In the ocean how does water temperature change as depth increases

As we move down in the ocean, the temperature decreases. The sunlight reaches the upper surface of water and heats it.The temperature changes as the depth of the ocean increase.

The reason is sunlight does not reaches the lower part of the ocean. The density is also keeps on increasing as we move down and is maximum at 4 degree Celsius.The temperature of the water also depends on the season and climate.

every el niño cycle is different. every year.