A new paper from Timoshkin et al. in Hydrobiological Journal describes a previously unrecorded phenomenon in Baikal: massive mats of filamentous green algae (Spirogyra and Stigeoclonium) have been appearing in autumn along the shores of the lake.
In the article, “Mass development of filamentous algae of genera Spirogyra and Stigeoclonium (Chlorophyta) in the coastal zone of southern Baikal”, Timoshkin et al. analyze data from the western shore of the lake’s south basin from 2003 and 2008-2013. In the years 2011-2013, late autumn blooms of Spirogyra and Stigeoclonium dominated study sites, replacing the more common Ulothrix zonata. The species of Spirogyra present at these sites, Spirogyra fluviatilis, had not been recorded in the lake before. Such massive blooms of Spirogyra can degrade water quality, say the authors.
The dearth of research on benthic algae in the last 15 years prevents us from determining exactly when these blooms began appearing, but they seem to be a relatively new occurrence. Stigeoclonium blooms were also found in other parts of the lake in 2013: the western shore of Maloe More and the tip of the north basin.
Timoshkin et al. suggest that these blooms may be the result of increased nutrient inputs into the lake. They point out that tourism in the area has increased in recent years, and some settlements near Baikal’s shore lack centralized sewage treatment facilities. However, scientists have not yet demonstrated changes in nutrient levels in these areas, so it is difficult to say with certainty whether the blooms are a result of human impacts or natural cycles.
Тимошкин, О. А., Бондаренко, Н. А., Волкова, Е. А., Томберг, И. В., Вишняков, В. С., & Мальник, В. В. (2014). Массовое развитие зеленых нитчатых водорослей родов Spirogyra и Stigeoclonium (Chlorophyta) в прибрежной зоне южного Байкала. Гидробиологический Журнал, 50(5), 15-26.