NeonEdgelord's Hibernal Den

The twilight zone or the mesopelagic zone begins at 200 meters and extends downward to 1,000 meters, making up approximately 20% percent of the ocean’s total depth. It is generally a very dim region, but it does receive a sliver of sunlight at the midday point which is enough for photosynthesis to occur. The mesopelagic zone is also where experts have first noted the existence of bioluminescent creatures. Temperature changes here are the most extreme.