Exploring the Deep Oceans

The deep sea seems almost to belong to another planet. Bizarre, little understood creatures live there in perpetual darkness and under mountainous pressures — vampire squids, sawtooth eels, sea spiders. They and many others have largely eluded science or appear for a tantalizing moment before the headlamps of submersibles only to vanish again. Despite decades of exploration, less than a tenth of the deep ocean realm has been explored, despite it being the largest habitat for life on Earth. There are a lot of sea monsters yet to be discovered.


The deep sea is invisible to anyone on a ship, of course. It's just the open ocean. But there are subtle signs even on the surface that great depths lie below. Creatures like great whales, albatrosses, tuna and sharks may be seen. But no sea gulls, harbor seals or otters are found in these expanses. To live in this part of the ocean, an animal has to swim all the time. There is no place to rest or hide from natural enemies.


Many species of deep ocean fish have special adaptations to living in extremely high pressure, low light conditions. Viper fish (found at 80-1600 meters - about a mile down) are some of the most wicked looking fish dredged up from the depths. Some of them are black as night all over with light organs in strategic places on their bodies, including one on a long dorsal fin that serves as a lure for the fish it preys upon. Some viperfish (and many other deep ocean fish species) don't have any pigment (color) at all - they're "see through". They also have enlarged eyes, presumably for gathering as much light as possible where there is little or no light at all. The light organs create lights by using a chemical process called bioluminescence.


Other deep ocean fish, such as the the gulper eel have a hinged skull, which can rotate upward to swallow large prey. They also have large stomachs which can stretch to accommodate a fish much larger than itself. The gulper eel is particularly well-known for its impossibly large mouth - big enough to get its mouth around (and swallow!) creatures much bigger than itself. Fish that live down here must adapt to a very low food supply, eating only "scraps" that sink down from above, or sometimes eating each other.