Vertical distribution of phototrophs in the pelagic zone of three small Lobelia lakes

Abstract

The community structure and biomass of pelagic phototrophs, with a particular focus on the picoplanktonic fraction, were studied in three small, soft-water lakes in the Pomerania Lake District (north Poland). The smallest phototrophs were usually dominated by picocyanophytes, both single-celled and colonial. Picochlorophytes were less frequent, and they formed dense populations only in one lake. The nano-and microplankton included many groups of organisms, but the main groups were comprised of dinoflagellates, chrysophytes and chroococcoid and/or filamentous cyanophytes and large raphidophytes. Community structure changed significantly with depth and in all lakes remarkable differences were observed between the epilimnion and both the meta-and hypolimnion. The hypolimnion was characterized by the presence of photosynthetic green sulfur bacteria or their symbiotic consortia.

The Effect of Human Impact on the Water Quality and Biocoenoses of the Soft Water Lake with Isoetids: Lake Jeleń, NW Poland

“…The results of phytoplankton surveys from 2004 to 2018 show that species richness increased to over 50 taxa-a high value for SLI in Poland. The dominance of green algae with the codominance of cyanobacteria observed in Lake Jeleń is characteristic of the array of summer phytoplankton of many other Polish SLI [37][38][39][40][41][42][43]. Considering phytoplankton biomass, in the light of the criteria of Heinonen [44], an increase of trophy of the epilimnetic zone from olig-meso to mesoptrophic was found.…”