Thermocline occurs because the warm, surface layers of water are much less dense than the cooler, deeper waters.
The depth of the thermocline depends on the depth of the lake and it’s orientation to prevailing winds. A shallow lake may not thermally stratify at all – especially if the maximum fetch (or longest uninterrupted distance across open water) is in line with prevailing winds. The thermocline is defined as the “depth at which the temperature gradient is steepest during the summer; usually this gradient must be at least 1 degree Celsius per meter of depth” according to the University of Minnesota’s Water on the Web. It’s Time to Think about the Thermocline During summer the thermocline often becomes a factor that can influence bass habitat use and movements. A thermocline is a section of lake water where the water temperature drops drastically across a small change in water depth. This occurs because warm, surface layers of water are much less dense than the cooler, deeper waters. Thermocline a transition layer between deep and surface water. The thermocline is the transition layer between the mixed layer at the surface and the deep water layer. The definitions of these layers are based on temperature. The mixed layer is near the surface where the temperature is roughly that of surface water. In the thermocline, the temperature decreases rapidly from the mixed layer temperature to the much colder deep water temperature. The mixed layer and the deep water layer are relatively uniform in temperature, while the thermocline represents the transition zone between the two Factors that affect the depth and thickness of a thermocline include seasonal weather variations, latitude and local environmental conditions, such as tides and currents. The thermocline or inversion layer occurs where the temperature profile changes from positive to negative with increasing height. The stability of the night time inversion is usually destroyed soon after sunrise as the sun's energy warms the ground, which warms the air in the inversion layer. In the ocean, the thermocline may be thought of as an invisible blanket which separates the upper mixed layer from the calm deep water below. The thermocline or inversion layer occurs where the temperature profile changes from positive to negative with increasing height. The stability of the night time inversion is usually destroyed soon after sunrise as the sun's energy warms the ground, which warms the air in the inversion layer. The thermocline varies in depth. It is semi-permanent in the tropics, variable in temperate regions (often deepest during the summer) and shallow to nonexistent in the polar regions, where the water column is cold from the surface to the bottom. A layer of sea ice will act as an insulation blanket. The thermocline or inversion layer occurs where the temperature profile changes from positive to negative with increasing height. The stability of the night time inversion is usually destroyed soon after sunrise as the sun's energy warms the ground, which warms the air in the inversion layer. Thermocline is defined by having increased temperatures in the  surface water but cold water temperatures in the deep sea due to  sunlight being unable to penetrate ocean wa … ters the deeply. thermocline is the level in the ocean/sea water that dramatically DECREASES in temperature, and the halocline is the level in the ocean/sea water that dramatically INCREASES i … n temperature. The thermocline starts at the beginning of the summer at a relatively shallow depth with little temperature difference across it. As the summer progresses, however, and more surface water is heated, the thermocline's temperature difference and depth both increase. The bottom water warms slightly due to heat transfer from the above waters, but overall the bottom water is less affected. However, the statement that the water below a thermocline is always clearer than the top water is not always true. Oxygen-poor bottom water can kill a lot of the fish and mussel life, then anaerobic bacteria start thriving and can perversely cause the bottom water to have less visibility than the top water. A thermocline (sometimes metalimnion in lakes) is a thin but distinct layer in a large body of fluid (e.g. water, such as an ocean or lake, or air, such as an atmosphere) in which temperature changes more rapidly with depth than it does in the layers above or below. The thermocline or inversion layer occurs where the temperature profile changes from positive to negative with increasing height. The stability of the night time inversion is usually destroyed soon after sunrise as the sun's energy warms the ground, which warms the air in the inversion layer.
http://msue.anr.msu.edu/news/the_thermocline_a_summer_phenomenon_in_michigan_inland_lakes http://sfrc.ufl.edu/allenlab/Popular%20Articles/Time%20to%20Think%20about%20the%20Thermocline.pdf http://ww2010.atmos.uiuc.edu/(Gh)/wwhlpr/thermocline.rxml https://en.wikipedia.org/wiki/Thermocline https://en.wikipedia.org/wiki/Thermocline https://en.wikipedia.org/wiki/Thermocline http://www.answers.com/Q/What_causes_thermocline http://www.greatlakeswrecks.info/articles_pdfs/guide_to_thermoclines.pdf https://en.wikipedia.org/wiki/Thermocline
what causes thermocline