1. The upper, warmer layer of water in a stratified lake or ocean, above the thermocline.
Usage: technical; limnology; usually used in singular or plural form

Examples

• The epilimnia of the lake warms significantly during summer months.
• Fish in the epilimnia have access to more oxygen and sunlight than those below the thermocline.
• Temperature changes in the epilimnia affect the entire lake ecosystem.
• Researchers measured the depth and temperature of the epilimnia to study thermal stratification.
• The epilimnia gradually cools as autumn approaches and the thermocline weakens.