, as carbon, cell numbers and volumewere determined for phytoplankton of Lake Constance suspendedin situ in 2 l glass bottles. Phytoplankton placed at the 6%surface penetrating light level (photosynthetically availableradiation) were close to the compensation depth for growth estimatedas total particulate carbon and total cell volumes. Cell countsof individual alga] species however, showed appreciable growthof diatoms offset by the decline of flagellates. Bottles suspendedat two shallower depths in a separate experiment showed somegrowth of all species and indicated a vertical niche separationof growth of Rhodomonas minuta Skuja and R. lens Dascher andRuttner in accordance with their vertical distribution. ^*This paper is the result of a study made at the Group for AquaticPrimary Productivity (GAP) First International Workshop heldat the Limnological Institute, University of Konstanz, in April1982.