Аннотация:In July and August 2018, two expeditions were organized to the relict lake Mogilnoye (Barents
Sea, island Kildin) to study its current condition. Has the top fresh water layer really disappeared? Has the position of the hydrogen sulfide distribution boundary changed? Why could this happen? Is there a pink bacterial layer that protected the aerobic zone from toxic hydrogen sulphide, and what kind of
phototrophic microorganisms are responsible for its color today? The report is devoted to the results of research carried out by a joint expeditions of Moscow and St. Petersburg State Universities.
