Definition of thermocline in US English:



  • A steep temperature gradient in a body of water such as a lake, marked by a layer above and below which the water is at different temperatures.

    • ‘I have noticed on previous dives that most of the fish, understandably, stick to the shallows and the warmer water above the thermocline.’
    • ‘Visibility is affected by the plankton levels and thermoclines that refract the light so that an otherwise perfect image can get a woolly edge.’
    • ‘But as you descend the sides of the reef you hit a thermocline at 15-20m and it clears dramatically.’
    • ‘In summer the surface can be far warmer, at up to 15°C, but one and sometimes two thermoclines may exist, and below them the temperature plunges to near winter figures.’
    • ‘Then you hit a thermocline with warmer water below it!’
    • ‘Warm water above the thermocline is luxurious for decompression.’
    • ‘Although wind and heat loss at one location generally determine the depth of the surface layer and thermocline, the depths of these key features may be strongly influenced by rates of heating and cooling elsewhere in a basin.’
    • ‘These fish can be driven from deeper, cooler water beneath the thermocline to the warm surface water, not normally associated with sardines.’
    • ‘During the study, the thermocline gradually declined and vertical mixing started, leading to a transition from a nutrient-depleted period to a nutrient-replete period.’
    • ‘On the way down we cross a couple of thermoclines.’
    • ‘Both submarines remained below the thermocline, heading into rocky terrain.’
    • ‘Later investigations focused on the sea's thermal structure and determined that it is actually a huge body of warm water separated from the colder layers below by a pronounced thermocline - a zone of rapidly changing temperature.’
    • ‘A strong thermocline yields an oily mixing effect in the water and it is getting on for 45m before it clears enough to take photographs.’
    • ‘These waters are transported into the barrier layer, or thermocline, of the more northern oceans, where the nutrients are then absorbed by phytoplankton at the surface.’
    • ‘I was actually surprised at how comfortable I felt - until we dropped through the thermocline.’
    • ‘The school would suddenly appear through the shimmering thermocline.’
    • ‘However, the water is subject to thermoclines, so the comfortable surface temperatures extend only a few metres down.’
    • ‘Descending for the first time, I encountered a thermocline so intense that I thought something was wrong with my eyes.’
    • ‘The water was on the chilly side, my watch-thermometer recording just 3°C in the surface layers, but the temperature rose to a balmy 6°C once we had passed the thermocline in about 6m!’
    • ‘Photography is not easy in the waters around Cocos, because of the continuously varying thermoclines.’
    • ‘Beyond 40m, the pull begins to ease and I shudder as a thermocline reduces the water temperature from a cosy 26°C to a chilly 19.’