Lake phytoplankton quantification by chlorophyll a, comparative study of spectrophotometry and FluoroProbe

A comparison of spectrophotometry and submersible fluorescence probe as methods for quantification of chlorophyll a content and phytoplankton diversity was performed in lake Gransjön, located in middle of Sweden.The values ranged from 2.49 μg/l to 7.91 μg/l, but did not correspond between the tested methods. Algae communities were examined via FluoroProbe and inverted microscopy technique. Therewere nine algae groups distinguished. Chlorophyta tended to dominate while Trebouxiophyceae, Xanthophyceae and Zygnematophyceae were at the least significant. Both methods gave similar results regarding common respectively uncommon groups among phytoplankton. The lake was regarded an oligotrophic, characterized by low productivity.