The first finding of aegagropilious, or algal balls, in the oldest freshwater Lake Baikal

Abstract

Free-floating algal aggregations, or aegagropilious, are a rare phenomenon known from some freshwater or marine environments worldwide. In September 2014, unusual green algal balls were washed ashore in Ludar Bay on the west coast of the northern basin of Lake Baikal. The paper describes these algal aggregations and characterizes their composition. The Baikal algal balls mainly consisted of green filamentous algae of the family Cladophoraceae, such as Cladophora glomerata, Rhizoclonium sp., and Chaetomorpha sp. Other prominent components of the balls were numerous filaments of Spirogyra and Oedogonium. These taxa are known for their rapid growth in response to nutrients increase. As the result of the hyperproduction of filamentous benthic algae in the coastal zone of Lake Baikal, new living forms such as aegagropilious-like aggregations have been occurring. The algal balls signify the adaptive capacities of the Lake Baikal algal communities and might retain their functioning in the natural ecosystem’s self-purification processes.