Vital for making its waters so 'pure', one theory is that rising underwater methane leaks are killing off the sponge, but is there a silver lining?
One region alone - Yakutia - has 5 million tons scrap metal dumped in polar regions, an ugly Soviet legacy.
Oilmen forced to stop work after being trapped in 'horseshoe' of burning taiga, as pall of smoke smothers Irkutsk region where state of emergency imposed.
Call to locals and tourists to aid experts counter the green gunge 'polluting' world's deepest lake.
Challenge to polar doom warning from respected international expert Professor Peter Wadhams of Cambridge University.