Don't Drink the Water!
You can not drink seawater because your body will eventually fail at trying to get rid of the salt from your system. It needs fresh water, and there is fresh water in tissue and organs, but they will eventually dry out.
The ocean is very important to us. This is because we use the ocean to trade, get food, and it contributes more then 500 billion dollars to the worlds economy. Without it, our life would be much, much worse.
The Two C's
The ocean acts like a conveyor belt. It transports precipitation and moves around hot and cold temperatures. It moves warm air closer to the poles and cold air to the equator, reheating it. Without the ocean, much less of earth would be habitable.
Zones of the Ocean
All the zones are home to different animals, light, plant life, and bacteria. There is the Sunlit Zone, with the most plants, due to sunlight. Then, there is the Twilight Zone, which has jellyfish, octopuses, and squid. Next, there is the Midnight Zone, where some of the animals lack eyes. It has Viper fish, snipe eel, angler fish, and tripod fish. Then, there is the Abyss. Animals here lack a backbone. Last, there is the Hadal Zone, which is mostly trenches and canyons.
Ocean Temperature, Depth, and Pressure
Ocean temperature and pressure change as you go deeper and deeper into the ocean. It will get more and more bone chilling as you go further down, and the pressure will build up, too. Special equipment has to be made so it doesn't compress under the pressure of the ocean.
Without the ocean, we would have a rough time. This is because it gives us food, minerals, traveling, and is drilled in for crude oil.