The fresh water layer has disappeared and the toxic layer rose by 2 meters in Lake Mogilnoye on the Kildin Island in the Barents Sea, the Murmansk Arctic State University press service reports.

Mogilnoye has three layers: fresh water on the surface, then a sea water layer and a toxic hydrogen-sulphide layer at the bottom. The toxic layer has gone up by 2 meters and the freshwater layer grew thinner and has disappeared altogether over the past 10 years.

"These changes are undoubtedly unfavorable because the lake is losing its unique nature. It is a habitat of relict flora and fauna, including Kildin cod; however, these changes make Mogilnoye lose its biological diversity," project manager Pyotr Strelkov said.

He believes that this is happening because the spring that runs into the lake has dried out completely. The reduction of the freshwater inflow has led to the disappearance of the freshwater layer. This could indirectly stimulate the rise of the toxic hydrogen-sulphide layer.