termokliinin

Termokliinin, in Finnish usage, refers to the thermocline, a distinct layer in a body of water where the temperature changes rapidly with depth. The term is commonly used in oceanography and limnology to describe the vertically stratified zone separating warmer surface waters from cooler deeper waters.

The thermocline forms when solar heating creates a warm, buoyant surface layer that inhibits mixing with the cooler water below. This stratification causes a pronounced vertical temperature gradient over a relatively short depth interval. The depth and strength of the thermocline vary with geographic location, season, and climate; it is often more pronounced in tropical and temperate regions during the warmer months and can weaken or disappear during winter mixing in higher latitudes.

Detection and study rely on temperature profiles obtained by CTD instruments, expendable probes, and moored sensors. Remote sensing can monitor surface temperature patterns, but it cannot alone resolve subsurface gradients. Variations in the thermocline are indicators of regional climate conditions and seasonal cycles, and their dynamics are influenced by wind stirring, freshwater input, and ocean or lake circulation.

Ecological and climatic significance includes acting as a barrier to vertical mixing, which affects nutrient flux, primary production, and habitat structuring. Shifts in thermocline depth can influence fisheries, carbon cycling, and the response of aquatic systems to climate variability such as El Niño or regional droughts.

See also: pycnocline, halocline, stratification, nutrient cycling.