Oceans
What Is Ocean Acidification, and Why It Matters
The ocean has quietly absorbed a huge share of our carbon dioxide, and that favor is changing the water itself. Ocean acidification is the slow souring of the sea, and it hits shellfish and coral first.
How Do the Tides Work, and Why Two a Day?
Twice a day the sea climbs up the beach and slides back down, on a schedule set by an object 384,000 kilometers away. Here is how the Moon, and a bit of the Sun, moves the whole ocean.
Why Is the Ocean Salty? The Science of Seawater
The rivers that feed the ocean run fresh, yet the sea is salty. Here is where all that salt comes from, how much there is, and why it keeps piling up.