Subs explore Baikal for possible fuel of the future

For the past three summers Russian scientists have been trying to unlock the secrets of the world's deepest and oldest lake.

Yevgenii Chernyaev is the captain of one of two Russian deep-water submersibles used to explore Lake Baikal.

Mr Chernyaev told BBC News about this season's goals in Baikal's deep blue, primarily studying recently found fields of gas hydrates, a possible fuel of the future.