NEET BIOLOGY

Detailed explanation-1: -Below the photic zone, from 200 to 1, 000 meters, is the aphotic (a meaning without and photic meaning light) zone. In the aphotic zone; all that’s left of sunlight is a dim, dark, blue-green light, too weak to allow photosynthesis to occur.

Detailed explanation-2: -This process is called photosynthesis. In the deep ocean, many hundreds of meters away from the sun’s rays, another process is taking place: chemosynthesis. Tiny microbes use chemical energy instead of light to combine water and carbon dioxide to make sugar.

Detailed explanation-3: -Such a minuscule amount of light penetrates beyond a depth of 200 meters that photosynthesis is no longer possible. The aphotic zone exists in depths below 1, 000 meters. Sunlight does not penetrate to these depths and the zone is bathed in darkness.

Detailed explanation-4: -Ocean water absorbs light, so light availability decreases exponentially with depth. Below about 200 meters or 650 feet, there’s not enough light for photosynthesis to take place.

Detailed explanation-5: -The majority of life on the planet is based in a food chain which revolves around sunlight, as plants make food via photosynthesis. In the deep ocean, however, there is no light and thus there are no plants; so instead of sunlight being the primary form of energy, chemical energy is produced via chemosynthesis.