Seasonal variations of dominant phytoplankton in humic forest lakes

This work presents the community composition, abundance and seasonal dominance of phytoplankton taxa in three hydrochemically different, mid-forest humic lakes. The largest number of taxa was observed in the oligohumic lake (76), with smaller numbers seen in the mesohumic (42) and polyhumic lakes (37), which were characterized by higher contents of dissolved humic substances carbon (DHSC). Along an increasing gradient of DHSC in a pool of dissolved organic carbon (DOC) the autotrophic algae were seen to disappear, being replaced by taxa with features of facultative heterotrophs and flagellated algae that are able to move in the water column.