Lake Baikal in eastern Siberia is listed as a World Heritage Site by the United Nations because of its exceptional endemic biodiversity. Its ecological and environmental health is now under threat from a government funding cut of almost 30% to the lake's long-term monitoring programme.

Biologists at Irkutsk State University have been sampling water temperature, transparency, and plankton abundance and species composition at weekly intervals, year-round, since 1945. Lake Baikal remained largely pristine in the twentieth century, but its ecosystems are changing fast as surface waters warm and winter ice cover lessens (M. V. Moore et al. Bioscience 59, 405–417; 2009 and S. E. Hampton et al. Glob. Change Biol. 14, 1947–1958; 2008).

In the lake's coastal zone, for example, excessive nutrients from industrial and household pollution are causing mass spread of the green alga Spirogyra and die-off of endemic sponges in nearshore waters (O. A. Timoshkin et al. J. Great Lakes Res. 42, 487–497; 2016).

Long-term monitoring of the health of the world's deepest lake is crucial. The cost of sustaining it (less than US$70,000 a year) is vanishingly small relative to the ecological and economic value of this global resource.