06/08/2026
The internal workings of a lake are a marvel to behold and the complexities it contains are rarely apparent when gazing upon its tranquil surface.
Today, let us consider the phenomenon known as a seiche. When a steady wind drives across a stratified lake, it may gently press the warmer upper waters toward one shore, causing the boundary between warm and cold waters (the thermocline) to tilt across the basin in the direction of the prevailing wind. When the wind at last disipates, the waters seek its former balance and begins to oscillate between the shores. Like the swing of a great pendulum hidden beneath the surface, the thermocline may rise and fall from one end of the lake to the other for many hours thereafter.
Such movements are invisible to the casual observer, yet they are among the grand mechanisms by which lakes breathe, mix, and sustain life. They may even contribute to upwelling events, dispersal of algae, and the redistributing of nutrients.
At the recent ASLO–SIL 2026 Joint Conference, scientists devoted multiple sessions to these remarkable processes of physical limnology. Discussions ranged from internal seiches and upwelling to the exchange of water between interconnected lakes and basins, revealing ever more of the hidden workings of our inland waters.
The next time you gaze upon a calm lake, consider that beneath its placid surface, immense masses of water may be slowly rising, falling, and traversing the basin in rhythms as ancient as the winds themselves.
📷Photo: Mathew Wells, PhD, (University of Toronto) pointing to a slide of some of his mathematical animated models at the 2026 ALSO-SIL Conference in Montreal. https://www.youtube.com/watch?v=OgL9ZWLCNMk
