Question

Why does the twilight zone of the ocean have the greatest variation in temperature?

Answer 1

This is because twilight or mesopelagic zone (extending from 200 meters to 1,000 meters) is the zone that contains the thermocline.

A thermocline or the thermal layer is a layer in an ocean or lake where the temperature changes more rapidly with depth than in the other layers. The thermocline in twilight zone divides the upper mixed layer from the calm deep water below.