On the question – if Spirogyra disappeared?

The swash zone of Lake Baikal, observable from the shoreline, appears to be deprived of any aquatic vegetation; however, a closer examination reveals an unusual abnormal growth of benthic algae, among which filamentous algae of the Spirogyra genus dominate.

Currently, in Listvyanka settlement, one type of Spirogyra, referred to as “morphotype No. 1”, shows rapid growth.

Mass development of this species has been observed in the coastal zone of Lake Baikal since about 2010. Currently, this species is developing in mass almost throughout the entire coastal zone (except for the Ushkany Islands). Typically, the most significant growth of the species is in rocky soils located near coastal settlements, with a distribution depth ranging from 1 to 6 meters, depending on the water level in the lake. The preferred depth of mass growth of algae is 2-4 m. This alga never settles on the water's edge. Multiple but relatively short spirogyra threads 1-2 cm long usually appear at the end of August; the peak of growth occurs at the end of the recreational season (September-October). In late October-November, the length of the “curls” can reach 5-7 cm or more. In this case, the filaments were at the stage followed by maximum maturity, or “homogeneous chloroplast.”

The chemical composition of water may not reveal any significant deviations upon the introduction of biogenic components (such as phosphorus and nitrogen) into the aquatic environment. However, the abnormally massive development of phytobenthos indicates that this is happening, and in the case of Listvyanka, the supply of these components is year-round.