Lake Baikal

Lake-wide physical and biological trends associated with warming in Lake Baikal

Lake Baikal, one of the world's oldest and deepest lakes, has exhibited significant physical and biological changes associated with warming over the past 26 years. Surface waters warmed by 2.0 °C lake-wide, leading to a marked increase in warm-water zooplankton species such as Cyclops kolensis (12-fold) and pelagic cladocerans (twofold), particularly in the north basin. In contrast, the cold-water endemic copepod Epischura baikalensis showed no change in abundance. While chlorophyll concentrations rose by 46% lake-wide, this increase was significant only in the south basin. Surprisingly, Secchi transparency deepened by 1.4 meters across the lake, suggesting a decline in productivity in the north and middle basins but an increase in the south. These findings indicate that Lake Baikal is experiencing warming-related changes without widespread pelagic eutrophication.