Siberia’s Lake Baikal, the world’s oldest, deepest, and largest freshwater lake, has provided scientists with insight into the ways that climate change affects water temperature, which in turn affects life in the lake. Lake Baikal is not only the world’s largest and most biologically diverse lake, but it has exceptionally strong seasonal structure in ecosystem dynamics that may be dramatically affected by fluctuations in seasonal timing.
An extraordinary, as well as asthonishing, longitudinal study of the lake’s temperature changes provided the research team led by Steve Katz the necessary data for their work. So, thanks to the dedication of three generations of a family of Russian scientists, remarkable data on climate and lake temperature were available. This 58-year record of water temperature from Lake Baikal was examined to determine how seasonality in the lake has fluctuated over the past half century and to infer underlying mechanisms.
The research team discovered many climate variability signals in the data. For example, changes in Lake Baikal water temperature correlate with monthly variability in El Niño indices, reflecting sea surface temperatures over the Pacific Ocean tens of thousands of kilometers away. At the same time, Lake Baikal’s temperatures are influenced by strong interactions with Pacific Ocean pressure fields described by the Pacific Decadal Oscillation. The researchers found that seasonality of Lake Baikal’s surface water temperatures relate to the fluctuating intensity and path of the jet stream on multiple time scales. Although the lake has warmed over the past century, the changing of seasons was not found to trend in a single direction, such as later winters. Thus, large-scale climatic phenomena affecting Siberia are apparent in Lake Baikal surface water temperature data, dynamics resulting from jet stream and storm track variability in central Asia and across the Northern Hemisphere.
The work done is relevant, because we need to go beyond detecting past climate variation. We also need to know how those climate variations are actually translated into local ecosystem fluctuations and longer-term local changes. Seeing how physical drivers of local ecology, like water temperature, are in turn reflecting global climate systems will allow us to determine what important short-term ecological changes may take place, such as changes in lake productivity. They also help us to forecast consequences of climate variability.
The climate indices reflect alterations in jet stream strength and trajectory, and these dynamics collectively appear to forecast seasonal onset in Siberia about three months in advance, according to the study.