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The sea is salty because rain wears down rocks

Rocks on land are the major source of the salts dissolved in seawater.

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Rainwater is slightly acidic, so it erodes rock and releases ions that wash to the sea. Chloride and sodium make up around 85 percent of all dissolved ions in the ocean.

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Seawater contains gold

One study found about one gram of gold in every 100 million metric tons of ocean water.

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Coast redwoods can grow 367 feet tall

California's coast redwoods may grow to 367 feet, about the height of a 35-story skyscraper.

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About half of Earth's oxygen comes from the ocean

About half of Earth's oxygen comes from the ocean.

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