By Olga Gertcyk
20 December 2016
(The Siberian Times) – In just two years, since the sponge was last surveyed, it has entirely vanished in the area around popular tourist resort Listvyanka and Cape Tolsty, in Irkutsk region, and over a wide area in the north of the crescent-shaped lake which contains around 20% of the world's unfrozen freshwater.
One theory is that the lesion of the sponge in coastal areas is caused by the impact of tourists, and the pollution that accompanies them, and the consequent growth of harmful foul-smelling algae.
Igor Khanaev, of the Limnological Institute, in Irkutsk, said referring to the Listvyanka area: 'It is clear that the waste discharged by boats have seriously changed the ecosystem of the lake in this area.'
Another is that methane leaks from the lake - the deepest on the planet - could be a factor. There have been claims the sponge is suffering from an 'unknown disease' caused by bacteria. Baikal sponge of 5-7 centimetres cleanses per day up to 20 litres of water from bacteria and different minerals. [more]