Summer Phytoplankton Primary Production and Biomass in An Alpine Lake, Mondsee (Austria)

Authors: Ayşe Nilsun BAKAN, Martin DOKULIL

Abstract: In this study, phytoplankton primary production, phytoplankton biomass, light and temperature were investigated in depth profiles during late summer in Mondsee, Austria. During the research period, the highest and the lowest primary production was estimated at 29.4 and 0.2 mg C/m3.h at 2 and 12 m depth, respectively. The maximum rates of production occurred at low light transmission on the 5th of September. Integral primary production varied from 100.7 to 154.6 mg C/m2.h. Phytoplankton biovolumes increased towards the end of the experimental period. Chlorophyll a varied from 0.56 to 3.65 mg/m3. The depth profiles of primary production showed a similarity to phytoplankton biomass. During the research period, the composition of phytoplankton ranged from Cryptophyceae to Cyanophyceae by the dominance of Microcystis aeruginosa. Dinophyceae, Chlorophyceae and Chrysophyceae were usually low in number while Bacillariophyceae species increased during the research period.

Keywords: Primary production, phytoplankton biomass, depth profiles, Alpine lake.