Deep sea creatures

The other night I was watching one of the episodes of the Discovery channel's documentary "Planet Earth." In case you haven't seen any of these shows, they are truly amazing. They captured some of the most amazing video of creatures in places all over the globe - from the topics of mountains to the depths of the sea, from the lushest jungles to the most barren stretches of desert, from the poles to the equator - and everything in between. In the episode "Deep Ocean," the viewer is introduced to the largest habitat on the planet - the sea.

Deep ocean is considered anything away from the coasts and beyond the continental shelves. Out in these areas, the water can reach several miles deep. Historically, water this deep has been impossible for man to reach - the crushing pressure associated with it has been too much to overcome. But while it is too deep for man, it is not too deep for machine. In recent years, the use of remote underwater submersibles has allowed scientists to see just what is down there in the deepest parts of the world. And it turns out that this region, once considered barren and devoid of life, is not quite the wasteland we once believed. In fact, the deepest oceans in the world contain some amazing life. Amazing - and quite bizarre!

Here are a few examples of what lives in the depths of the world. (Some of these creatures are very poorly understood, given how hard it is to even find them.)
Vampire squid: The Vampire squid lives at depths of 2000 feet or more in what is called the OMZ, the oxygen minimum zone. At this depth, the amount of oxygen in the water is too low to sustain life in most oxygen-utilizing higher organisms. However, the vampire squid survives - and even thrives - in water with as little oxygen as 3%. (It is the only known cephalopod capable of this.) Interestingly, the vampire squid uses light as a defense mechanism. While shallower-dwelling squid squirt ink when startled, the vampire squid instead squirts a bioluminscent mucus that can glow for up to 10 minutes. This presumably blinds would-be predators in the inky darkness of the deep sea, allowing the squid to escape.

Sawtooth eels: These eels are so named for their inward-slanted teeth, arranged in a saw-like pattern. There are 11 known species of sawtooth eel, and they live in waters up to 2000 feet deep.

Tube worms: Tube worms are arguably some of the most well-understood deep water creature. Tube worms live around deep sea hydrothermal vents. The giant tube worm is the easiest to recognize - they can reach up to 4 feet tall, and grow more than 33 inches a year. Giant tube worms are only found in the Pacific ocean; other oceans contain tube worms such as Jericho worms, benthic worms and palm worms. These worms have a symbiotic relationship with deep see vent bacteria, which colonize the worms and provide them with energy as a byproduct of bacterial metabolism.

There are no doubt countless deep sea creatures that we know nothing of, given how difficult it is to get down there. But what little we do know about the creatures who make this region home makes me really appreciate how amazingly diverse a planet we live on.