Bubbles of frozen methane seen through crystal clear ice of lake Baikal.
© Stanislav Tolstnev
Bubbles of frozen methane seen through crystal clear ice of lake Baikal.
A tranquil video of white and silver bubbles of methane caught in newly-formed ice was filmed at Maloye More, a strait that separates the lake's largest island of Olkhon from the western shore of Lake Baikal.

'Ice covering the shallow straits and bays begins to form by the end of November, while the rest of Baikal freezes by the middle of January.

'This kind of ice, the purest, can only be seen in some areas of the lake in November and December', said Stanislav Tolstev, 46, photographer and tour guide from Irkutsk.

'The first time I paid attention to these bubbles was about four years ago, then I learned to distinguish methane from air bubbles.


'Methane bubbles freeze in layers one over the other, and the floors of them can grow 1.5 metres (5ft) deep.

'Local anglers say that other, smaller and more chaotic, bubbles are 'the breathing of Baikal seals' and point to the areas where these animals rise to the surface to take some air'.

Baikal is located in a rift zone which is a deep - in fact the largest on the planet - crack in the Earth's crust which narrows at depths of several dozen kilometres.

It does not have a solid bottom: instead there is a cushion of bottom sediments that has been filling the most narrow lower part of the crack for millions of years

These bottom sediments are similar to bogs in that they contain a lot of gas, including methane.

In deep winter, there are roads over the ice, but the larger methane bubbles pose a threat.

'There are areas of the lake where bubbles grow so big that cars fall through the ice,' he said.

Bubbles of frozen methane seen through crystal clear ice of lake Baikal.
© Stanislav Tolstnev
Bubbles of frozen methane seen through crystal clear ice of lake Baikal.
'The location may vary from year to year, and usually the large bubbles appear starting from February and can be seen through March and April.'

Scientists monitor methane rising from the floor of Baikal, and while it is said to be increasing, they have disputed this is due to global warming.

Air bubbles pictured at Lake Baikal.
© Stanislav Tolstnev
Air bubbles pictured at Lake Baikal.
Dr Nikolay Granin, from the Limnological Institute, Irkutsk, previously said: 'There are deepwater seeps - at a depth of more than 380 metres (1,247ft) - and shallow seeps, at a depth less than 380 metres.

'Currently, we have information about 22-24 deepwater seeps and more than 100 shallow seeps.'

The temperature at the bottom of the lake - the deepest in the world, with a maximum depth of 1,642 metres (5,387ft) - has not warmed, he said.

'There is a lot of speculation about this. We believe that warming does not affect the seeps, as the bottom temperature practically doesn't change.'

Yet the lake's level has fallen, and this leads to increased methane seeps, he said.

The quantity of methane hidden in gas hydrates in Baikal is estimated at one trillion cubic metres.