Identification of filamentous green algae from an area of local biogenic pollution of Lake Baikal (Listvennichnyy bay) using SSU 18S rDNA molecular marker

Background. A local eutrophication process is noted for the first time in Listvennichnyi bay in Lake Baikal. High level of biogenic elements in the water of the bay led to nuisance growth of filamentous algae. Rapid identification of these algae's taxa was necessary to assess ecosystem damage in the polluted area of the lake. Materials and methods. We determined a boundary of bottom fouling by locating transects ranging from 0 to 10 meters in different areas of the bay. Algae samples were examined using microscopic techniques as well as SSU 18S rDNA sequencing. Phylogenetic trees were estimated using Bayesian inference (BI) based on SSU alignment. Results. Our results showed intensive filamentous algae fouling in depth from 3 to 10 meters along the coastline of the eastern part of the bay. Morphological and molecular analysis demonstrated prevalence in samples of Ulothrix zonata (Web. et Mohr) Kutz. Using SSU 18S rDNA sequencing data we also showed presence of three species of Spirogyra Link. genus. Conclusion. Detection of Spirogyra species which are normally not typical for such areas of the lake along with Ulothrix zonata extended more deeply than usually observed reveals severe phytocenosis disturbance of the polluted part of Lake Baikal.