The salinity of ocean water
increases with depth
decreases with depth
is uniform throughout the entire ocean

decreases with depth

Salt has a part to play to marine life. Since water is generally shallow, photosynthetic processes are possible for marine life which attracts more organisms to their primary food sources. Since the land is near shallow waters, discharges of nutrients from the soil are brought into the sea for the consumption of organisms. Aside from these reasons, periodic upwellings in the sea also provide cool and nutrient rich waters for different species.

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