Polycyclic Aromatic Hydrocarbons in the Surface Microlayer of Lake Baikal during Wildfires and Naphthalene-degrading Strains from the Bacterioneuston

— The summer of 2015 was characterized by a large number of forest fires along the coastline of Lake Baikal. The concentrations of all analyzed polycyclic aromatic hydrocarbons (PAHs) in the surface microlayer of Lake Baikal during wildfires in August 2015 were significantly increased compared to August 2017, when there were fewer fires. Among the PAHs, naphthalene, phenanthrene and pyrene dominated in the surface microlayer in August 2015, while in August 2017, only naphthalene and its derivatives were prevalent. To evaluate the PAH-degrading capacity of the strains Pseudomonas sp. P30, Microbacterium sp. NC4, Massilia sp. NC8, Flavobacterium sp. NC135, Pseudomonas sp. NC83, and Bacillus sp. P29.2.1 isolated from the Lake Baikal surface microlayer, a laboratory-based experiment was established. Suspension cell cultures in mineral medium were set up in flasks, and naphthalene was added as the only source of carbon. Flasks were incubated for 5–20 days at a temperature of 18°С. It was shown that the strains could effectively biodegrade naphthalene.