Marine Biology

Photic Zone

유광대

Definition

The upper layer of the ocean where sufficient sunlight penetrates to support photosynthesis, typically the top 200 meters.

Detailed Explanation

The photic zone's productivity drives the entire ocean food web, yet it represents only 2% of ocean volume. Nutrients are often the limiting factor — nutrient-poor tropical gyres are the "deserts" of the sea. Light attenuation determines depth of the photic zone: clear open ocean allows light penetration to 200 m, while turbid coastal waters may limit it to 20 m. Climate change is expanding nutrient-poor zones as stratification increases.

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