Ocean Zones and Marine Habitats

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Pelagic Zone Noun

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[puh-laj-ik zohn]

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Pelagic Zone

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The entire water column of the ocean, from the surface to the bottom, including all open ocean waters.

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Example: This diagram shows the Pelagic Zone as the entire open-ocean water column, separate from the coastal areas and the seafloor (Benthic realm).

Front

Benthic Zone Noun

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[ben-thik zohn]

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Benthic Zone

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The ecological region at the lowest level of a body of water, including the sediment surface and some sub-surface layers.

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Example: This diagram shows the vertical water column zones of the ocean, like the Sunlit and Midnight zones, but does not label or explain the Benthic Zone.

Front

Photic Zone Noun

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[foh-tik zohn]

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Photic Zone

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The upper layer of the ocean that receives sufficient sunlight to allow for the process of photosynthesis to occur.

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Example: This diagram shows the Photic Zone as the top layer of the ocean, down to 200 meters, where sunlight can penetrate for photosynthesis.

Front

Aphotic Zone Noun

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[ay-foh-tik zohn]

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Aphotic Zone

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The portion of the ocean where there is little to no sunlight, making it too dark for photosynthesis to happen.

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Example: This diagram shows the Aphotic Zone is the deep ocean layer below 1000 meters, where no sunlight penetrates, located beneath the Photic Zone.

Front

Euphotic Zone Noun

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[yoo-foh-tik zohn]

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Euphotic Zone

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The uppermost, sunlit layer of the ocean where the vast majority of primary production through photosynthesis takes place.

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Example: This diagram shows the Euphotic Zone, also called the Sunlit Zone, as the top layer of the ocean where sunlight can reach, allowing photosynthesis to occur.

Front

Mesopelagic Zone Noun

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[mez-oh-puh-laj-ik zohn]

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Mesopelagic Zone

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The 'twilight zone' of the ocean, from 200 to 1000 meters, where sunlight is faint and insufficient for photosynthesis.

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Example: This diagram shows the Mesopelagic Zone (Twilight Zone) is located below the sunlit surface, showing its depth and the types of animals that live there.

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Littoral Zone Noun

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[lit-er-uhl zohn]

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Littoral Zone

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The area of the shore between the high and low tide marks, also known as the Intertidal Zone.

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Example: This diagram shows the Littoral Zone (also called the Intertidal Zone), which is the area of the shore located between the high tide and low tide marks.

Front

Abyssal Zone Noun

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[uh-bis-uhl zohn]

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Abyssal Zone

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A deep layer of the pelagic zone at depths of 2,000 to 6,000 meters, characterized by complete darkness and high pressure.

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Example: This diagram shows the Abyssal Zone as a deep, flat area of the ocean floor, called the Abyssal Plain, located at depths between 4,000 and 6,000 meters.

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Thermocline Noun

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[thur-moh-klahyn]

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Thermocline

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A distinct layer in a body of water where temperature changes more rapidly with increasing depth than in adjacent layers.

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Example: This graph shows that as ocean depth increases, the temperature drops quickly in a specific layer called the thermocline, separating warm surface water from cold deep water.

Front

Marine Snow Noun

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[muh-reen snoh]

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Marine Snow

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A continuous shower of mostly organic detritus falling from upper water layers, providing food for deep-sea organisms.

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Example: This image shows a shower of small, white particles falling through the deep ocean, visually representing the concept of 'marine snow'.