The twilight zone, also known as the mesopelagic zone, is the layer of the ocean that lies between about 200 to 1,000 meters (approximately 656 to 3,281 feet) below the surface. The temperature in this zone can vary significantly depending on the location and time of year, but it generally ranges from about 4°C to 10°C (39°F to 50°F).
This colder temperature is primarily due to the lack of sunlight in this region, as sunlight only penetrates the upper layers of the ocean. As you descend into the twilight zone, the water temperature decreases because it is not warmed by the sun like the surface waters are. Additionally, the density and pressure of water increase with depth, contributing to a generally colder environment.
The twilight zone is also teeming with life, including various species of fish, squid, and other marine organisms that have adapted to the cooler temperatures and darker conditions. Understanding the temperature and characteristics of this layer is crucial for marine biology and oceanography, as it plays a vital role in the overall health of the ocean ecosystem.