Ultraviolet radiation penetrates marine waters down to a depth of:
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Answer: C. 200 meters
Explanation
Solar ultraviolet radiation penetrates clear marine water columns down to a maximum depth of 200 meters. This 200-meter threshold marks the lower limit of the photic zone where sunlight supports photosynthesis. Beyond this specific depth, complete darkness prevents ultraviolet and visible light penetration. The photic zone is the upper layer of a body of water receiving sufficient sunlight for photosynthesis. Ultraviolet wavelengths penetrate varying depths depending on water turbidity and suspended particulate matter. Marine organisms living below the photic zone rely on alternative energy sources like marine snow.
Phytoplankton concentration is restricted to the upper 200 meters of the ocean where light is available. Climate change and increased UV radiation at shallow depths can stress sensitive marine organisms. Oceanographers measure light penetration depths to calculate primary productivity rates across marine biomes. Option A underestimates light penetration limits by stopping far too shallow at 40 meters. Option B overestimates ultraviolet penetration by extending twice as deep as actual photic limits. Option D represents a very shallow coastal depth unrelated to maximum ultraviolet penetration limits.
- Subject
- Agriculture
- Category
- Forestry
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- —
- Difficulty
- medium
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