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| There is really just one Ocean! It's waters mix all the way around the world. |
Oceans cover 71% of the Earth's surface with salt water. All rain and snow comes from water evaporated out of the oceans, and a molecule of H2O only spends an average of 9 days out of the oceans in the air. The salt comes from dissolved rocks that wash down streams and rivers, and accumulates because only pure water evaporates from the sea. Ocean water is interconnected everywhere on Earth in such a way that the mixture of ingredients in sea salt (the percentage of sodium, chlorine, calcium, etc) are perfectly identical everywhere.
There are other liquid salt-water oceans in our Solar System, on the moons of Jupiter and Saturn, but they are sealed underneath shells of permanent ice thousands of meters thick. Ours is the only ocean kissed by the Sun and exchanging its breath with the air. Each of us and all life on our blue ball are directly descended from the sea. Our
distant ancestors arose from seawater, and to this day every cell in our bodies carries a little seawater around to conduct its ancient business.
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| Each of our cells is made of ancestral seawater |
The current configuration (map) of continents in our little snapshot from the long movie of plate tectonics does some weird stuff to the geography of oceans. The Arctic is an Ocean surrounded by land whereas the Antarctic is land surrounded by an Ocean. The Southern Hemisphere is almost all ocean but the Northern Hemisphere is mostly land.
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| The North Pole is an ocean surrounded by land and the South Pole is land surrounded by an ocean |
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| The subtropical Gyres equalize Earth's temperatures |
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very top of the oceans is pushed around by the wind. The Trade Winds blow out of the east over the tropical oceans, and the Westerlies blow out of the west everywhere else (hence the name). There are five big swirling masses of water driven by these curling winds: the North and South Atlantic, the North and South Pacific, and the Indian Ocean. Our voyage will wend thousands of miles through three of them. In each of these great subtropical Gyres, warm tropical water flows poleward and cold polar water flows equatorward. The
ocean currents in these Gyres are a primary way that Earth balances its deficits of heat (at the poles) and cold (in the tropics).
The top 10 meters (33 feet) weigh as much as the entire atmosphere. The heat capacity of the top 2.5 meters (8 feet) of the oceans is equal to the heat capacity of the atmosphere. But the oceans are 4000 meters (13,000 feet) deep! Earth's climate is ocean climate, and climate change is ocean change. When the oceans say "jump," the atmosphere asks "how high?"
