The ocean is divided into three main zones based on depth and the level of light. The upper level, from 0 to 656 feet (200 meters) is called the epipelagic or in common terms, the sunlight zone. It is also known as the photic zone since this is where the most sunlight penetrates allowing for photosynthesis and the growth of plants in the ocean. The middle level is called the mesopelagic zone, or the dysphotic zone. It is often referred to as the twilight zone in common terms. It extends from 656 feet (200 meters) to 3,280 feet (1,000 meters). Some sunlight penetrates to these depths, but not enough to sustain plant growth. The bathypelagic zone extends from 3,280 feet (1,000 meters) to the depths of the ocean. It is the aphotic zone since sunlight cannot penetrate to these depths. In common terms, it is called the midnight zone.