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14.14: Divisions in the Marine Environment

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    • Contributed by Miracosta Oceanography 101
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    Divisions in the Marine Environment

    The Pelagic (open sea) environment is divided into the Neritic and Oceanic Provinces.
    Neritic (nearshore zone): Extends from shore with water less than 200 meters. It is subdivided into two zones:

    • Littoral (intertidal) zone: Interval between high and low tides
    • Sub-littoral zone: Below the littoral zone to a depth of 200 meters.
    Coral reef
    Figure 14.23. Coral reef in the neritic zone.

    Oceanic Provinces (based on depth)

    • Epipelagic: Water less than 200 meters
    • Mesopelagic: Water between 200 and 1000meters
    • Bathypelagic: Water between 1000 and 4000meters
    • Abyssopelagic: Water deeper than 4000 meters
    • Hadal: Depths below 6000 meters in deep sea trenches

    Sunlight penetration has its own divisions (Figure 14.25):

    • Photic zone: The upper part of the ocean where sunlight penetrates
    • Euphotic Zone: upper ½ of photic zone (usually to about 100 meters)
    • Dysphotic Zone: lower ½ of photic zone
    • Aphotic Zone: No light penetrates
    Depth zones
    Figure 14.24. Depth zones
    Light in oceans
    Figure 14.25. Photic Zones