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Physical Chemistry
Thermal Stratification
The seasonal layering of warm surface water and cold deep water in lakes - creates distinct habitat zones and drives spring/fall turnover events.
Unit: layered Code: STRATIFICATION
📖 Overview
In summer, warm surface water floats over cold dense deep water. The thermocline between them is a sharp boundary. Below it, oxygen is scarce (no photosynthesis, no surface exchange). In fall, surface cooling collapses the stratification and the lake mixes - a "turnover" that releases accumulated nutrients and can cause fish kills in nutrient-heavy lakes.
❓ Why It Matters
Understanding stratification explains why anglers catch different species at different depths and why some lakes experience mass fish die-offs each fall.