DEEP SEA EXTREMES

Abyssal Zone
The abyssal zone is off the continental shelf. The shelf slopes down steeply into the deep ocean floor. It is at least 2.4 miles from the top of the ocean. After about 2.4 miles there is no light at all. The only thing deeper than the abyssal zone is the ocean trenches, they are the deepest part of the ocean!

Glass Sponge
Down on the deepest parts of the ocean, the pressure is super high. if we were to go down there, it would flatten our body! One of the animals who lives down in those extreme conditions is a glass sponge. They sound like a creature that would be very fragile, but they somehow manage to live down in the deep. How? They use silcia. It is the same thing we use to make glass. The sponge uses it to build a strong skeleton that can withstand the high ocean pressure. Scientists are studying the glass sponges to figure out how to make glass at low temperatures and how to improve optical fibers.

Moving Around
Animals so deep down still need to move around . Sea cucumbers are an invertebrate, which means they have no backbone. They are filled with water that they pump around their body so they can move and change shape. This is in the same way hydraulic pistons control a crane.

Decompression Chamber
Around Aquarius (an undersea training center for NASA) the pressure is 2.5 times higher than that of sea level. Inside the cabins, it is kept at the same pressure as the water. This is so divers can go in and out without a problem. But, in order to return to the surface, the divers must sit in a decompression chamber for 17 hours. The chamber ever so slowly reduces the pressure to match that of sea level.

Angler Fish
The angler fish might seem odd, but can it really get any weirder? The angler fish has a very strange mating system. Adult males are a fraction of the size of females. They have no stomach, so all they live to do is mate. When a male finds a mate he bites her hard. His mouth is now fused to her blood supply. After that, he lives like a parasite on the female's back. He eventually stops looking like a fish and waits until the female last eggs. A 2 foot female could have several "mates" on her.

Guess what I found really interesting about this book? Coral is an animal that is related to jelly fish They have algae living inside of them that the supply's the coral with food. Corals live in humongous colonies called reefs.

GLOSSARY

• Abyssal - describing a huge empty space
• Decompression Chamber - a tank to help people get used to different pressures
• Hydraulic - powered by pumped liquids
• Parasite - an animal that lives on another

FIVE SEA STARS