The ocean can be divided into two basic areas: the benthic zone or ocean floor and the pelagic zone or ocean waters. The pelagic zone is vertically divided into four zones based on how far light reaches:
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Sunlit Zone (Epipelagic): This is the uppermost layer of the ocean that sits on the continental shelf and extends from the surface down to 200 meters. It is also known as the "Sunlight Zone" because it is in this zone where enough sun rays can penetrate the waters for photosynthesis to occur. The maximum depth for this zone in clear, open ocean water is 200 meters.
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Twilight Zone (Mesopelagic): This zone extends from 200 to 1,000 meters below the ocean surface, just beyond the reach of sunlight. It is also known as the "Dysphotic Zone" because some sunlight reaches this zone, but not enough for photosynthesis to occur.
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Midnight Zone (Bathypelagic): This zone extends from 1,000 to 4,000 meters and reaches the ocean floor in many places. It is also known as the "Aphotic Zone" because no sunlight reaches this zone. The temperature here is around 4 degrees Celsius.
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Abyssal Zone (Abyssopelagic): This zone extends from 4,000 to 6,000 meters. The temperature here is around freezing, and there is no light at all.
In addition to these four zones, there is a fifth zone known as the Hadalpelagic Zone, which is the deepest part of the ocean and includes the trenches. It extends from 6,000 to approximately 11,000 meters.
Each zone has its own unique characteristics, including temperature, pressure, and the types of marine life that can be found there. For example, the Sunlit Zone is home to a wide variety of marine species because plants can grow there and water temperatures are relatively warm. In contrast, the Midnight Zone is characterized by intense water pressure and near-freezing temperatures, making it difficult for life to sustain itself. Despite this, many species have adapted and do thrive in the oceanic zone.
