We investigated the soils of a model site in Severnaya Bay, affected by the 2015 fire, on Bolshoi Ushkanii Island (Lake Baikal). Blue-green algae bloom in the coastal zone and its release to the shore we observed in this bay in summer 2016. To study the soils at two points of observation (a high and a low-intensity fire), the approach of geochemical conjugate sections applied. Wildfire strongly affected top soils horizons (4‒5 sm), there are charred roots biomass, soot, charcoal, and structural aggregate stability is changed. Migration and accumulation of total organic carbon, N‒NH4, mobile phosphates,  detected at the foot of the slope, which is 1,5‒3 times higher than the content of these elements in unburned soil. The slope migration of pyrogenic carbon is traced studying polyaromatic hydrocarbons (PAHs). At 80‒90%, PAHs are represented by a Retene − а marker of wood combustion. Post-pyrogenic slope erosion was detected a year after the fire in Severnaya Bay. Biogenic elements migration and accumulation in the beach area (including interstitial water) can have consequences as a potential factor in the eutrophication of Lake Baikal coastal zone.